The Coming Trio of Total Eclipses


If you saw the total eclipse in 2024 (or you missed it!) you have three chances in the next three years to see another. But you will have to travel. 

Typically, total eclipses of the Sun occur about 18 to 24 months apart. Unusually, in the next three years, we have a trio of total eclipses each only a year apart. Or to be precise, a lunar year โ€” 12 lunar phase cycles โ€” apart. 

The map above (courtesy EclipseAtlas.com) plots the paths of all central solar eclipses (annulars, totals and hybrids) from 2021 to 2030. Included are the paths of the 2023 annular and 2024 total in North America you might have seen.ย 

But the next total eclipse in populated North America is not until August 2044, then again in August 2045. To see a total eclipse in the next few years, those of us in the Americas will have to travel. 

However, those in Europe can drive to the next eclipse, to their first total eclipse at home since August 1999. 


August 12, 2026

Path of the August 12, 2026 TSE, courtesy EclipseWise.com

A year from now as I write this, the Moonโ€™s umbral shadow will intercept the Earth for the first time since April 8, 2024. The path of this next total eclipse is unusual in that it starts in northern Russia, travels north over the North Pole, then sweeps down from the north to cross eastern Greenland, nipping the west coast of Iceland, then crossing Spain, to end at sunset over the Balearic Islands of Spain.ย 

Weather prospects are surprisingly good for the several cruise ships planning to be in a Greenland fjord. Iceland is iffy, but had the eclipse been this year (on August 12, 2025) many people would have seen it. Spain was the opposite โ€” statistically it has the best weather prospects along the 2026 path, but on August 12, 2025 most of the country was beset by storms. 

From northern Spain, where I intend to be and as I show above, the Sun will be low in the west in the early evening sky, for a relatively short 1m40s of totality. A low eclipse can be spectacular, but riskier as thereโ€™s a greater chance of clouds hiding a low Sun.ย 

This and the other images of the Sunโ€™s position at each eclipse are pages from my eclipse ebook, described below.


August 2, 2027

Path of the August 2, 2027 TSE, courtesy EclipseWise.com

Twelve new Moons later, the lunar shadow again crosses the Earth, this time passing over North Africa where skies are almost always clear in summer. But the days are hot! The shadow crosses the Strait of Gibraltar and passes over Morocco, Algeria, Tunisia, Libya, Egypt, and Saudi Arabia. In addition to the good weather, the attraction is that this is the longest total eclipse for the rest of the 21st century. 

The spectacular temples of Luxor, Egypt are at the point of maximum eclipse, with an unusual 6m23s of totality with the Sun high overhead. Even at Gibraltar, totality is 4m35s, seven seconds longer than the maximum in Mexico in 2024. 

From Tunisia, as I show above, the Sun is 55ยบ high over the Mediterranean, and totality is a generous 5m44s.


July 22, 2028

Path of the July 22, 2028 TSE, courtesy EclipseWise.com

Another 12 lunar months later, the Moon shadow sweeps across the southern hemisphere, for another generously long eclipse. Remote Western Australia enjoys 5m10s of totality on a winterโ€™s day. 

But millions lie in the path in New South Wales, where Sydneysiders can watch a total eclipse over Sydney Harbour lasting 3m48s. The sky scene is below, with a late afternoon winter Sun heading down in the west. From Farm Cove, the eclipsed Sun will be over the Opera House and Harbour Bridge, for a never-to-be-repeated photo op. 

The South Island of New Zealand sees a sunset eclipse (the shadow passes over Milford Sound) that lasts 2m55s, longer than the 2017 eclipse in the United States. 

Coincidentally, Australia also hosts the next total eclipse to follow, after a gap of 28 months, on November 25, 2030. And the lunar shadow crosses Australia on July 13, 2037 and December 26, 2038 โ€” a Boxing Day eclipse down under. So Australia is the place to be for the next decade or so. 

But between 2026 and 2028, Spain is host to three eclipses, as the 2027 total crosses Spanish territory, and the January 26, 2028 annular eclipse ends at sunset in western Spain. At this eclipse the Moon is not large enough to completely hide the Sun, so at mid-eclipse we see a bright ring of light, similar to the annular eclipse here in North America on October 14, 2023. 


My Plans

Where will I be? For 2026 I have signed onto a trip to Spain with the well-travelled photo tour company CaptureTheAtlas.com.

They are planning a very photo-centric tour to Spain for viewing the eclipse from a winery near Burgos. Iโ€™ll be one of the instructors, among a stellar line-up of eclipse veterans and astrophoto experts. I invite you to check out the details of the tour here at its webpage. Weโ€™d love to have you join us!ย 

For 2027 I am planning to be in Tunisia, on the Mediterranean coast, with a tour group from Astro-Trails.com.ย 

For 2028 I can return to Australia on my own, to view the eclipse from the very areas I go to anyway on my trips down under for night sky photography.ย 

The path of totality passes just a few kilometres from Coonabarabran, the โ€œAstronomy Capital of Australia,โ€ as the Siding Spring Observatory is just down the Timor Road in the path. In July the Milky Way is at its best, with the centre of the Galaxy high overhead at nightfall. Thatโ€™s a sight equal to an eclipse for bucket-list spectacle.


My EBook 

The cover of my new 400-page ebook

For 2017โ€™s eclipse I prepared an ebook on how to photograph it. It proved popular, and so for the 2023 and 2024 eclipses I revised it to cover both the annular and total eclipses. 

Its popularity prompted me to revise it again, this time to cover the coming trio of eclipses, plus I included pages on the January 2028 annular, as many who visit Spain for the totals may plan to return for the sunset annular (low annulars are also the most spectacular!). 

My new ebook is 40 pages larger than the previous edition, with most of the added content in the 100-page chapter on processing eclipse images, from wide-angles, to time-lapses, and to blended exposures of totality close-ups.ย I include lots of information on choosing the right gear โ€” filters, camera, lenses, telescopes, and tracking mounts.

The slide show above presents images of sample pages.ย Do page through the gallery for a look at the content.

But for all the details and links to buy the book (from Apple Books or as a PDF for all platforms) see its webpage at my website. ย 

It will be a busy three years for eclipse chasers, as rarely do we get three-in-a-row like this. The diversity of locations and eclipse circumstances make this an exciting trio to chase. But you can just go back to Spain to see most of them! 

โ€” Alan, August 14, 2025 / AmazingSky.com ย 

Touring the Constellations of Spring


Join me in a guided tour of the famous (and not so well known!) constellations of the northern spring sky.

The northern spring sky lacks the splendour of bright patterns such as winter’s Orion or summer’s Cygnus, but it is still well worth getting to know. The Milky Way is out of sight, and in its absence we are left with fewer bright stars to dazzle us at night. But we are treated to the year’s best views of famous constellations such as Ursa Major, Leo and Virgo.

Now, I am talking about the sky of the northern hemisphere, where April and May brings spring, and places the Big Dipper high overhead. While some of these constellations can be seen from the southern hemisphere, they appear to the north, low and “upside-down” from the views I present here. And April and May are autumn months.

Let’s start with the “big picture.” (Tap on images to bring them up full screen.)

NOTE: I shot all these images during a run of fine nights in mid-April 2025 with a 15-35mm zoom lens on a Canon EOS R camera, and on a Star Adventurer tracker. Separate exposures through a Tiffen Double Fog 3 filter added the star glows.

This image, in labeled and unmarked versions, presents a wide view of the spring sky from horizon to well past the zenith overhead. The key pattern to look for is the Big Dipper, at its highest in northern spring. In the UK and Europe it is known as the Plough or Wagon. Look way up to find it first.

Its Pointer Stars in the Bowl famously point north to Polaris. But here I show the other pointer line off the Bowl, to the south, to Leo the Lion. It is well known as one of the constellations of the Zodiac. Leo is marked by one of the brightest spring stars, Regulus.

Use the Handle of the Dipper to arc downward, to locate the brightest star of spring, Arcturus, shining with a yellow light. Keep that line going south and you’ll come to a dimmer and bluer star shining in the south. That’s Spica, the brightest star in Virgo, the Zodiac constellation east of Leo.

Now let’s take a closer look at selected areas.

Ursa Major, Leo and Boรถtes

This is still a wide view, looking up and high in the south. There’s the Big Dipper/Plough at top. It is not a constellation. It is an “asterism” of seven stars within the large constellation of Ursa Major, the Great Bear. With a little imagination you can join the dots to make a bear (many northern cultures did so). Except we draw him with a long tail, which bears do not have!

The paws of the Bear are marked by a trio of double stars: Alula Borealis and Australis, Tania Borealis and Australis, and Talitha and Talitha Australis. The names come from Arabic words for “first,” “second,” and “third” as these sets of double stars are collectively called the Three Leaps of the Gazelle in Arabic sky lore. Once you see them you’ll be surprised at how distinctive they are.

Below Ursa Major is Leo, a pattern that does look a little like a sitting cat. Its bright star Regulus was named by Copernicus, from a Latin word for “little king.” But Regulus has long been known as the heart of the Lion.

To the east lies brighter Arcturus, a name that means “bear watcher,” as it and its host constellation Boรถtes, the Bear Herdsman, are tied to Ursa Major and Minor in Greek mythology.

Leo, Cancer and flanking clusters

Here I frame Leo, but also two of the constellations that flank him: Cancer the Crab to the right (or west) and Coma Berenices to the left (or east). Each contains a bright naked eye cluster of stars:

  • Messier 44 or the Beehive cluster in Cancer, the faint Zodiac pattern west of Leo. When I shot this image in mid-April 2025 red Mars was just entering Cancer.
  • and Melotte 111 in Coma Berenices. At one time this clump of stars easily visible to the naked eye was considered part of Leo, as the tuft on the end of his tail. The area was broken off as its own constellation in the 3rd century BCE, and named for Queen Berenice of Egypt, and for her legendary hair (“coma”).
  • Together, the obvious pattern of Leo and the star clusters that flank him form one of the spring sky’s most notable sights.
Leo and Leo Minor

The head of Leo is marked by a curving arc of stars popularly called The Sickle. Or it is thought of as backwards Question Mark, with Regulus the dot at the bottom. Leo is one of the oldest constellations, as there are records of this pattern dating back to 4000 BCE in Mesopotamia.

More modern is the obscure pattern above it, Leo Minor, the Little Lion. It was invented by 17th century star chart maker Johannes Hevelius, to fill in a blank area of sky. Even in a dark sky, it is tough to make out its innocuous pattern between Leo and Ursa Major.

Canes Venatici, Coma Berenices and Boรถtes

Another obscure pattern created by Hevelius lies below the Handle of the Big Dipper. A sparse pattern of stars marks Canes Venatici, the Hunting Dogs that belong to Boรถtes to help him herd bears! While not much to look at with the naked eye, Canes Venatici does have superb targets for telescopes, such as the double star Cor Caroli and very red star La Superba.

Below the Dogs lies Berenices’ Hair, home to the star cluster Mel 111, but also the North Galactic Pole (NGP). This is the point 90ยบ away from the plane of the Milky Way and the Galactic Equator seen in our winter and summer skies. But in spring we look straight up out of our Galaxy, to many other telescopic galaxies that inhabit Coma and Virgo, our next stop.

Virgo, Corvus, Crater and Hydra

Below Leo and Boรถtes lies the Zodiac pattern of Virgo, usually thought of as the reclining Greek goddess of agriculture and the harvest. Spica is easy to see, but the sprawling pattern of the rest of Virgo is not so obvious. It takes a dark sky to pick out the other fainter stars of the goddess.

Easier to see, despite its low altitude from northern latitudes (it skims my horizon), is the quadrilateral pattern of Corvus the Crow, a constellation that dates from the 2nd century CE and the star catalogue of Ptolemy. The Crow sits on the tail of Hydra the Water Snake, a long zig-zag line of stars that is only partly contained here. The head of Hydra, off frame to the right here, is in the earlier image of Leo and Cancer.

Another pattern riding the back of Hydra is Crater the Cup, associated with Corvus and Hydra in a Greek myth in which the Crow is sent to fetch water for Apollo but fails. Apollo flings the Crow, Cup and Snake into the sky. Angering the gods could get you immortalized in the sky!

Boรถtes, Corona Borealis and Hercules

Heading back north above Virgo, we return to the kite-shaped pattern of Boรถtes above Arcturus, the brightest star in the northern half of the sky. Coming up later on spring evenings, and to the left is a semi-circle of faint stars, the Northern Crown, or Corona Borealis, another of Ptolemy’s patterns from the 2nd century. The crown belongs to the princess Ariadne.

Astronomers have been watching Corona Borealis closely in recent months, waiting for a recurrent nova star to explode and add a new jewel to the Crown. So far, no luck. T CorBor remains stubbornly dim.

To the east of Corona is the H-shaped pattern of Hercules, the Roman name for the Greek hero Heracles. Among his many labours and conquests, he slewed Cancer the Crab and Leo the Lion.

Libra and Scorpius

Returning down south and scraping the horizon from my northern latitude late on spring nights are the next two constellations of the Zodiac east of Virgo: Libra the Scales and Scorpius the Scorpion.

Libra is a faint pattern but with the wonderfully named stars Zubeneschamali and Zubenelgenubi, meaning the northern and southern claws, as these stars were once considered part of the Scorpion. However, Libra has long been seen as a balance or scales for meting out justice. It is the only Zodiac constellation that is an inanimate object.

Scorpius is one of the few patterns that looks like what it is supposed to be, though here I see only the northern part of the constellation. His curving tail has yet to rise as the Milky Way comes into view low in the south just before dawn this night. The bright orange star is Antares, the heart of the Scorpion, set in an area rich in dark and colourful nebulas.

The appearance of Scorpius signals the return of the Milky Way to the sky, and the rise of the summer constellations.

But no astronomical life is complete without getting to know the patterns of spring. Clear skies and happy stargazing!

โ€” Alan, April 30, 2025 (amazingsky.com)

Chasing the Red Moon to the Mountains


It took a last-minute chase, but I managed to capture the total eclipse of the Moon on March 14, 2025.

It would not be an eclipse without a chase. Solar eclipses of the total kind almost always involve travel, often to exotic locales around the world. But total lunar eclipses come to you, as they can be seen from an entire hemisphere of the planet.

Except there’s one problem โ€” clouds! Over the last decade since 2014, of the eight total lunar eclipses (TLEs) I was home in Alberta for, I had to chase into clear skies for all but one. A recounting of one such chase from January 2019 is here.

Only for the TLE before this most recent (on November 8, 2022) was I able to stay home to watch it. Though in that case a snowstorm the day before made the roads and travel poor, so I had to stay home. I recounted that eclipse story here. You’ll find links to my other lunar eclipse stories below.

Once again, for the March 13/14, 2025 TLE, weather prospects looked poor. Not just in my area but in many regions of the continent. But there was hope!

Astrospheric and Environment Canada cloud forecast + Moon information

The forecast cloud cover showed home to be hopeless. But a clear area was supposed to be open in southwestern Alberta, marked by the red circle above. That’s Waterton Lakes National Park, just on the US border. It’s a favourite place of mine for nightscape photography anyway (see my blog from this past summer here).

The chart above from the app Astrospheric shows the clear hole, and the dark blue on the time-line indicates the period with no clouds. Note how it coincides with the wavy line below which shows Moon altitude, with the orange and red regions indicating when the eclipse would take place. Looks good! So I made my plan to chase.

I knew the area well enough to know the site would be a good one for the eclipse, and the Moon’s location to the south. But it pays to check. I use The Photographer’s Ephemeris as my main photo planning app.

TPE Plot of Sightlines

It showed the sightline toward the Moon during the eclipse as straight down Upper Waterton Lake. My chosen spot was on the lakeside Waterton Avenue, where I could set up both the wide-angle camera and a telescope without having to heft gear any distance. Winter road closures also limited my site choices. Indeed, in winter the Park is quiet, with only a few hotels and restaurants open, and many businesses boarded up.

TPE 3D Simulation

Switching to the companion app TPE 3D (above) showed a preview of the landscape and the Moon’s position in the sky relative to the scene below.

Compare the simulation to the real thing below! Pretty accurate, except for the scattered clouds that drifted through.

This is a blend of separate images for the sky and ground: a stack of two untracked images for 60 seconds each for the ground, then a third exposure for the sky and untrailed stars, taken immediately afterwards with the tracker motor on, for 30 seconds, all with the Canon RF15-35mm lens wide-open at f/2.8 and at 20mm, on the Canon R5 at ISO 1600. Separate shorter tracked exposures of 15, 8 and 4 seconds blended in kept the lunar disk from overexposing, showing it more as the eye saw it.

The above image is a blend of tracked exposures for the Moon and sky, with untracked exposures for the ground. I shot them just before mid-totality at 1 am MDT. That image was second in priority. First, was a panorama. That result is below.

This is a panorama of four segments at 30ยบ spacing, taken in two passes: first untracked for 30 seconds each, then a second pass immediately afterwards with the tracker motor on, also for 30 seconds each, all with the Canon RF15-35mm lens wide-open at f/2.8 and at 20mm, on the Canon R5 at ISO 1600, with the camera in landscape orientation. Separate shorter exposures of 15s, 10s, 5s and 2.5s at ISO 400 were blended in to preserve the lunar disk more as the eye saw it.

I shot this scene just as totality began, to ensure I got it. While the Moon was in clear sky before totality during the partial phase, sure enough as the Moon became fully eclipsed, the clouds wafting over the mountains threatened to move in and obscure the view.

Luckily, while they did hide the Moon now and then, they opened up enough for good views and images for a few minutes at a time throughout the eclipse.

For the panorama I processed the image for a more monochromatic look, to resemble the naked-eye view, but with the Moon appearing as a red globe in the sky, the only colour in the scene. (I shot the tracked shots with the MSM Nomad tracker I reviewed here.)

The site proved excellent, but it was a cold night! While the temperature was only just below freezing, the brisk Waterton wind off the lake made it a chilly experience watching the eclipse for two hours. I was actually being hit by ice pellets blowing off the lake.

I decided not to set up the telescope for close-ups; the wide-angle images were the priority anyway from such a scenic spot.

A single untracked 15-second exposure with the RF15-35mm lens at f/2.8 and 17mm on the Canon R5 at ISO 3200.

But I am not complaining. I got the eclipse, once again by chasing to where the weather predictions said it would be clear. The above is my requisite trophy shot.

Had I stayed home I would have been clouded out. Had predictions called for clear skies at home, I would not have made the trip to Waterton to enjoy the eclipse over its wonderful scenery.

The next total lunar eclipse is September 7, 2025, six months after this eclipse. But it is visible from the opposite hemisphere to this one, with no part of that eclipse visible from North America. I will not chase that far for a TLE!

The March 3, 2026 TLE from Alberta

After that, and after a passage of one lunar year (355 days or 12 lunar cycles) since the March 14, 2025 TLE, I have a chance for another total lunar eclipse from home, with western North America favoured. As I preview above, it’ll be an early morning event on March 3, 2026, with the eclipsed Moon setting in the west in the pre-dawn hours.

Sounds like another chase to a mountain site with the red Moon over the Rockies. That’ll be the plan!

โ€” Alan, March 15, 2025 / AmazingSky.com

Deep-Sky Hunting in the Other Galaxy Season


Each season brings a different and rich set of targets to view through telescopes. Summer and winter skies are dominated by the Milky Way and its assortment of glowing nebulas and sparkling star clusters, objects not far away within our Galaxy’s spiral arms. 

We live in a galaxy that is a flattened disk โ€” though, as shown in this artwork based on data from the European Space Agency’s recently concluded Gaia mission, that disk is warped. 

Image courtesy ESA

In summer and winter, as viewed from our location halfway from the centre to the edge of our Galaxy, we look into its disk, to see our Galaxy as the “Milky Way,” the misty band across the night sky. 

But in spring we look straight out of the disk, into intergalactic space filled with other distant galaxies. In northern hemisphere spring we look “up” in this illustration, out of the disk toward the North Galactic Pole, and the rich collections of galaxies in Coma Berenices, Leo, and Virgo.

In southern hemisphere spring โ€” and from the southern hemisphere โ€” we look “down” in the diagram, toward the assortment of galaxies around the South Galactic Pole, in and around the lesser-known constellations of Eridanus, Fornax and Sculptor. 

A SkySafari chart showing some of the targets on the tour, low in the south from Arizona’s latitude in autumn.

But, as I show above, that area of sky is accessible from sites in the northern hemisphere, when it is autumn. (The marker for SGP is the South Galactic Pole.) As you can see, the galaxy-filled constellations lie low in the southern sky. It takes travelling to a site as far south as possible to see them well.

That’s what I did in October 2024, to a favourite spot just north of the Mexican border near Portal, Arizona (latitude 32ยบ N). I blogged about that trip earlier.

Here I provide a tour of some of the deep-sky delights I shot on that trip, during autumn “galaxy season,” the other galaxy hunting time. All these galaxies are bright, rivalling the better-known northern targets in the popular 18th-century Messier Catalogue. But French astronomer Charles Messier never observed from this far south to see them. And yet, some of these targets are large and bright enough to be visible in binoculars, ranking them as “showpiece” objects. 

NOTE: You can tap or click on all images to bring them up full screen.

NGC 55 in Sculptor

This is a stack of 16 x 4 minute exposures with the Askar APO120 refractor at f/5.6 (with its 0.8x Reducer) and the Canon Ra at ISO 1000.

This bright (8th magnitude) edge-on galaxy is big, almost 1/2ยบ across (as wide as a Full Moon diameter โ€” the field here is 2ยบ by 3ยบ). NGC 55 lies on the border of the obscure southern constellations Sculptor and Phoenix.

The galaxy was discovered by James Dunlop from Australia in 1826. It is one of the brightest members of the Sculptor Group of galaxies near the South Galactic Pole, though some consider it a member of our own Local Group of neighbour galaxies. It has an asymmetrical shape and is crossed by dark dust lanes. It is classed as a barred spiral, though that shape is hard to discern; we’ll see better examples later in the tour. 

NGC 247, the Dusty Spiral in Cetus

This is a stack of 16 x 4 minute exposures with the Askar APO120 refractor at f/5.6 with its 0.8x Reducer, and the Canon Ra at ISO 800.

This is the bright (9th magnitude) and moderately large spiral galaxy NGC 247 in southern Cetus, the Whale. It is known as the Dusty Spiral and is #62 in Sir Patrick Moore’s Caldwell Catalogue of notable non-Messier objects.

It is also a member of the Sculptor Group of nearby galaxies close to our own Local Group that surrounds the Milky Way. A group of tiny and faint 14th to 16th magnitude “PGC” galaxies (from the Principal Galaxies Catalogue) called Burbidge’s Chain lies just above NGC 247. 

NGC 253, the Silver Coin, with NGC 288, a Pairing in Sculptor

This is a stack of 20 x 3-minute exposures with the APO120 refractor with its 0.8x Reducer for 560mm focal length and f/5.6, and the Canon Ra at ISO 1600. No filter was employed.

Here, sitting right next to the South Galactic Pole, we get a two-for-one field. This is the pairing of the bright and large edge-on spiral galaxy NGC 253 (upper right) with the large and loose globular star cluster NGC 288 (lower left). The latter is easily resolved into its constituent stars.

The two are just 1.75 degrees apart in Sculptor, but are actually 12 million light years apart in space, with NGC 288 belonging to our Milky Way, while NGC 253 is another galaxy altogether, one of the brightest in the sky (at magnitude 7) and a member of the Sculptor Group. 

NGC 253 is also known as the Silver Coin Galaxy, and is Caldwell 65 on Sir Patrick Moore’s list. However, it was discovered by Caroline Herschel in 1783, from England! Her brother William discovered nearby NGC 288.

NGC 300, the Sculptor Pinwheel

This is a stack of 16 x 4 minute exposures with the APO120 refractor at f/5.6 with its 0.8x Reducer, and the Canon Ra at ISO 800.

This is the bright (8th magnitude) and moderately large (1/2ยบ across) spiral galaxy NGC 300, aka the Sculptor Pinwheel. It’s the southern equivalent of the popular Messier 33 spiral in Triangulum. NGC 300 is also Caldwell 70.

It, too, was discovered in 1826 by James Dunlop. NGC 300 may be a member of the Sculptor Group. Or it might lie closer to us than the Sculptor Group, along with NGC 55, at “only” 6.5 million light years away. 

NGC 1097, a Barred Spiral in Fornax

This is a stack of 10 x 6 minute exposures with the APO120 refractor at f/7, with the Canon Ra at ISO 1600.

We trek farther east into the next constellation over from Sculptor, to Fornax the Furnace, to find NGC 1097. This is the realm of bright (magnitude 9.5 in this case) barred spiral galaxies. This class of galaxy has arms emanating from a long bar at the core. This area of sky is replete with bright barred spirals, far more so than any area we find “up north.”

NGC 1097 is also classified as a Seyfert galaxy, a type with an active quasar-like nucleus, housing a massive black hole. NGC 1097 is also Caldwell 67. Just on its northern edge sits the little companion galaxy NGC 1097A. 

NGC 1316 in Fornax, also with a Black Hole

This is a stack of 15 x 4 minute exposures with the APO120 refractor at f/5.6 with its 0.8x Reducer, with the Canon Ra at ISO 800.

This bright (magnitude 8.5) elliptical galaxy is also catalogued by radio astronomers as Fornax A, because NGC 1316 is also a “bright” source of radio waves, thought to be generated by a supermassive black hole at its core.

Elliptical galaxies are notorious for being cannibal galaxies, eating others nearby. Sure enough, the galaxy is surrounded by faint tidal streams of stars, just recorded here, the result of collisions and mergers with unfortunate companions that wandered too close by. NGC 1316 is about 75 million light years away, and belongs to the Fornax 1 Galaxy Cluster. Despite its uniqueness and brightness, it is not in the Caldwell Catalogue. 

Just above it is the smaller elliptical NGC 1318. At top is the trio of: the edge-on spiral NGC 1326A and companion NGC 1326B, and the barred spiral NGC 1326 with an odd ring shape. 

NGC 1365 and NGC 1399, at the Heart of the Fornax Cluster

This is a stack of just 10 x 6 minute exposures through the APO120 refractor at f/7 and the Canon Ra at ISO 1600.

This frames the main members of the populous Fornax Galaxy Cluster, second only perhaps to the northern sky’s Coma-Virgo Galaxy Cluster, and its Markarian’s Chain area, for having the most bright galaxies in one low-power telescope field. (The field here is 1.6ยบ by 2.4ยบ.) It is a “must see” sight for galaxy fans.

The two brightest Fornax cluster members are:
– the giant elliptical galaxy NGC 1399 at upper left, paired with smaller NGC 1404,ย 
– and the barred spiral galaxy NGC 1365 at lower right, considered one of the best barred spirals in the sky.ย There’s nothing quite like it up north. Like NGC 1399, it is 58 million light years away.

The odd shaped galaxy at left is the irregular galaxy NGC 1427A, with NGC 1427 itself at the far left edge. The elongated spiral galaxy at top is NGC 1380. Numerous other NGC and tiny, faint PGC galaxies populate the field, down to magnitude 15 or so.ย 

While autumn’s galaxy season has lots to offer the galaxy hunter, there are some wonderful nebulas down south as well. In my sampling, all are “planetaries.” 

NGC 246, the Skull Nebula in Cetus

This is a stack of 16 x 4 minute exposures with the Askar APO120 refractor at f/5.6 with its 0.8x Reducer, with the Canon Ra at ISO 1600.

This is the nebula NGC 246, aka the Skull Nebula, in Cetus. It’s an example of a planetary nebula, so-called because this type of object with their small blue-green disks reminded William Herschel of the planet Uranus that he discovered in 1781. NGC 246 was discovered by Herschel four years later in 1785.

NGC 246 has a mottled disk, giving it its fanciful name, and a 12th magnitude central star that has ejected the nebula as part of its end-of-life eruptions, the origin of all planetaries. They have nothing to do with planet formation; they are the products of star death.

NGC 246 lies about 1,600 light years away. Just above it is the small galaxy NGC 255. 

NGC 1360, the Robin’s Egg Nebula in Fornax

This is a stack of 10 x 6 minute exposures with the Askar APO120 refractor at f/7 and with the Canon Ra at ISO 1600.

This, too, is a planetary nebula, but an odd one, in that it is a more uniform disk than is usual for planetaries, lacking the ring or bi-polar shape of most such objects. It was only recently classified as a planetary, one with an 11th magnitude central star responsible for expelling the nebula.

NGC 1360 is bright (at 9th magnitude), large, and blue-green, giving it the nickname the Robin’s Egg Nebula. The barred spiral galaxy (there are lot of them down here!) NGC 1398 is at lower left. 

NGC 7293, the Helix Nebula in Aquarius

This is a blend of: a stack of 24 x 8 minute exposures with no filter, with a stack of 20 x 12 minute exposures with an IDAS NBX narrowband filter to isolate just the green Oxygen III and red Hydrogen alpha light. All through the APO120 at f/7, taken over 2 nights as the object was not well-placed long enough for all the images to be taken in one night. Shot using the Canon Ra, at ISO 3200 for the filtered frames and ISO 1600 for the unfiltered shots.

This is the large and bright (magnitude 7.6) planetary nebula catalogued as NGC 7293, but better known as the Helix Nebula, in Aquarius. But the internet has also dubbed in “The Eye of God.”

While this target lies farther north than most of the objects here, making it easy to see from northern latitudes, William Herschel working in England missed it. His telescopes were too powerful! It wasn’t discovered until 1824 (or thereabouts) by Karl Ludwig Harding in Germany. It is #63 in the Caldwell Catalogue. 

NGC 7293 is thought to be one of the closest planetary nebulas to us, at only 650 light years away, thus its large size, nearly 1/4ยบ across, half the size of the Moon’s disk. There’s an outer halo that is twice that size, but only the brightest portion of it is recorded here as a partial arc. It takes exposures of many hours, and more patience than I have, to pick up this nebula’s full extent.

The bright star at left is 5th magnitude star Upsilon Aquarii, which I composed to be in the frame and not on the edge if the Helix had been centered. 

As per the tech details in the captions, I shot all the images from southern Arizona during a wonderful marathon of astrophotography in October 2024, at the Quailway Cottage, a favorite spot of mine for an astronomy retreat.

I used an Askar APO120 refractor, at either its native f/7 for a focal length of 840mm, or with its 0.8x Reducer lens for a faster f/5.6 focal ratio and shorter 670mm focal length, yielding a wider field and shorter exposure times for each “sub-frame.” Most images have a similar “plate scale,” so the difference in object size is due to their actual size on the sky.

The camera was the astro-modified 30-megapixel Canon Ra. The mount was the venerable Astro-Physics AP400, which returned earlier in 2024 from its 20-year stay in Australia. I used the Lacerta MGEN3 stand-alone auto-guider, for app- and computer-free guiding which I prefer. The MGEN3 performs “dithering,” shifting the framing by a few pixels between each exposure, to aid elimination of thermal noise when stacking images.

While it looks impressive, the telescope is still not the best for small, detailed targets like the galaxies and planetaries here. They demand even more focal length (= bigger and heavier telescopes) than I prefer to shoot with.

Even so, I plan to take the same rig to New Mexico this year in May to shoot targets in the “other half of the sky,” during spring galaxy season.

โ€” Alan, January 24, 2025 / AmazingSky.com

The Great Comet Chase of 2024


A plan to shoot the promised bright comet of 2024 paid off, with fine views at dawn and at dusk of the best comet since 2020. 

Comets are always a gamble. Any new comets discovered, the ones that usually become the brightest, have no track record of performance. Predictions of how bright a new comet might appear are based on what a typical comet should do. But comets can outperform expectations and dazzle us, or they can fizzle and fade away. 

In late 2023 it was clear that a then newly-discovered comet, C/2023 A3, named Tsuchinshan-ATLAS after the observatories where it was co-discovered, had the potential to perform in late 2024.ย 

The low angle and position of the comet from home in Canada in the late September dawn sky, simulated in StarryNight software.

Knowing where it would be in the sky (that trait of a comet can be predicted with accuracy!) I planned a field trip to the U.S. desert Southwest for late September and early October 2024. From farther south the comet would be higher than it would be from home (shown above), and over spectacular landscapes. 

I had visions of another Comet NEOWISE from July 2020. As my blog from 2020 shows, we saw that photogenic comet well from our northern latitude in Canada, as it skimmed across the northern horizon. Tsuchinshan-ATLAS would require a chase south.ย 


September 26 & 27 โ€” at Bryce Canyon, Utah

In late September 2024 the comet would be inbound, approaching the Sun and in the morning sky. What better eastern scene than overlooking Bryce Canyon in Utah, where I had been a year before, for the October 14, 2023 annular eclipse of the Sun in the morning sky. (Click the link for my eclipse chase blog.)

I was fortunate to get two clear mornings, both from the Fairyland Canyon viewpoint, just a short walk from the parking lot to carry camera gear and tracking mounts. 

Comet C/2023 A3, Tsuchinshan-ATLAS, at dawn over Bryce Canyon, on the morning of September 27, 2024.

My first look at the comet on September 27 was on the day the comet was at perihelion, closest to the Sun in its orbit, though not in the sky at our viewing angle from Earth. 

The comet was just visible to the unaided eye, but was obvious on the camera view screen, even amid the bright twilight. I had to shoot fast as the window between โ€œcomet riseโ€ and the sky brightening too much was only a few minutes long. 

Comet C/2023 A3, Tsuchinshan-ATLAS, rising in the twilight over Bryce Canyon, on September 28, 2024.

Knowing better what to look for, I caught the comet a little sooner the next morning on September 28, and so the tail appeared longer and more impressive as it rose above the distant mountains. A group of other local photographers arrived just a few minutes too late both mornings, and so struggled to just sight the comet, let alone photograph it. 

This vertical panorama takes in the nebula-rich northern winter Milky Way over the formations of Bryce Canyon National Park, from the Fairyland Canyon viewpoint.

But I had arrived extra early, to shoot a vertical panorama (above) of the winter Milky Way over the canyon formations below. This and the comet images were shot with the aid of a sky tracker to follow the stars, but with the tracker off for separate shots of the ground. 

So I had bagged the comet at Bryce! On to the next stop.


September 28 & 29 โ€” at Monument Valley, Utah

Thereโ€™s no more iconic or famous landscape in the American West than the buttes of Monument Valley, on the Navaho Tribal Lands on the Arizona/Utah border. 

This panorama from the Navaho Tribal Park at Monument Valley shows the evening twilight sky looking east opposite the sunset to the rising dark blue arc of Earth’s shadow cast on the atmosphere. The shadow is rimmed with a pink “Belt of Venus” tint from sunlight still hitting the upper atmosphere.

A clear first evening provided a fabulous view of the arc of Earthโ€™s shadow across the eastern sky from the viewpoint near the aptly named The View Hotel. 

This is a panorama of the sunrise scene at the Navaho Tribal Park, Monument Valley, Arizona, taken just after sunrise with the low Sun lighting the iconic buttes and mesas of the Valley. The West and East Mittens are at left; the Sun was behind Merrick Butte at centre, and lighting Mitchell Mesa at right.

A wonderful sunrise on my second morning there made for a spectacular panorama. But while clouds created fine sunrise lighting, they arenโ€™t conducive to seeing comets!

Comet C/2023 A3, Tsuchinshan-ATLAS (at centre), is rising in the dawn twilight over Monument Valley, Arizona on the morning of September 30, 2024. The comet is rising just south (right) of Merrick Butte.

A band of clear sky near the horizon allowed me to catch the comet rising to the right of Merrick Butte, as seen from a spot south of The View from where I had calculated the comet would rise in the right position. From the usual Valley viewpoint farther north the comet would have been behind the butte. 

While the planning worked, the result was not quite the spectacle I had envisioned. The comet was nice, but was starting to become lost in the bright sky as it descended toward the Sun. 

There were only a couple of mornings left to catch the comet at dawn before it disappeared completely into the daytime sky close to the Sun. 


October 1 to 11 โ€” at Quailway Cottage, Arizona

The major block of time in my trip was booked for an astrophoto retreat at a cottage Iโ€™d rented twice before but not since late 2017. The Quailway Cottage, popular among birders, is also ideal for stargazing as it is in one of the darkest areas of the Southwest, north of Douglas, Arizona, and just across the Arizona/New Mexico border. 

This captures both the glow of Zodiacal Light in the eastern dawn sky (the band of light extending up across the frame) and the dust tail of Comet Tsuchinshan-ATLAS rising from behind the Pelloncillo mountains, at dawn on October 2, 2024.

When I arrived the comet was putting in its last show in the dawn sky. In fact, on October 2 I managed to capture a dawn scene with the morning Zodiacal Light created by sunlight reflecting off cometary dust in the inner solar system, and just the tail of the comet rising before the bright comet head appeared.

Comet C/2023 A3, Tsuchinshan-ATLAS, is rising in the dawn twilight over the Pelloncillo Mountains in New Mexico, on October 2, 2024.

An image taken a little later showed the entire comet, now sporting a more impressive tail. It was blossoming into a fine comet indeed. But we were about to lose sight of it for more than a week. 

Arizona Deep-Sky Imaging 

While at Quailway I had clear skies every night. And so, as planned, I went to town shooting all kinds of โ€œdeep-skyโ€ objects and fields with two astrophoto rigs I had brought with me: a longer-focal length 120mm refractor for small targets, and a short-focal length refractor for wide fields in the Milky Way. I had reviewed both new telescopes in recent months. 

I concentrated on shooting targets low in the south that are impossible to get from home in Canada, and that Iโ€™ve missed shooting, or have not shot well, during my visits to Australia.ย See my blog here about my latest trek Down Under.

The two brightest Fornax cluster members are the elliptical galaxy NGC 1399 at upper left, paired with smaller NGC 1404, and the galaxy NGC 1365 at lower right, considered one of the best barred spirals in the sky.

Hereโ€™s an example, above, with the larger Askar 120APO: a field of galaxies in the constellation of Fornax that rivals the better-known Markarianโ€™s Chain of galaxies in Coma Berenices in the northern spring sky.

This frames the spectacular region of the Milky Way near the direction of the galactic centre in Sagittarius.

And hereโ€™s a field (above) with the small Founder Optics Draco 62mm scope, framing the rich Sagittarius Starcloud punctuated with the small dark Ink Spot Nebula, all below the bright Lagoon and Trifid Nebulas. 

This panorama extends for about 240ยบ along the northern half of the Milky Way, from Orion at left, to Sagittarius at right, and centered on the Galactic Equator.

In autumn the Milky Way is up all night. So I used a simple star tracker, the MSM Nomad reviewed here on my blog, and a 28-70mm lens at 35mm to shoot a panorama from dusk to dawn along the Milky Way โ€” from the summer stars of Sagittarius and Cygnus (at right, above), through the autumn constellations overhead in Cassiopeia and Perseus (at centre), and down into the pre-dawn sky with the winter stars in and around Orion (at left). 

A Bonus Aurora from Arizona 

I was just north of the Mexican border, at a latitude 32ยฐ North, more than 20ยฐ farther south than at home in Alberta. But what should appear in my sky but โ€ฆ aurora! 

A selfie of me observing the great red aurora of October 10, 2024, from southern Arizona.

On October 9, and then again more so on October 10, a great solar storm brought Northern Lights down to me. And indeed across all of Canada and the U.S. The result for me was a red glow to the north โ€” the tops of distant auroral curtains I would have seen filling my sky at home. 

A time-lapse of an Arizona aurora, using a 15mm wide-angle lens shooting nearly 400 forty-second exposures. View it in-line here. Enlarge to a full screen view. There is no sound.

Above is a time-lapse video of the aurora that night, from a camera aimed due north for four hours. The red curtains come and go through the night.

This is a 360ยฐ panorama covering the entire sky and extending up to the zenith at centre, capturing a rare SAR arc across the Arizona sky in the pre-dawn hours of October 11, 2024.

The remarkable feature that night, October 10/11, was not the aurora, but what is called a SAR (Stable Auroral Red) arc that persisted all night. It appeared as a diffuse red band across the sky, created by heat energy leaking into the upper atmosphere during the solar storm. SAR arcs can accompany an aurora but are not auroras themselves. 

This panorama takes in a rare confluence of skyglows in a colourful dawn sky.

By dawn the next morning, now October 11, the tall Zodiacal Light was prominent alongside the magenta SAR arc to the north (left) and the winter Milky Way to the south (right). Thereโ€™s even a short pillar of light that might be an aurora fragment, or the tail of the comet!  

The Comet Returns 

However, toward the end of my 11-night marathon of deep-sky imaging, the bright head of the comet was to be rising into the evening sky for Part 2 of its apparition. Below is a shot from the evening of October 11, my last at Quailway. Yes, there it was, just above the Chiricahua Mountains. But it was a blip, barely visible in binoculars and to the camera. I had hoped for more. 

This is Comet Tsuchinshan-ATLAS (C/2023 A3) at far right, barely visible emerging into the evening sky and low in the twilight, on October 11, 2024. This view includes Venus at left. Venus was obvious; the comet was not!

With the Moon now waxing into the evening sky, my plan was to head back north, stopping at scenic spots on the trip home, to catch the comet over moonlit landscapes to the west in the dusk sky.

My first two nights, October 12 and 13, at the VLA Radio Observatory near Socorro, New Mexico, then farther north near Canyon de Chelly, Arizona, were both beset by clouds to the west. From images posted on-line, I knew the comet was improving. But it was eluding me. 


October 14 & 15 โ€” at Arches National Park, Utah

The next stop was Arches National Park in Utah, which I last visited in April 2015. The first nightโ€™s forecast for October 14 also looked to be cloudy. But October 15 was supposed to be clear. So I extended my stay by an extra night, thinking that might be my only chance.ย 

As it turned out October 14 was fabulous (below). The comet was easily visible to the unaided eye as a classic comet in the west. I pointed it out to folks walking by at the Windows Arches area. And I could hear other people commenting on it. At last a comet! One that anyone could see โ€” though it helped to be at a clear sky site like Arches. 

Comet Tsuchinshan-ATLAS at its finest in the evening sky, two days after its closest approach to Earth, and with it sporting a 10ยบ- to 15ยบ-long dust tail, and a narrow anti-tail pointed toward the horizon.

By then the Moon was well advanced in age to a bright gibbous phase, so the sky was by no means dark. It was deep blue in photos.

Still the comet showed up brilliantly; it had blossomed a lot in a couple of nights. Above, I framed it beside moonlit Turret Arch.

Below is a scene from the next night, October 15, my โ€œback-upโ€ night. The comet was certainly performing well after all. Even in the moonlight. In binoculars the tail stretched for the same length as the camera recorded it, some 15ยฐ. 

This is a telephoto close-up Comet Tsuchinshan-ATLAS over the red rocks of Arches National Park, Utah, on a superb moonlit night, October 15, 2024.

Indeed, that was my last view of the comet for a while, as clouds prevented any more shooting on the rest of my journey north through Idaho and Montana.ย I even hit a snowstorm in southern Montana.


Late October โ€” Back at Home in Alberta

But the comet was not done yet! Through October, while it receded from us in distance, it climbed higher into our sky, placing it into a dark sky with the Moon now out of the way.ย 

This is Comet Tsuchinshan-ATLAS in a wide-angle nightscape scene over the Badlands of Dinosaur Provincial Park, Alberta, on October 23, 2024.

On October 23, a short trip out to Dinosaur Provincial Park east of home allowed me to shoot the comet over the Alberta Badlands landscape, beside the setting summer Milky Way. 

This is a telephoto lens framing of Comet Tsuchinshan-ATLAS in Ophiuchus on the night of October 30, 2024 near several large star clusters. The field of view is 15ยบ by 10ยบ so the tail extends for about 6ยบ to 8ยบ.

By a week later, on October 30, the comet had diminished in size and brightness, but still looked like a classic comet, here framed in a telephoto close-up as it passed near some bright star clusters. This was from my front yard. The chase was over. 

Clouds and a trip to Norway starting November 4 prevented more opportunities to shoot the comet. (My travel schedule also kept me from writing this blog until now!)

It had been a good chase over a month, yielding images I was happy with. The photos from Utah and Arizona I could not have taken at home, even if the skies had been clear during the cometโ€™s prime-time. (They werenโ€™t!) And it was great to finally get back to my favourite haunts in southern Arizona and New Mexico after an absence of seven years.

In all, Comet Tsuchinshan-ATLAS provided a fine finale to what has been a superb year of stargazing events and celestial sights. 

โ€” Alan, December 9, 2024 โ€” AmazingSky.com ย 

Testing the MSM Nomad Tracker


The new star tracker from Move Shoot Move improves upon their original model, eliminating its flaws to provide a reliable and compact tracker. 

A few years ago the start-up company Move Shoot Move (MSM) introduced a low-cost (about $250), compact star tracker they called the Rotator. Like all other star trackers, the Rotator allowed a camera to follow the turning sky for untrailed, pinpoint stars in long exposures. 

Trackers are essential for rich Milky Way images, and are great for nightscapes, for shooting the sky, blended with untracked shots of the ground, as I show in examples below.

The original Rotator (L) and new Nomad (R). The Nomad is even smaller than the Rotator.

Out with the Old โ€ฆ

The original Rotator went through a couple of design changes during its lifetime. I tested the last versions to be marketed, using three different sample units I either purchased or were sent to me by MSM. (My reviews appeared in 2019 on my blog here, and in the June 2021 issue of Sky & Telescope magazine.) 

The bottom line is that I found all the samples of the Rotator I tested to be unreliable for accurate tracking, indeed for tracking period, as units would sometimes not start tracking for a few minutes, or just stop tracking mid-shoot and then restart intermittently. Getting a set of untrailed exposures was a hit or miss affair. 

But with a cost lower than most other trackers on the market (ostensibly, as explained below), a pocketable compact size, and with endorsements from notable nightscape photographers, the original Rotator garnered a loyal following of fans. I was not one of them.

MSM obviously recognized the design flaws of the Rotator, because in early 2024 they replaced it with an all-new model, dubbed the Nomad. It works! 

The Nomad on the Benro 3-Way Head, with Laser and Polar Scope, and with a camera and 135mm lens. The ball head is not one from MSM.

I purchased a unit in January 2024 when the Nomad came out, and have used it extensively and successfully over the last few months. I found it has addressed all the serious flaws of the Rotator.

Polar Alignment Accessories

With a weight of about 400 grams, the Nomad is about 70 grams lighter than the old Rotator. It is one of the lightest and smallest trackers on the market, a benefit for those wanting to hike to remote nightscape sites, or pack gear for airline travel. (I took my Nomad to Australia this year; one result is below, shot with the Nomad.)

This frames the spectacular area of the southern Milky Way from Centaurus at left, to Carina at right, with Crux, the Southern Cross, at centre. This is a stack of 8 x 4-minute exposures with the Canon RF28-70mm lens at 48mm and f/2.8, on the Canon Ra at ISO 800. All on the MSM Nomad tracker.

However, unlike the popular Star Adventurer 2i and Mini trackers from Sky-Watcher, the Nomad, like MSMโ€™s older Rotator, does not have a polar alignment scope built in, just a peep sight hole. That makes it easier for MSM to fit a tracker inside a compact box. 

And yet, I feel some form of polar alignment aid (not just a peep sight) is essential if a tracker is to follow the sky accurately. Like the Rotator, the Nomad can be purchased with two add-on choices (shown below): 

โ€ข a 5 mw green laser pointer, 

โ€ข and an optical polar scope โ€ฆ

โ€ฆ each of which attaches to the side of the Nomad as outboard accessories. I purchased both, bundled with the Nomad as โ€œBasic Kit Cโ€ for $309 U.S., and find both accessories useful. 

NOTE: When shopping at the MSM website donโ€™t be fooled by what looks like temporary sale prices. The prices are always marked down, though MSM does offer coupon codes now and then for genuine discounts. I’ve always found MSM’s delivery by parcel post prompt, and in my case, shipments came from a warehouse in Canada, not China. 

As with the Rotator, the need to add essential accessories makes the Nomad more expensive and more complex to pack than buyers might think. And it can be more complex to initially set up than imagined, not helped by the lack of any instructions. (I’m told by MSM that a downloadable PDF sheet is being prepared.) In place of factory-supplied instructions, MSM depends on its YouTuber fans to provide tutorials. 

It took me a moment to figure out how the laser attaches to the Nomad โ€” it does so by replacing the black cap that comes on the laser with a supplied threaded red cap, so the laser can screw into the peep hole on the Nomadโ€™s body that is covered by yet another cap you remove โ€” but donโ€™t lose it, as you might need it. 

The optical polar scope attaches by way of an included clamp held onto the Nomad by the laser, or by the removable threaded cap (so you will need it if you arenโ€™t using the laser, but it is easily lost). 

Out of the box I found I had to adjust the beam of the laser (using the two tiny set screws on the laser) so the beam exited straight out the laser and up the peep hole in the Nomadโ€™s case. 

Once collimated, the laser pointer has proved to be an accurate and convenient way to polar align, especially for shooting with wide-angle lenses. (Keep in mind, green laser pointers over 1 mw are illegal in some jurisdictions.)

The laser uses a removable and rechargeable 3.7-volt battery, and comes with a little USB-powered charger. The laser’s battery has lasted for months of momentary use. The laser works briefly in winter when it is warm, but as soon as it gets cold, as is true of most laser pointers, it refuses to lase! 

However, for the more accurate polar alignment needed when shooting with telephoto lenses (an example is above), and for winter use, I prefer to use the optical polar scope, with the laser a handy complement just to get close to the pole. 

The polar scope has a reticle etched with star patterns for both the North and South Celestial Poles. I found the latter worked well in Australia. The mounting clamp held the polar scope securely and consistently well centered, another welcome improvement over the polar scope clamp supplied with the Rotator, which could wiggle around. 

Polar scope with its glow-in-the-dark Illuminator. The Nomad comes with an Arca-Swiss dovetail plate bolted onto the bottom edge, for attaching it to a tripod head or to the optional MSM Wedge.

The polar scope does not have an illuminator LED. Instead, it comes with a novel phosphorescent cap which you hit briefly with white light so it glows in the dark. 

Placed over the front of the polar scope, it lights up the field allowing the reticle to be seen in silhouette. While it works fine for sighting Polaris, the bright field can make it hard to see the faint stars in Octans around the South Celestial Pole. 

The Nomad on the Benro 3-Way Geared Head, using the Arca-Swiss attachment plate. Another method of mounting the Nomad to the Benro is shown below.

To aid polar alignment I purchased the Benro 3-Way Geared Head, also sold by MSM but available from many sources. Its geared motions make it easy to aim the trackerโ€™s rotation axis precisely at the pole and hold it there solidly. 

The Benro accepts standard Arca-Swiss mounting plates, so Iโ€™ve found it a useful head to have for other purposes and gear combinations. It has replaced my old Manfrotto 410 3-axis head which uses a proprietary mounting plate.

However, MSM also sells its own latitude adjustment Wedge which, at $90, is a cheaper alternative to the $200 Benro. Iโ€™ve not used the MSM Wedge, so I canโ€™t say how solid and precise it is. But the Wedge is lighter than the Benro head, and so may be a better choice when weight is a prime consideration. 

I would recommend either the Wedge or Benro for their fine adjustments of azimuth and altitude that are essential for easy, yet precise and stable polar alignment. 

Tracking Accuracy 

All-important is how well the Nomad tracks. When shooting with wide-angle lenses (14mm to 35mm) for nightscapes and wide Milky Way shots, the majority of images Iโ€™ve taken over the last few months, using exposures of 1 to 3 minutes, have been reliably well tracked, with pinpoint stars.ย 

The Nomad begins tracking right away, with no wait for gear backlash to be taken up, or for the drive mechanism to settle in. I also found no tendency for tracking to be better or worse with camera position, unlike the Rotator that seemed to work better with the camera aimed at one area of sky vs another. And the Nomad didn’t suffer from any stalls or moments when it just stopped in its tracks, again unlike the problematic Rotator.

20 consecutive 2-minute exposures with a 135mm lens, to show the variations in tracking accuracy. Tap on the image to download it for closer inspection.

As with any tracker, where you do see mistracking is when using longer lenses. I tested, and indeed have used, the Nomad with 85mm and 135mm telephoto lenses, as many owners will want to do, for close-ups of Milky Way starfields and for so-called โ€œdeepscapes.โ€ (An example of the latter is at the end.) The demo image above shows blow-ups of consecutive frames from the 135mm shoot of the Vulpecula/Sagitta starfield shown earlier.ย 

In those more demanding tests, as I demonstrate here, I found that typically about 50% to 60% of images (taken with 1- to 2-minute exposures) were tracked well enough to be usable. The longer the focal length used, or the longer the exposures, the more frames will be trailed enough to be unusable in an image stack. And a well-tracked frame can be followed by a badly tracked one, then the next is fine again. Thatโ€™s the nature of small drive gears.

As with other trackers, I would suggest that the Nomad is best used with lenses no longer than a fast 135mm. Even then, plan to shoot twice as many frames as youโ€™ll need. Half may need to be discarded. While I know some users will want to push the Nomad beyond its limits, I would not recommend burdening it with monster telephoto lenses or small telescopes. Like all other trackers, that’s not its purpose.

When there was mistracking it was usually in the east-west direction, due to errors in the drive mechanism, and not north-south due to flexure. (If it occurs, north-south drift is likely due to poor polar alignment.)

I found the Nomad did indeed turn at the sidereal rate to follow the stars, something I was never confident the Rotator actually did. 

While you might think a 50% success rate with telephotos is not good, in fact the Nomadโ€™s tracking performance is on par with other competing trackers Iโ€™ve used, from Sky-Watcher and iOptron. At wide-angle focal lengths the success rate proved closer to 100%.

So for a tracker as compact as the Nomad to perform so well is very welcome indeed. Itโ€™s the main area where the Nomad beats the old Rotator by a long shot! 

NOTE: While the MSM website mentions an “optional counterweight system,” as of my review’s publication date it is still being developed, MSM tells me. However, I don’t feel it will be necessary for the Nomad’s main purpose of wide-field imaging.

Mechanical Stability 

Another flaw of the old Rotator was that it had several single-point attachments that, under the torque of a turning camera, could cause the camera to come loose and suddenly flop down. 

The Nomad uses a ratcheted clamp to attach a user-supplied ball head to the tracker body, and that clamp has an additional safety set screw to help ensure the ball head does not unscrew itself as a camera turns. 

Iโ€™ve had no issues with cameras coming loose. Of course, the solidness of the ball head used will be critical as well. A large ball head can be better, but introduce some of the issues I report on below. 

While MSM offers its own ball head, I have not used it, preferring to use a couple of other ball and pano heads I like, and that I show in the images here. 

Simplicity of Operation

The Nomad improves upon the old Rotator by doing away with all its time-lapse features. You might think that eliminating features canโ€™t be an improvement, but in this case it is. 

I suspect few owners used the Rotatorโ€™s preset functions for slowly turning a camera along the horizon while firing the camera shutter between each incremental time-lapse move (the very function that gave the company its name!). The Rotatorโ€™s options for creating time-lapses were confusing to set up and limited in their choice of speeds. A serious time-lapse photographer would never use it. 

(If you do want a tracker with time-lapse motion-control capabilities the Star Adventurer Mini works well. Its WiFi connection and mobile app allows a user to set all the factors needed for a good time-lapse: interval, angle increment, number of frames, and length of shoot.) 

Instead, MSM has focused the Nomad on being just a star tracker, and I think wisely so. Its only controls are a three-position S-OFF-N switch, for using the Nomad in either the southern or northern hemisphere. It worked very well “Down Under,” with the exception noted below. 

There is no solar or lunar drive rate, unnecessary in a tracker, and also no half-speed rate for nightscapes, used to lessen star trailing while also minimizing ground blurring. Iโ€™ve never liked using trackers at such a compromise half-speed rate, so I donโ€™t miss it. 

Using the optional V-Plate described below, I have used the Nomad to take tracked Milky Way panoramas, as shown here. It has worked very well for that purpose, with it easy to switch the tracking on (for the sky) and off (for the ground). 

This is a 200ยฐ panorama of the arch of the northern Milky Way rising over Dinosaur Provincial Park, Alberta. Shot with the Nomad, with a blend of an untracked panorama for the ground and tracked panos for the sky.
The gear used to take the panorama above, including the Alyn Wallace V-Plate, supporting an Acratech 2-axis pan head. The Nomad is ON here, set to N. Below the power switch is the USB-C port for charging and external power.

My only criticism is that the power switch is a little mushy and perhaps easy to slide on by mistake when it is packed in a bag.

An LED for each of the N and S directions glows red to indicate the power is on and the direction chosen, handy to help prevent you from choosing the wrong direction by mistake. 

The Nomad is powered by an internal lithium battery that charges from any 5-volt USB charger (the Nomad comes with a USB-C cord, but no charger). The Nomad takes about 2.5 hours to charge to full and runs for 6 to 7 hours of continuous tracking at room temperatures. A second LED by the USB port glows yellow when the Nomad is charging, and green when it has fully charged. 

In practice the Nomad has lasted for several nights of shooting on one charge. When the battery level is low, the red LED for the other direction begins blinking. As a backup in the field, the Nomad can be powered via its USB-C port by any external 5-volt power bank.

Collisions 

The Nomad hasnโ€™t been without issues, though the main problem Iโ€™ve had I canโ€™t, in fairness, blame on the Nomad. 

Due to the Nomadโ€™s small size and shape, ball heads sit close to the Nomad body. Locks and clamps sticking out from ball heads can collide with the Nomad, or with the Benro head, as it rotates the ball head. Here I show how a collision can occur when aimed up at the zenith. 

Showing the ball head colliding with the Benro when aimed high.

But collisions can also occur when aimed at the Celestial Pole. I ran into that issue in Australia, where many of the wide-field targets in the Milky Way (such as the field in Carina and Crux shown earlier) lie close to the South Celestial Pole. 

A camera aimed toward the Celestial Pole (either South or North) is more likely to collide with the Nomad than when a camera is aimed toward the sky opposite the Pole. 

As I show above, one night when tracking targets in Carina I found the ball head had jammed against the Nomad, seizing its motion. As I feared, that caused something inside the Nomad to come loose. 

After the collision incident no frame was well-tracked. The Nomad was wandering all over the place!

From then on it failed to track well for any shots. The drive was wobbling the stars in random directions. No frame was usable. The Nomad was now out of commission, not a welcome prospect when you have traveled to the other side of the world to shoot the sky. 

The access hole with a handy adjustment screw that fixed the issue.

What was the solution? There was only one point of adjustment accessible to users, a mysterious hole on the side of the tracker with a small hex screw at the bottom. This is normally covered by a rubber plug, though that was either missing on arrival or got lost along the way from my unit. Upon inquiry, MSM told me the screw is for use just at the factory, for a final adjustment of the gear and bearing distance.

But in my case, tightening it slightly seemed to do the trick, restoring normal tracking. However, my unit still tends to make intermittent clicking sounds now and then, though it seems to track well enough again. 

The lesson here is donโ€™t let gear collide with the Nomad. It likely has no internal clutch, making it unforgiving of being jammed.

Collision Avoidance

How do you avoid collisions? What I should have used in Australia was MSMโ€™s optional V-Plate designed by the late and sadly missed Alyn Wallace. 

I bought one a couple of years ago, but never thought to bring it with me on the Australia trip. As I show above, the V-Plate allows for much more freedom to aim a camera, either toward the Poles or straight up (as I show above), or low in the sky 180ยฐ away from the Pole, without fear of the ball head hitting other components. 

The V-Plateโ€™s shortcoming is that, despite cranking down the levers that hold it in position, it can still slip under the weight of a heavy camera sitting on the diving-board-like platform supported only on one end. The V-Plateโ€™s locks are not as solid and secure as they should be. But with care it can work well. And you need buy only the V-Plate; not the Z-Plate.

I should note that since I got my V-Plate, it has been upgraded with a larger lever handle to aid tightening the tilt lock. However, it really needs another support point on the tilt adjustment, so it can’t move as readily under load.

In addition, MSM now offers a taller Arca-Swiss mounting block as an option, to replace the plate that comes bolted onto the Nomad with two Torx screws. That optional riser block moves the Nomad farther from the Wedge or Benro head, helping to prevent some collisions. By putting more space between the Nomad and the Benro head, the riser block makes it easier to get at the small locking clamp on the V-Plate’s rotation axis. But …

Shortly after I first published this review, a loyal reader (thanks, John!) pointed out his method of placing the Nomad on the Benro, with the Nomad turned 90ยฐ to the way I pictured it earlier. As I show below, this places the Benro’s lock knob on the side of the Nomad, not back. The benefit is that the V-Plate’s azimuth lock lever is now more accessible and well-separated from the Benro. That method makes the taller riser block unnecessary.

Here’s a reader-suggested alternative method for mounting the Nomad and orienting the Benro head that puts more space between the V-Plate and Benro, for ease of adjustment.

Even with this alternative method, the V-Plate tends to block the laserโ€™s beam, as does a camera once it is mounted. The polar scope can also be blocked. Itโ€™s an example of how one MSM accessory can interfere with another accessory, perhaps requiring yet another accessory to solve! 

In practice, with the V-Plate installed, polar alignment often has to be done before attaching the camera or setting up the V-Plate to the desired orientation. When adding the camera, care has to be taken to then not bump the Nomad off alignment. Thatโ€™s why I like the Benro head as a stable platform for the Nomad, despite its extra weight. 

As I illustrated earlier, the V-Plate is also an essential accessory for shooting tracked-sky Milky Way panoramas, as it allows a camera to be turned parallel to the horizon from segment to segment while it also tracks the sky.

A “deepscape” of the Sagittarius starclouds over Mt. Blakiston, in Waterton Lakes National Park, Alberta. This is a blend of two exposures: a single untracked 2-minute exposure at ISO 1600 for the ground, and a single tracked 2-minute exposure at ISO 800 for the sky, taken immediately after, with the Nomad tracker motor now on. With a 28-70mm lens at 70mm, on the rig shown.

Recommendations 

So, as with the Rotator, when buying a Nomad, plan on adding several โ€œoptionalโ€ accessories to your cart. They can, in fact, be essential. 

However, they can add another $150 (for V-Plate + Wedge + riser block) to $250 (V-Plate + Benro head + riser block) to the total. These are in addition to the cost of the polar alignment aids offered in the various Basic bundles. I like having both the laser and polar scope, but for shooting just wide-angle nightscapes, the laser alone will do.

The cost of accessories makes the Nomad not quite the low-cost tracker you might have been sold on, nor as self-contained and compact as it first appears. Just choosing what combination of gear to buy can be daunting for beginners. 

The Milky Way and its core region in Sagittarius and Scorpius over the Badlands of Dinosaur Provincial Park, Alberta. This is a blend of untracked exposures for the ground and tracked exposures for the sky, with the Canon Ra on the Nomad, with the Canon RF15-35mm lens at 20mm at f/2.8.

But when well-equipped, the little Nomad can work very well. Despite my run-in with a collision glitch, I can recommend the Nomad as a good choice for anyone looking for a solid, accurate, but portable tracker that can slip into any camera bag. 

Just make room in your bag โ€“ and budget! โ€“ for polar alignment aids, V-Plates, wedges, and ball heads to complete your tracking kit. 

And then donโ€™t let anything collide with the Nomad! 

โ€” Alan, June 27, 2024 – Revised June 28 / AmazingSky.com  

Nights at World Heritage Sites


I present a selection of new images taken at local World Heritage Sites, along with some advanced nightscape shooting tips.

I’m fortunate in living near scenic landscapes here in southern Alberta. Many are part of UNESCO World Heritage Sites that preserve regions of unique scenic and cultural significance. In early June I visited several to shoot nightscapes of starry skies over the scenic landscapes.

I also took the opportunity to experiment with some new shooting techniques. So I’ve included some tips and techniques, most of the advanced variety.


First up was Dinosaur Provincial Park.

The Milky Way and its core region in Sagittarius and Scorpius is here low over the Badlands landscape of Dinosaur Provincial Park, Alberta.

After nearly a month of rain and clouds, the night of May 31/June 1 proved wonderfully clear at last. I headed to a favourite location in the Red Deer River valley, amid the eroded badlands formations of Dinosaur Provincial Park, site of late-Cretaceous fossil finds.

The bright core of the Milky Way in Sagittarius would be in the south. With the night only three weeks before summer solstice, from the Park’s latitude of 50.5ยฐ N the sky would not get astronomically dark. But it would be dark enough to show the Milky Way well, as above in this framing looking south on the Trail of the Fossil Hunters.

However, May and June are “Milky Way Arch” months, at least for the northern hemisphere. The full sweep of the northern Milky Way, from Perseus in the northeast to Sagittarius in the southeast, then stretches across the sky โ€” high enough to be impressive, but low enough (unlike later in summer) to be framable in a horizontal panorama.

This is a 200ยฐ panorama of the arch of the northern Milky Way rising over the Badlands landscape of Dinosaur Provincial Park, Alberta.

To capture the arc of the Milky Way I shot a panorama โ€” in fact three:

  • one exposed for the ground
  • one exposed for the sky, but with the camera now tracking the sky to keep stars pinpoint
  • and a final sky panorama but with a specialized filter installed in front of the camera sensor to let through only the deep red light emitted by nebulas along the Milky Way
Rig for tracked panoramas with the MSM Nomad tracker

The image above shows my rig for taking tracked panoramas. The rectangular box is the little Nomad sky tracker from Move-Shoot-Move (MSM), here equipped with its accessory laser pointer to aid the “polar alignment” that is needed for this or any tracker to follow the turning sky properly.

A review of the MSM Nomad will be forthcoming (subscribe to my blog!). However, I’ve found it works very well, much better than MSM’s original Rotator tracker, which was entirely unreliable!

On top of the little Nomad is an Acratech pano head, so I can turn the camera by a specific angle between each pano frame, both horizontally from segment to segment, and vertically if needed when raising the camera from the ground pano to the sky pano.

The pano head is on a “V-Plate” sold by MSM and designed by the late, great nightscape photographer (and engineer by trade), Alyn Wallace. The V-Plate allows the camera to turn parallel to the horizon when on a tipped-over tracker. The entire rig is on a Benro 3-Axis tripod head (also sold by MSM, but widely available) that makes it easy to precisely aim the tracker for polar alignment and then hold it rock steady.

The H-Alpha Panorama rendered in monochrome

I’d taken many panos before using sets of untracked ground and tracked sky panoramas. New this night was the use a “narrowband” Hydrogen-Alpha filter to take a final pano that brings out the red nebulas. I used a filter from Astronomik that clips into the camera in front of the sensor. Such a filter has to be used on a camera that has been modified to be more sensitive to deep red light, as the Canon Ra shown below is (or was, as Canon no longer makes it).

While a modded camera brings out the nebulas, using an H-Alpha filter as well really shows them off. But using one is not easy!

Astronomik clip-in filters, the 12nm H-a on the right

The clip-in placement (unlike a filter in front of a lens) requires that the lens be refocused โ€” infinity focus now falls at the 3 to 6 metre point (the focus shift varies with the lens and focal length โ€” the wider the lens the greater the shift). With the image so dark and deep red, seeing even a bright star to manually focus on is a challenge.

Shifting the lens focus also changes the overall image size (called “focus breathing”) and often introduces more off-axis lens aberrations, again depending on the lens.

So, blending the H-Alpha pano (which I rendered out in monochrome, above) into the final stack is tough, requiring lots of manual alignment, image warping, BlendIf adjustments, and masking. This is where I added in the red colouration to taste. Careful here, as the “Saturation Police” patrolling social media will issue tickets if they judge you have exceeded their “speed limit.”

The complete panorama with Photoshop layers and adjustments

The final pano required a complex blend of image and adjustment layers, all applied non-destructively, so the many elements of the scene can be individually tweaked at any time.

The work was worth it, as the final pano records the deep red nebulas contrasting with the deep blue of a sky still lit partly by twilight, a magenta aurora to the north, and bands of green and yellow airglow, all above the earth tones of the Badlands. It is one of my favourite nightscape panoramas.

As a further note on software: For stitching panos I try to use Adobe Camera Raw first. It can work very well. But complex panos, especially taken with very wide lenses, often require the specialized program PTGui, which offers more choice of pano projection methods, cleaner stitching, and control of panorama framing and levelling.


Next up was Writing-on-Stone Provincial Park.

A week later, with the waxing Moon beginning to appear in the western sky and the promise of clear nights, I headed south to the 49th parallel borderlands of the Milk River and Writing-on-Stone Provincial Park, known as รรญsรญnai’pi to the Blackfoot First Nation who revere the site as sacred.

My plan was a framing of the galactic centre over the Milk River valley and distant Sweetgrass Hills in Montana, perhaps using the H-Alpha filter again. But clouds got in the way!

A 13-segment panorama of the landscape and sky just as the Sun sets over Writing-on-Stone Provincial Park (รรญsรญnai’pi) in Alberta.

When you are faced with a cloudy sky, you make use of it for a colourful sunset. I like shooting panoramas at such sites as they capture the grand sweep of the “big sky” and prairie landscape. Above is the scene at sunset.

A 14-segment panorama of the landscape and sky at sunset at Writing-on-Stone Provincial Park.

Above is the same scene a few minutes later as the Sun, though now set, still lights the high clouds with its red light, mixing with the blue sky to make purples. On the hill at right, a couple admires the sunset, adding a human scale to the vast skyscape.

This pano was with the Canon RF15-35mm lens at 15mm and the camera in portrait orientation to capture as much of the sky and ground as possible in a single-row pano.

A 13-segment panorama of the sandstone landscape in blue-hour twilight at Writing-on-Stone Provincial Park.

I finished the evening with another panorama, but using a Canon RF70-200mm telephoto lens at 70mm to zoom in on the Sweetgrass Hills in the deepening twilight.

For these panoramas, exposures were short, so I didn’t need to track the sky. I used another combination of gear shown above. An Acratech ball head sits atop another style of panorama head that has adjustable click stops to make it easy to move the camera from segment to segment at set angles. When the lighting is changing by the second, it helps to be quick about shooting all the pano segments. Such pano heads are readily available on Amazon.

That pano head sits atop an Acratech levelling head (there are many similar units for sale), an essential addition that makes it easy to level the pano head so the camera turns parallel to the horizon. Any tilt will result in a panorama that waves up and down, likely requiring fussy warping or cropping to correct. Avoid that; get it right in-camera!

A single-image portrait of a sunset sky with the waxing two-day-old crescent Moon amid colourful clouds over the prairie.

As the sky lit up, I also shot the crescent Moon above the sunset clouds and prairie scene. While the clouds made for a fine sunset, they did not clear off, thwarting my Milky Way plans this night. I headed back to Milk River, to travel farther west the next day.


From Writing-on-Stone I drove along scenic Highways 501 and 5 to Waterton Lakes National Park.

A nightscape scene under a twilight “blue-hour” sky, on the Red Rock Canyon Parkway in Waterton Lakes National Park, Alberta, looking west toward the sunset with the four-day-old crescent Moon.

After an initial cloudy night, I made use of the (mostly) clear night on June 10 to shoot twilight scenes with the now four-day-old crescent Moon in the evening sky. Here I wanted to play with another technique I had not used much before: focus stacking.

To keep exposures short (here to minimize the blurring effects of the constant wind at Waterton) you have to shoot at wide apertures (f/2 in this case). But that produces a very shallow depth of field, where only a small area of the image is in focus.

So I shot a series of six images, shifting the focus from near (for the foreground flowers) to far (for the mountains and sky). Photoshop has an Auto Blend function that will merge the images into one with everything in focus. I also shot separate images exposed for the bright sky, shooting a vertical panorama โ€” dubbed a “vertorama” โ€” moving the camera up from frame to frame.

I shot an additional short exposure just for the Moon, to prevent its disk from overexposing too much, as it did in the twilight sky images.

Twilight sky assembly and layers in Photoshop

So what looks like a simple snapshot of a twilight scene is actually a complex blend of focus-stacked ground images, panoramic sky images, and a single short image of the Moon replacing its otherwise overly bright disk. But the result better resembles what the eye saw, as single exposures often cannot record the range of brightness the eye can take in.

A nightscape scene under a moonlit sky, on the Red Rock Canyon Parkway in Waterton Lakes National Park, Alberta, looking back along Pass Creek to the south, with the Milky Way rising at left.

About an hour later, from the same location, I shot the other way, toward the Milky Way rising over Vimy Peak, but the sky still lit blue by moonlight. This, too, is a blend of focus-stacked ground and panorama sky images. But the camera was on a fixed tripod for exposures no longer than 15 seconds. So I didn’t use the tracker.

And here the longer exposures do pick up more (colours, fainter stars, and brighter ground detail) than was visible to the eye. Revealing more than the eye can see is the essence and attraction of astrophotography.

A vertical panorama of the moonlit spring sky with the Big Dipper and Arcturus over the jagged outline of Anderson Peak at the Red Rock Canyon area of Waterton Lakes National Park, Alberta.

Heading down the Red Rock Canyon Parkway, I set up the tracker rig for the darker sky, now that the Moon was nearly setting. I shot a vertical panorama, with two untracked ground segments and four tracked sky segments, to capture Arcturus and the Big Dipper over the iconic Anderson Peak.

Comparing without and with LENR โ€“ Lots of coloured specks without LENR! Tap to zoom up.

For all the images at Waterton and Writing-on-Stone I used the 45-megapixel Canon R5 camera, great for high resolution, but prone to noise, especially colourful thermal hot pixels. (See my review here.)

For all the long exposures I turned on Long Exposure Noise Reduction, a feature most cameras have. LENR forces the camera to take a “dark frame,” a second exposure of equal length, but with the shutter closed. The camera subtracts the dark frame (which records only the hot pixels) from the previous light frame. The final image takes twice as long to appear, but is much cleaner, as I show above. So a two-minute exposure requires four minutes to complete.

While there are clever ways to eliminate hot pixels later in processing (using Photoshop’s Dust and Scratches filter), doing so can blur details. I’ve long found that doing it “in-camera” always produces better results.

The Milky Way rising over the peak of Mt. Blakiston, in Waterton Lakes National Park, Alberta, Canada.

With the Moon now down, I turned the camera the other direction toward Mt. Blakiston, to capture the star clouds of the summer Milky Way rising behind the mountain, in an example of a “deepscape,” a nightscape with a telephoto lens. This is another technique I’ve not used very often, as the opportunities require good location planning and timing, transparent skies, and a tracker. Apps like ThePhotographersEphemeris coupled with TPE3D, and PlanItPro can help.

Deepscapes frame landscape fragments below some notable deep-sky objects and starfields, in this case a region with several “Messier objects” โ€” nebulas and star clusters well-known to amateur astronomers.

This was a blend of one untracked and one tracked exposure, again on the Nomad. Taking more frames for stacking and noise reduction, while a common practice, was not practical here โ€” at this focal length of 70mm the sky was moving enough that the mismatch between sky and ground would make blending tough to do.

And the reality is that today’s AI-trained noise reduction software (see my test report here) is so good, image stacking is not as essential as it once was.

For many of the Waterton images I used the Canon RF28-70mm lens, usually wide open at f/2. For the image below I used the RF15-35mm lens at its maximum aperture of f/2.8. (See my test report on these lenses here.)

The stars and clouds trail across the sky over Cameron Lake in Waterton Lakes National Park, Alberta, and Mt. Custer across the border in Glacier National Park in Montana.

On my final night in Waterton I drove the Akamina Parkway to Cameron Lake, located in extreme southwest Alberta on the borders with British Columbia and Montana. The glaciated peak to the south is Mt. Custer in Glacier National Park, Montana.

Again, I had hoped to get a deepscape of the photogenic starfields in Scorpius above Mt. Custer. But as is often the case at this site, clouds wafting over the Continental Divide defeated those plans. So Plan B was a set of long exposures of the clouds and stars trailing with the last light of the low Moon lighting parts of the scene. Chunks of ice still drift in the lake.

This is a blend of separate multi-minute exposures for the ground and sky, all at the slow ISO of just 100, and all untracked to purposely create the star trails, not avoid them.

So over a total of four nights at these wonderful World Heritage Sites, I was able to try out some new shooting techniques:

  • H-Alpha blending
  • Focus stacking
  • Deepscapes
  • As well as panoramas, both horizontal and vertical

Every nightscape outing is a learning process. And you have to be prepared to change plans as the clouds dictate. I didn’t get all the shots I had hoped to, but I still came away with images I was very pleased with.

I hope you enjoyed them. Clear skies!

โ€” Alan Dyer / AmazingSky.com

The Great Aurora Show of May 10, 2024


It has been many years since we were treated to an aurora as widely seen as the show on May 10, 2024. Here’s my tale of the great display.

As the sky darkened around the world on May 10/11, 2024, sky watchers in both the northern and southern hemispheres were amazed to see the sky lit by the deep reds, greens and pinks of a massive display of aurora. For me, this was my first Kp8 to 9 show (to use one measure of aurora intensity) in more than 20 years, back in the film era!

Throughout the day, aurora chasers’ phones (mine included) had been beeping with alerts of the arrival of a major solar storm, with the usual indicators of auroral activity pinned to the top of the scale.

A NOAA satellite’s eye view of the ring of aurora May 10/11, showing it south of me in Alberta, and across the northern U.S. People in the southern U.S. saw it to their north.

As I show below, the graphic of the intensity of the band of aurora, the auroral oval, was lit up red and wide. This was a night we didn’t have to chase north to see the Northern Lights or aurora borealis โ€” they were coming south to meet us (as I show above).

Observers in the southern hemisphere had the normally elusive aurora australis move much farther north than usual, bringing the Southern Lights even to tropical latitudes in Australia, South America and Africa.

The cause was a massive sunspot group on the Sun which had let off several intense solar flares.

Sunspot group 3664 was so big it could be seen with the naked eye, using solar eclipse glasses. Photo courtesy NASA.

The flares had in turn blown off parts of the Sun’s atmosphere, the corona, that anyone who saw the total eclipse a month earlier had admired so much. But a month later, the corona was being blown our way, in a series of Coronal Mass Ejections (CMEs), to collide with Earth.

A movie of six CMEs blasting toward Earth, captured by the SOHO satellite. Courtesy NASA/ESA.

As it happened I was scheduled to give a community talk in the nearby town early in the evening of May 10, on the topic of The Amazing Sky! Watching the indicators, I could more or less promise the audience that we would indeed see an amazing sky later that evening as it got dark.

Post talk, I hurried home to get the cameras ready, choosing to forgo more hurried driving out to a scenic site in southern Alberta, for the convenience of shooting from my rural backyard. As the sky darkened, the clouds were lit purple, and curtains of aurora appeared in the clear patches.

Clouds and aurora in twilight with the 11mm TTArtisan full-frame fish-eye lens.
A bright arc of aurora shining through the purple clouds, with the 7.5mm TTArtisan circular fish-eye lens.

Something big was going on! This was promising to be the best show of Northern Lights I had seen from home in a year. (Spring 2023 had three great shows at monthly intervals, followed by an aurora drought for many months. See The Great April Aurora.)

A selfie at the start of the great aurora show of May 10, 2024.

I shot with four cameras (a Canon EOS R, Ra, R5 and R6) โ€” two for time-lapses, one for real-time movies, and one for still images. I used the latter to take many multi-image panoramas, as they are often the best way to capture the wide extent of an aurora across the sky.

The arc of aurora in purple and white across the northern sky from home in Alberta at the start of the great display (about 11:30 p.m. MDT).

Early in the evening the arc of aurora wasn’t the usual green from oxygen, but shades of purple, pink, and even white, likely from sunlit nitrogen. The panorama above is looking north toward a strangely coloured arc of nitrogen (?) aurora.

Then after midnight a more normal curtain appeared suddenly, but toward the south, brightening and rising to engulf much of the southern sky and the sky overhead.

Looking south with the 15mm wide-angle lens.

It is at local midnight to 1 a.m. when substorms usually hit, as we are then looking straight down Earth’s magnetic tail, toward the rain of incoming aurora particles bombarding the Earth. During a substorm, the rain turns into a deluge โ€” the intensity of the incoming electrons increases, sparking a sudden brightening of the aurora, making it dance all the more rapidly.

This is a 300ยฐ panorama of my home sky now filled with colourful curtains.

As the aurora explodes in brightness it often swirls up to the zenith (or more correctly, the magnetic zenith) to form one of the sky’s greatest sights, a coronal outburst. Rays and beams converge overhead to form a tunnel effect. It is jaw-dropping.

I’ve seen this many times from northern sites such as Churchill and Yellowknife, where the aurora often dances straight up. And from my latitude of 51ยฐ N in western Canada, the aurora does often come down to us.

But this night, people at latitudes where, at best, the aurora might be seen just as a glow on the horizon, saw it dance overhead in a corona show to rival the solar eclipse, and that other corona we saw on April 8!

This is a panorama of a substorm outburst creating an overhead corona with rays converging to the magnetic zenith (south of the true zenith), and amid clouds. The rays show a rich mix of oxygen greens and reds, as well as nitrogen blues blending to create purples. Some greens and reds are mixing to make yellows.

Yes, the long exposures of aurora photos (even those taken with phone cameras) show the colours better than your eye can see them (insensitive as our eyes are to colour in dim light). But this night portions of the arcs and rays were bright enough that greens and pinks were easily visible to the naked eye.


This is a single 9-second exposure of the peak of a bright outburst at 1 a.m. MDT. It was with the Laowa 7.5mm circular fish-eye lens at f/2 on the Canon R5 at ISO 800. It is one frame from a time-lapse sequence.

At its peak the show was changing rapidly enough, I couldn’t get to all the cameras to aim and frame them, especially the movie camera. The brightest outburst at 1 a.m. lasted just a minute โ€” the time-lapse cameras caught it. The sequence below shows the view in 9-second exposures taken consecutively just 1 second apart.

This series shows a brief outburst of bright aurora at the magnetic zenith overhead. The time between these 7 consecutive 9-second exposures is only 1 second, so this bright outburst did not last long (little more than a minute). With the TTArtisan 7.5mm f/2 fish-eye lens on the Canon R5. Click or tap to enlarge to full screen.

Here’s another sequence of frames taken as part of a time-lapse sequence with the 11mm lens. It shows the change in the aurora over the 80 minutes or so that it was most active for me at my site.


The time between these 12 images is usually 8 minutes, though to include some interesting activity at a bright outburst, the interval is 5 minutes for three of the images around 1 a.m. Each is a 7- or 9-second exposure taken as part of a time-lapse sequence using the 11mm TTArtisan lens at f/2.8 on the Canon R at ISO 800 or 1600.

Shooting time-lapses with fish-eye lenses captures the show with a minimum of attention needed (except to adjust ISO or exposure times when the aurora brightens!). I could use the still camera (with the Laowa 15mm f/2 lens) to take individual shots, such as more selfies and home shots.

This is a single 8-second exposure with the Laowa 15mm lens at f/2 on the Canon Ra at ISO 800. Another camera taking a time-lapse is in the scene. I had four going this night.

As colourful as the aurora was at its best between midnight and 1:30 a.m., I think the most unique shots came after the show had subsided to appear just as faint rays across the north again, much as it had begun. To the eye it didn’t look like much, but even on the camera’s live screen I could see unusual colours.

I took more panoramas, to capture one of the most unusual auroral arcs I’ve even seen โ€” a blue and magenta aurora across the north, similar to how the night started.

This a stitch of 11 segments, each 13-second exposures, with the Laowa 15mm lens at f/2 on the Canon Ra camera at ISO 800, and turned to portrait orientation. Processed in Camera Raw and stitched with PTGui.

The colours may be from nitrogen glowing, which tends to light up in blues and purples, especially when illuminated by sunlight at high altitudes. At 2 to 2:30 a.m. the Sun might have been illuminating the aurora at a height of 150 to 400 km, and far to the north.

I’d seen blue-topped green auroras before (and there’s a green aurora off to the west at left here). But this was the first time I’d seen an all-blue aurora, no doubt a product of the intense energy flowing in the upper atmosphere this night. And the season and my latitude.

The panorama is a spherical projection spanning 360ยบ, and reaching to the zenith 90ยฐ high at centre. This a stitch of 20 segments, each 13-second exposures, with the Laowa 15mm lens at f/2 on the Canon Ra camera at ISO 800, and turned to portrait orientation. Processed in Camera Raw and stitched with PTGui.

The weirdest aurora was at 2:30 a.m., when in addition to the blue rays of nitrogen, an odd white and magenta patch appeared briefly to the south. What was that??

The lesson here? During a bright show do not go back to sleep when things seem to be dying down. Interesting phenomena can appear in the post-storm time, as we’ve learned with STEVE and other odd red arcs and green proton blobs that we aurora photographers have helped document.

I end with a finale music video, mostly made of the time-lapses I shot this night.

Enjoy!

Bring on more aurora shows as the Sun peaks in activity, perhaps this year. But the best shows often occur in the 2 or 3 years after solar max. So we have several more years to look forward to seeing the Lights dance in our skies.

Watch in full screen and in 4K if you can. For all the tech details click through to YouTube and check the description below the video.

Thanks and clear skies!

โ€” Alan, May 18, 2024 amazingsky.com

The Total Eclipse of 2024 โ€” The Video


I present a two-minute video set to music of the April 8, 2024 total solar eclipse.

In my previous blog Chasing the Cross Continental Eclipse I told the tale of my chase to see the total eclipse of the Sun. I ended up under mostly clear skies in the Eastern Townships of Quรฉbec, Canada, not Texas, my original destination.

Here I present the result of shooting with four cameras that afternoon, taking still images, time-lapses, and a 4K movie.

Be sure to watch in 4K!

The site worked out very well, as the lower Sun in eastern Canada lent itself to views framing the eclipse over a landscape below, in this case a very wavy lake. But I was lucky to have open water as other lakes in the area were still frozen.

My post-eclipse selfie at the Lac Brome site in Quebec for the April 8, 2024 total eclipse of the Sun.

As it was, a snow storm a few days earlier left lots of snow in the area to be included in my post-eclipse selfie.

The description below the video on YouTube provides lots of information about the images used in the video. Click through to the video’s page on YouTube to learn more.

This was only the third total solar eclipse I’ve seen from Canada, after February 26, 1979 from Manitoba, and August 1, 2008 from the air out of Cambridge Bay, Nunavut in the Canadian Arctic. The next total eclipse from Canada passes over my home in Alberta. But it is not until August 22, 2044!

โ€” Alan, April 28, 2024 โ€” AmazingSky.com

Chasing the Cross-Continental Eclipse


I had always planned to drive to the April 8, 2024 total eclipse of the Sun. But to where? I ended up on the other side of the continent than originally planned.

It is not often the path of the Moonโ€™s shadow crosses your home country, let alone continent. Only once before in recent years, on August 21, 2017, did the narrow shadow path pass near enough to my home in Alberta to allow me to drive to a total eclipse. They almost always require flying. 

Packed and ready to hit the highway for a long eclipse trip.

Yes, while I could drive to the April 8, 2024 eclipse, it was going to demand a much longer drive than in 2017. But driving allowed me to take a carload of telescope and camera gear. So that was the plan. 

My destination was San Antonio, Texas. Thatโ€™s where I had made a hotel booking more than a year earlier. The weather prospects in Texas were forecast to be best (at least according to the long-term averages) of any locations along the path in the U.S. or Canada. (I did not want to drive into Mexico.) 

On March 30, with some trepidation, I set out down I-15 heading south. I got as far as Great Falls, Montana, my stop for night one. But it was to be a move in the wrong direction.

The forecast for Eclipse Day as of March 30. Blue is bad; white is good!

The various long-range weather models were all agreeing, even 10 days in advance, that Texas (covered in blue above) was looking poor for eclipse day. But eastern Canada looked good! That was the exact opposite of what had been expected. 

So on Easter Sunday, I turned around and headed north, crossing back into Canada at a lonely border post in southwest Saskatchewan. 

I proceeded east along the TransCanada, Highway 1. I decided against a route across the northern U.S. and around the southern end of Lake Michigan, to avoid severe weather forecast for the middle of the U.S. 

One of my daily Facebook travelogue posts with a beer of the day.

Along the way I posted my beer-du-jour travel reports, as above from Day 8, that day from within the shadow path at last!

I also stopped at the only total eclipse site, of the 16 I had seen previously, I have ever been able to re-visit. On February 26, 1979 I and a small band of friends from Edmonton viewed the mid-winter eclipse (the last one visible from southern Canada) from a median road (Firdale Road as it is now called) on the TransCanada Highway near Carberry, Manitoba. I found the spot again, where I saw (and shot with my Questar telescope) my first total eclipse of the Sun. 

However, a day after entering Ontario, the bad weather caught up with me, forcing an extra night north of Lake Superior while the only highway across the region, Highway 17, was cleared of snow and re-opened at Wawa, the usual cross-Canada choke point. 

My new destination (after abandoning the site in the Texas Hill Country) was to be southern Ontario. 

However, as eclipse day approached and the weather predictions became more precise, it was apparent that Ontario would also be under some cloud. Southern Quรฉbec was looking better. So the Eastern Townships became my new Plan A site! I was running out of time!

Using the TPE app to check the Sun’s location once on site, the day before the eclipse.

I arrived on site in Quรฉbec with only a day to spare to check out the location I had found by exploring Google maps. 

With the Sun lower in the mid-afternoon sky in Quรฉbec compared to the high-noon Sun in Texas, I decided to shoot a wide-angle scene of the eclipse over a lake, preferably with open water, not ice! That required a site with public parking on an eastern lakeshore.

The site I found, then checked out on April 7, was on Lac Brome. It proved ideal โ€” except for the thin cloud that was now predicted to drift through during the eclipse. 

Sure enough, thatโ€™s just what happened. The cloud detracted from the eclipse only in preventing long-exposure images recording the outermost streamers in the Sunโ€™s atmosphere. 

A wide-field view of the eclipse of the Sun, taking in the bright planets Jupiter (at top) and Venus (below) that were easily visible to the unaided eye during totality.

I could have sought out clearer skies by going even farther east, but I was in a crunch for time and hotel rooms! As it was I was able to get rooms everywhere I wanted and at normal โ€œnon-eclipseโ€ rates! 

A panorama of the lakeside parking area at Lac Brome prior to the eclipse.

The Lac Brome site filled with cars during the day, with people from Quรฉbec and Ontario, but also from Alberta, and from Pennsylvania, Massachusetts and Maine โ€“ at least those were the homes of the folks I enjoyed meeting on eclipse day. 

Everyone had a great time and had a superb eclipse experience. 

The total eclipse of the Sun over the waters of Lac Brome, in the Eastern Townships of Quebec, Canada. The twilight colours come from sunlight from outside the shadow path.

The lunar shadow arrived from the southwest, from the direction of the Sun, appearing as a dark cloud racing toward us. At the end of the eclipse the sky brightened first in that same direction, as the trailing edge of the shadow shot up across the sky. The clouds helped make the shadow edge more visible. 

A time-lapse of the arrival and departure of the lunar shadow, made of 1200 frames each 1 second apart.

I shot with five cameras, just as I had done in 2017, possible only because I drove. 

The main rig was my faithful Astro-Physics Traveler, a 105mm refractor telescope the company owner designed for his personal use at the 1991 eclipse in Mexico. 

My main eclipse rig, with a 60mm visual scope on the 105mm photo scope, on an equatorial tracking mount.

My Traveler, bought in 1992, has lived up to its name, having now been to six central solar eclipses: the annular eclipses of 1994 (Arizona) and 2023 (Utah), and the total eclipses of 1998 (Curaรงao), 2012 (Queensland, Australia), 2017 (Idaho), and now 2024 in Quรฉbec, Canada. I paired it with the wonderful matching AP400 mount, which I had only just brought back with me the month before from Australia, where it had spent the last two decades. 

All the gear worked great. Unlike six months earlier for the October 14, 2023 annular eclipse in Utah, this time I remembered all the cables needed to have the telescope mount track the Sun.

I did mess up on a couple of settings (such as not framing the 4K movie camera as I should have โ€“ in pre-eclipse excitement I just forgot to check my chart). But none of the errors were serious. 

The eclipse in a blend of two exposures to display all the fiery pink prominences that were visible during totality around the lunar disk in one image, set against the bright inner corona of the Sun with the dark disk of the Moon in silhouette in front of the Sun.

Once started all my cameras, except for the one on the Traveler, ran unattended. 

At this eclipse I was determined to get a good look at it through the small visual scope I had piggybacked onto the Traveler photo scope. While I had used a similar rig in 2017, I only thought to look through the visual scope 20 seconds before totality ended. 

Not this year. 

A telescopic close-up of the eclipsed Sun. Onto the central blend of images for totality I layered in single images of each of the diamond rings before and after totality. They are when the last or first burst of sunlight shines through lunar valleys. The first diamond ring is at top left, the last at bottom right, so time runs from left to right.

I got a great look at the eclipsed Sun, its corona structures, flaming pink prominences, and breakout of the red chromosphere layer just as totality ended. (You canโ€™t easily see the chromosphere at the start of totality as it can be risky looking too soon through optics when the Sunโ€™s blindingly bright photosphere is still in view.) 

This is a composite showing the sequence of events surrounding totality, from just before totality (at upper left) to just after totality (at lower right), with totality in the middle. The contact images were taken 0.6 seconds apart.

And yet, as at all eclipses, I found the naked eye view the most compelling. The โ€œblack holeโ€ Sun looked huge and unearthly. While I had binoculars handy, the same 12×36 image-stabilized binoculars I bring to most eclipses, I completely forgot to look though them, just as I forget at most eclipses! 

This is a composite showing the complete sequence of the April 8, 2024 eclipse of the Sun, from first contact (at upper left) to last contact (at lower right), with totality at mid-eclipse in the middle.

I shot all the images with the Astro-Physics Traveler 105mm refractor at 630mm focal length and f/6, with the Canon R5 at ISO 100. The partial phases are 1/800 or 1/400 second exposures through a Kendrick/Baader solar filter.

Wanting to record the full sequence, I shot the partial phases until the bitter end. But post-eclipse, people came over and had a look through my scope (I think mine was the only telescope on site). We had a great time exchanging impressions. The hand-held phone camera photos people showed me looked fabulous! 

I looked for fleeting shadow bands just before and after totality (I laid out a white sheet on the ground for the purpose) but saw none, a negative observation confirmed by a fellow eclipse chaser at the site. 

Time-lapse movies of the second and third contact (start and end of totality) diamond rings, shot through the telescope with the Canon R5 in continuous burst mode for hundreds of frames each.

I did two live interviews for CBC Radio, for the Edmonton and Calgary stations, but not until after the eclipse ended. By the time I did those and finished packing away my carload of gear, it was 6:30 p.m., three hours after totality. 

I was the last to leave the site, with fishermen now arriving for an eveningโ€™s catch.

I was in that shadow as the Space Station flew over. Astronauts saw the elliptical shadow moving over eastern Canada.
The passage of the lunar shadow across the continent, showing where the clouds were. I was under the wispy clouds at upper right in Quรฉbec.

I faced no traffic jams heading back to the hotel at Ste. Helen-de-Bagot. I processed and posted one eclipse image that night. And I revised the price (down to $2.99 U.S.) and description of my How to Photograph the Solar Eclipses ebook, as now only the big processing chapter is of any value, post-eclipse. It continues to sell. 

This is the waxing crescent Moon on April 10, 2024, two days after it eclipsed the Sun, and with it above the bright planet Jupiter, with it also near Uranus. Below the solar system worlds is the faint Comet 12P/Pons-Brooks, visible here as a fuzzy star with a stubby tail..

On the long drive back to Alberta, with the pressure of having to make time now gone, I spent pleasant evenings stopping to see friends and family on the road home. So I didnโ€™t start work on the complex blends and composite images I show here until I got home a week after the eclipse. 

The happy eclipse chaser having bagged his game!

The 17-day-long drive was nearly 9,000 km over 100 hours behind the wheel. Was it worth it? Of course! 

Would I do it again? Itโ€™s a moot question as none of the upcoming eclipses allows for a cross-continent drive. Except perhaps in July 2028 in Australia. But I suspect just heading inland a day or two over the Great Dividing Range will be enough to get away from winter coastal cloud in New South Wales. (Sydney is in the path, but so is a cottage I rented last month near Coonabarabran for my superb March stay under the southern skies!)

The next total eclipse of the Sun visible from anywhere in Canada will be August 22, 2044. I wonโ€™t have to drive anywhere, as it passes right over my house! But I will have to live that long to enjoy a eclipse from my own backyard. 

I suspect this was my last chance to see โ€“ and drive to โ€“ a total eclipse in Canada.

โ€” Alan, ยฉ 2024 amazingsky.com 

Tutorials and Tips for the Solar Eclipse


As eclipse day approaches here are some tips and video tutorials from me about how best to capture the total eclipse of April 8, 2024.

There are many ways to capture great images and movies of a total eclipse of the Sun. I outline them all in great detail in my 380-page ebook How to Capture the Solar Eclipses, linked to at right.

Originally published in June 2023, I revised the ebook following the October 14, 2023 annular eclipse of the Sun to include “lessons learned at the eclipse,” and some processing tutorials on assembling annular eclipse composites. I’ve also added new content on using software to control cameras and updated information about solar filters.

Brief Tips and Techniques

The August 21, 2017 total solar eclipse over the Grand Tetons as seen from the Teton Valley in Idaho, near Driggs. With the Canon 6D and 14mm SP Rokinon lens at f/2.5 for 1/10 second at ISO 100.

My breakdown of recommend methods, in order from simplest to most complex, and with increasing demands on your time, is generally this:

  1. Use a Phone Camera for a Movie. While they can be used for a quick handheld grab shot during totality, a better method is to place a phone on a tripod using a clamp of some kind. Then a few minutes before totality aim and frame the scene, with no filter over the camera lens. Start it in movie mode to record video of the eclipse and sky changes, and the excited sounds of your group! Just remember to stop the video shortly after the end of totality and aim the phone away from the Sun. Never leave any unfiltered camera aimed at the Sun for a long time.
  2. Shoot a Wide-Angle Time-Lapse. Using a DSLR or mirrorless camera and a wide-angle lens (it might need to be as wide as a 14mm at sites in Mexico and the southern U.S.) aim and frame the camera to include the Sun and landscape below. Focus the lens! And leave it on manual focus. But put the camera into Auto-Exposure Aperture Priority (Av) with wide-area metering and with it set to underexpose by -1 EV Exposure Compensation. With the camera at ISO 100 or 200, use either its internal intervalometer (if it has one) or an external intervalometer to take frames once per second. Start the sequence with no filter on the lens a few minutes before totality. Let it run on its own until a few minutes after totality. The result is hundreds of frames you can turn into a time-lapse movie of the lunar shadow approaching and receding, and of the changes in sky colours. Or you can extract single frames at key points to process individually, as I did for the image above from August 2017. The advantage, as with the phone camera movie method, is that the camera, once going, requires no further attention. You can enjoy the eclipse!
  3. Shoot a Telephoto Video. Use a 300mm to 500mm lens on a DSLR or mirrorless camera to shoot a real-time close-up video of the eclipse. Start the video a minute or two before totality with the Sun positioned to the left of frame centre and with a solar filter over the lens. Use a slow ISO, the lens wide open (typically f/4 to f/5.6) and the camera on Auto-Exposure Aperture Priority (Av). Just be careful to focus precisely on the filtered Sun before starting the video. Poor focus is what spoils most eclipse images, not poor exposure. Just before totality (about 30 seconds prior to Second Contact) remove the filter. The auto-exposure will compensate and provide a proper exposure for the rest of totality. Just let the camera run and the Sun drift across the frame from left to right. Just remember to replace the filter, or cap the lens, and stop the video shortly (~30 seconds) after totality and Third Contact. The video will capture the diamond rings and a well-exposed corona. Vary the exposure compensation during totality if you wish, but that involves more work at the camera. Otherwise, you can just let the camera run. But, as I illustrate in my ebook, it’s important to plan and place the Sun correctly to begin with (using a planetarium app to plan the sequence), so it does not drift off the frame or close to the edge.
  4. Shoot Telephoto Close-Up Stills. Use the same type of gear to shoot still images. While you could shoot stills on Auto-Exposure, it’s better to shoot still images over a range of exposures, from very short (~1/1000 second) for the diamond rings and prominences, to long (~1 second) for the outer corona. No one exposure can capture all that the eye can see during totality. This takes more work at the camera, and with the camera on a static tripod you might have to re-centre the Sun during totality, another thing to fuss with and where things can go wrong. Using the camera’s Auto-Bracketing mode can help automate the shooting, allowing the camera to automatically shoot a set of 7 to 9 exposures at say, one-stop increments in quick succession with just one press of the shutter button (by using the self-timer set to 2 seconds).
  5. Shoot with a Telescope on a Tracking Mount. Telescopes (I like 60mm- to 100mm-aperture apochromatic refractors) allow longer focal lengths, though I would advise against shooting with any optics longer than 600mm to 800mm, so the image frames the corona well. Use similar settings as above, but with the telescope (or a telephoto lens) on a tracking mount to turn from east to west at the same rate as the sky moves. That will ensure the Sun stays centred on its own, provided you have at least roughly polar aligned the mount. (Set it to your site’s latitude and aim the polar axis as due north as you can determine from compass apps.)

Those are brief summaries of the methods I recommend, as they are ones I’ve used with success in the past and plan to use on April 8. My ebook contains much more information, and answers to most of the “But what about using ….?” questions. And I provide lots of information on what can go wrong! Some learned the hard way over 16 previous total solar eclipses.

Video Tutorials

For a video tutorial, check out the webinar I conducted as part of the Kalamazoo Astronomical Society’s excellent Eclipse Series here on YouTube. It is about a 1-hour presentation, plus with lots of Q&A at the end.

KAS Eclipse Series โ€” Part 1: Shooting

Of course, once you have all your images, you need to process them. My ebook’s biggest chapter (at 80 pages) is the one on processing still images and time-lapses.

So, a month after I presented the above webinar on Shooting, I was back on-line again for a follow-up webinar on Processing. You can view that KAS Eclipse Series tutorial here on YouTube.

KAS Eclipse Series โ€” Part 2: Processing

I cover processing single wide-angle images, a wide-angle time-lapse series, single-image close-ups, and blending multiple exposure composites.

A month later, I presented a further webinar to the Astronomical League as part of their AL Live series, again on shooting the eclipse, but now with an emphasis on techniques amateur astronomers and astrophotographers with typical telescope gear might use.

You can view the AL Live webinar here. My presentation begins at the 44-minute mark.

AL Live Webinar โ€” Scrub ahead to 44 minutes

I emphasized that the kinds of gear astrophotographers use these days with great success on deep-sky objects might not work well for the eclipse. The specialized cameras, and software used to control them, are just not designed for the demands of a total eclipse, where exposures have to range over a wide array of settings and change very quickly. Images have to be taken and recorded in rapid succession.

I suspect a lot of ambitious and overly-confident astrophotographers will come away from the 2024 eclipse disappointed โ€” and what’s worse, without having seen the eclipse because they were too wrapped up looking at laptop screens trying to get their high-tech gear working.

The Checklist page from my eBook

Practice, Practice, Practice

In these webinars and in my ebook, my common theme is the importance of practicing.

Don’t assume something will work. Practice with the gear you intend to use, on the Sun now (with proper filters) and on the Moon. The crescent Moon, with dim Earthshine lighting the lunar night side, is a great practice target because of its wide range of brightness. And it moves like the Sun will, to check maximum exposure times vs. image blurring from motion.

Practice with your tripod or mount aimed to the altitude and location in the sky where the Sun will be from the site you have chosen. Set a tracking mount to the latitude you will be at to be sure it will aim at and track the Sun without issues. Some telescope mounts stop tracking when they reach due south, exactly where the Sun will be at totality from southern sites. That’s a nasty surprise you do not want to encounter on eclipse day.

All this and much more is covered in my ebook, available for Apple Books and as a PDF for all platforms here from my website at https://www.amazingsky.com/EclipseBook

Good luck on eclipse day!

โ€” Alan, February 21, 2024

The Best Sky Sights of 2023


May 10, 1994 Annular Eclipse taken from a site east of Douglas, Arizona showing “reverse” Bailey’s Beads โ€”lunar mountains just touching Sun’s limb 4-inch f/6 apo refractor at f/15 with Barlow lens Ektachrome 100 slide film.

Hereโ€™s my preview of some of the best celestial events for 2023. Mine is certainly not an exhaustive list. Iโ€™ve picked just one event per month, and Iโ€™ve focused on events best for unaided eyes or binoculars, and visible from North America. (So the solar eclipse of April 20 visible from Australia and the South Pacific, and the two minor lunar eclipses this year donโ€™t make the cut!)

For most events, unless otherwise stated, the scene depicted is for southern Ontario, Canada. However, the view will be similar from other locations. All sky charts were created with SkySafari software, available here for desktop and mobile devices.

Click or tap on any of the illustrations to bring up a full-screen view with more detail and readable labels!


JANUARY 

As 2023 opens, Venus is beginning its climb into the evening sky, while Saturn is sinking into the sunset. The two planets pass each other on Sunday, January 22, when they appear just one-third of a degree apart in the twilight. Use binoculars to pick out dimmer Saturn. And look for the thin day-old crescent Moon just over a binocular field below the planet pair. 


FEBRUARY

A month later, on Wednesday, February 22, Venus has now ascended higher, preparing to meet up with descending Jupiter. But before they meet, the crescent Moon, with its dark side lit by faint Earthshine, joins the planets in a particularly close conjunction with Jupiter. They will appear about 1ยฐ (two Moon diameters) apart, with Venus about a binocular field below. 


MARCH

Hereโ€™s a date to circle on your calendar. On Wednesday, March 1 the skyโ€™s two brightest planets, Venus and Jupiter, pass within half a degree of each other, in arguably the yearโ€™s best conjunction. Theyโ€™ll be close enough to frame nicely at medium power in a telescope, though the featureless gibbous disk of Venus will appear small, about the third the size of Jupiterโ€™s banded globe. But Venus is by far the brighter of the two worlds. 


APRIL

If you want to check Mercury off your sighting list this year, this is a good week to do it. On April 11 Mercury reaches its greatest angle away from the Sun in the evening sky, and for northern hemisphere viewers, is angled at its highest in the western sky. Even so, look just a binocular field above the horizon. While youโ€™re at it, look higher for the fine sight of Venus near the Pleiades star cluster. 


MAY

Wednesday, May 17 brings a chance to see the crescent Moon pass in front of Jupiter. But it will be a tricky event to catch. While most of North America and parts of Northern Europe can see the occultation, it occurs in the daytime sky with the Moon only 25ยฐ west of the Sun. However, locations along the West Coast of North America can see either the start or end of the occultation in a bright pre-dawn sky. Vancouver, Canada sees Jupiter disappear before sunrise, while Los Angeles โ€“ the view shown above โ€“ sees Jupiter reappear just before sunrise. Other locations will see a close conjunction of the Moon and Jupiter low in the dawn sky.


JUNE

As June opens we have Venus still shining brightly in the evening below much dimmer Mars, now far from the Earth and tiny in a telescope. But itโ€™ll be worth a look this night even in binoculars as the red planet passes in front of the Beehive star cluster, also known as Messier 44. If you miss June 2, Mars will be close to the Beehive the night before and after. 


JULY

Venus has been bright all spring, but on July 7 it officially peaks at its maximum brilliance, reaching a blazing magnitude of -4.7. It reached its greatest angle from the Sun a month earlier on June 4 and is now dropping closer to the Sun each evening. But you still canโ€™t miss it. What you might miss is dim Mars above, now close to the star Regulus in Leo. Mars passes 3/4 of a degree above Regulus on July 9 and 10. Youโ€™ll need binoculars to pick out the pairing. 


AUGUST

Everyone looks forward to the annual summer stargazing highlight โ€“ watching the Perseid meteor shower. This is a good year, with the peak hour of the shower falling in the middle of the night of August 12/13 for North America. Thatโ€™s a Saturday night! But most importantly, the waning Moon doesnโ€™t rise until the wee hours, as shown here, so its light wonโ€™t wash out the meteors. Plan to be at a dark site for an all-night meteor watch. 


SEPTEMBER

By September Venus has made the transition into the morning sky and shines at its greatest dawn-sky brilliance on September 19. It will then be joined by Mercury, with the inner planet reaching its greatest angle away from the Sun on September 22 shown here. This is the best morning appearance of Mercury for Northern Hemisphere observers. The view this morning bookends the view five months earlier on April 11. If you are away from urban light pollution, also look for the faint glow of Zodiacal Light in the pre-dawn sky before Mercury rises. 


OCTOBER

October is solar eclipse month! On Saturday, October 14 the shadow of the Moon passes across all of North America and most of South America. Everyone on those two continents sees a partial eclipse of the Sun. But those along a narrow path sweeping across the western U.S. and down into Mexico, Central America and across northern South America can see a rare โ€œring of fireโ€ eclipse as the Moonโ€™s dark disk eclipses the Sun, but isnโ€™t quite large enough to totally cover it. This is an โ€œannularโ€ eclipse. The view above is from Albuquerque, New Mexico, one of the largest U.S. cities in the path of annularity, second only to San Antonio, Texas. 

This is the path of annularity across the western U.S. To see the Moon pass centrally across the Sun (the “ring of fire”) you have to be somewhere in that grey path. Outside the path you will see only a partial eclipse of the Sun. For detailed and zoomable eclipse path maps like the one above, please visit EclipseWise.com.


NOVEMBER

Close conjunctions between the crescent Moon and Venus are always notable. Get up early on Thursday, November 9 to see the 26-day-old Moon shining only a degree below Venus. Venus reached its greatest angle away from the Sun on October 23. It is now descending back toward the Sun, but remains high in the morning sky in early November.


DECEMBER 

Though it usually puts on a better show than the summer Perseids, the Geminid meteor shower is not as popular because itโ€™s cold! But this is also a good year for the Geminids as it peaks only two days after New Moon. The best night might be Thursday, December 14, but a good number of meteors should be zipping across the sky the night before on December 13, shown here. Start watching at nightfall and go as long as you can in the chill of a December night. 

To download my free Amazing Sky 2023 Calendar in PDF format, go to my website at https://www.amazingsky.com/Books The PDF file can be printed out at home or taken to an office supply shop to be printed and bound.

Good luck in your stargazing and clear skies for 2023!

โ€” Alan, January 15, 2023 / AmazingSky.com

Testing Noise Reduction Programs for Astrophotography


In a detailed technical blog I compare six AI-based noise reduction programs for the demands of astrophotography. Some can work wonders. Others can ruin your image. 

Over the last two years we have seen a spate of specialized programs introduced for removing digital noise from photos. The new generation of programs use artificial intelligence (AI), aka machine learning, trained on thousands of images to better distinguish unwanted noise from desirable image content.

At least thatโ€™s the promise โ€“ and for noisy but normal daytime images they do work very well. 

But in astrophotography our main subjects โ€“ stars โ€“ can look a lot like specks of pixel-level noise. How well can each program reduce noise without eliminating stars or wanted details, or introducing odd artifacts, making images worse. 

To find out, I tested six of the new AI-based programs on real-world โ€“ or rather โ€œreal-skyโ€ โ€“ astrophotos. Does one program stand out from the rest for astrophotography? 

NOTE: All the images are full-resolution JPGs you can tap or click on to download for detailed inspection. But that does make the blog page slow to load initially. Patience! 


TL;DR SUMMARY

The new AI-trained noise reduction programs can indeed eliminate noise better than older non-AI programs, while leaving fine details untouched or even sharpening them. 

  • Of the group tested, the winner for use on just star-filled images is a specialized program for astrophotography, NoiseXTerminator from RC-Astro.
  • For nightscapes and other images, Topaz DeNoise AI performed well, better than it did in earlier versions that left lots of patchy artifacts, something AI programs can be prone to. 
  • While ON1โ€™s new NoNoise AI 2023 performed fine, it proved slightly worse in some cases than its earlier 2022 version. Its new sharpening routine needs work.
  • Other new programs, notably Topaz Photo AI and Luminarโ€™s Noiseless AI, also need improvement before they are ready to be used for the rigours of astrophotography. 
  • For reasons explained below, I would not recommend DxOโ€™s PureRAW2.ย [See below for comments on the newer DxO PureRaw3, which suffers from the same issues.]

The three test images in Adobe Camera Raw showing the Basic settings applied.

METHODOLOGY

As described below, while some of the programs can be used as stand-alone applications, I tested them all as plug-ins for Photoshop, applying each as a smart filter applied to a developed raw file brought into Photoshop as a Camera Raw smart object. 

Most of these programs state that better results might be obtainable by using the stand-alone app on original raw files. But for my personal workflow I prefer to develop the raw files with Adobe Camera Raw, then open those into Photoshop for stacking and layering, applying any further noise reduction or sharpening as non-destructive smart filters. 

Many astrophotographers also choose to stack unedited original images with specialized stacking software, then apply further noise reduction and editing later in the workflow. So my workflow and test procedures reflect that. 

However, the exception is DxOโ€™s PureRAW2. It can work only on raw files as a stand-alone app, or as a plug-in from Adobe Lightroom. It does not work as a Photoshop plug-in. I tested PureRAW2 by dropping raw Canon .CR3 files onto the app, then exporting the results as raw DNG files, but with the same settings applied as with the other raw files. For the nightscape and wide-field images taken with lenses in DxO’s extensive database, I used PureRAW’s lens corrections, not Adobe’s.

As shown above, I chose three representative images: 

  • A nightscape with star trails and a detailed foreground, at ISO 1600.
  • A wide-field deep-sky image at ISO 1600 with an 85mm lens, with very tiny stars.
  • A close-up deep-sky image taken with a telescope and at a high ISO of 3200, showing thermal noise hot pixels. 

Each is a single image, not a stack of multiple images. 

Before applying the noise reduction, the raw files received just basic color corrections and a contrast boost to emphasize noise all the more. 


THE CONTENDERS

In the test results for the three images, I show the original raw image, plus a version with noise reduction and sharpening applied using Adobe Camera Rawโ€™s own sliders, with luminance noise at 40, color noise at 25, and sharpening at 25. 

I use this as a base comparison, as it has been the noise reduction I have long applied to images. However, ACRโ€™s routine (also found in Adobe Lightroom) has not changed in years. It is good, but it is not AI.

[See below for an April 2023 update with a comparison of Adobe’s new AI Denoise with DxO DeepPrimeXD and Topaz PhotoAI.]

The new smart AI programs should improve upon this. But do they?

PLEASE NOTE: 

  • I have refrained from providing prices and explaining buying options, as frankly some can be complex! 
  • For those details and for trial copies, go to the softwareโ€™s website by clicking on the link in the header product names below. 
  • All programs are available for Windows and MacOS. I tested the latter versions. 
  • I have not provided tutorials on how to use the software; I have just reported on their results. For trouble-shooting their use, please consult the software company in question. 
ON1 NoNoise 2023’s control interface.

ON1 NoNoise AI 2023

ON1โ€™s main product is the Lightroom/Photoshop alternative program called ON1 Photo RAW, which is updated annually to major new versions. It has full cataloging options like Lightroom and image layering like Photoshop. Its Edit module contains the NoNoise AI routine. But NoNoise AI can be purchased as a stand-alone app that also installs as a plug-in for Lightroom and Photoshop. Itโ€™s what I tested here. The latest 2023 version of NoNoise AI added ON1โ€™s new Tack Sharp AI sharpening routine.

Version tested: 17.0.1

Topaz DeNoise AI’s four-pane view to select the best AI model.

Topaz DeNoise AI 

This program has proven very popular and has been adopted by many photographers โ€“ and astrophotographers โ€“ as an essential part of an editing workflow. It performs noise reduction only, offering a choice of five AI models. Auto modes can choose the models and settings for you based on the image content, but you can override those by adjusting the strength, sharpness, and recovery of original detail as desired.

A separate program, Topaz Sharpen AI, is specifically for image sharpening, but I did not test it here. Topaz Gigapixel AI is for image resizing.

Version tested: 3.7.0

Topaz Photo AI’s control interface for its three main functions: noise, sharpening and upscaling.

Topaz Photo AI

In 2022 Topaz introduced this new program which incorporates the trio of noise reduction, sharpening and image resizing in one package. Like DeNoise, Sharpen and Gigapixel, Photo AI works as a stand-alone app or as a plug-in for Lightroom and Photoshop. Photo AIโ€™s Autopilot automatically detects and applies what it thinks the image needs. While it is possible to adjust settings, Photo AI offers much less control than DeNoise AI and Topazโ€™s other single-purpose programs. 

As of this writing in November 2022 Photo AI is enjoying almost weekly updates, and seems to be where Topaz is focusing its development and marketing effort.ย [See below for a test of PhotoAI v1.3.1, current as of April 2023.]

Version tested: 1.0.9

Luminar Neo’s Edit interface with choices of many filters and effects, including Noiseless AI.

Luminar Neo Noiseless AI

Unlike the other noise reduction programs tested here, Luminar Neo from the software company Skylum is a full-featured image editing program, with an emphasis on one-click AI effects. One of those is the new Noiseless AI, available as an extra-cost extension to the main Neo program, either as a one-time purchase or by annual subscription. Noiseless AI cannot be purchased on its own. However, Neo with most of its extensions does work as a plug-in for Lightroom and Photoshop. 

Being new, Luminar Neo is also updated frequently, with more extensions coming in the next few months. 

Version tested: 1.5.0

DxO PureRAW’s simple interface with few choices for Noise Reduction settings.

DxO PureRAW2

Like ON1, DxO makes a full-featured alternative to Adobeโ€™s Lightroom for cataloging and raw developing called DxO PhotoLab, in version 6 as of late 2022. It contains DxOโ€™s Prime and DeepPrime noise reduction routines. However, as with ON1, DxO has spun off just the noise reduction and lens correction parts of PhotoLab into a separate program, PureRAW2, which runs either as a stand-alone app or as a plug-in for Lightroom โ€“ but not Photoshop, as PureRAW works only on original raw files. 

Unlike all the other programs, PureRAW2 offers essentially no options to adjust settings, just the option to apply, or not, lens corrections, and to choose the output format. For this testing I applied DeepPrime and exported out to DNG files.ย [See below for a test of DeepPrimeXD, now offered with PureRaw3.]

Version tested: 2.2

Noise Terminator’s controls allow adjusting strength and detail.

RC-Astro NoiseXTerminator

Unlike the other programs tested, NoiseXTerminator from astrophotographer Russell Croman is designed specifically for deep-sky astrophotography. It installs as a plug-in for Photoshop or Affinity Photo, but not Lightroom. It is also available under the same purchased licence as a โ€œprocessโ€ for PixInsight, an advanced program popular with astrophotographers, as it is designed just for editing deep-sky images. 

I tested the Photoshop plug-in version of Noise XTerminator. It receives occasional updates to both the actual plug-in and separate updates to the AI module.  

Version tested: 1.1.2, AI model 2 


NIGHTSCAPE TEST

As with the other test images, the panels show a highly magnified section of the image, indicated in the inset. I shot the image of Lake Louise in Banff, Alberta with a Canon RF15-35mm lens on a 45-megapixel Canon R5 camera at ISO 1600. 

The test results on a sample nightscape.
  • Adobe Camera Rawโ€™s basic noise reduction did a good job, but like all general routines it does soften the image as a by-product of smoothing out high-ISO noise.
  • ON1 NoNoise 2023 retained landscape detail better than ACR but softened the star trails, despite me adding sharpening. It also produced a somewhat patchy noise smoothing in the sky. This was with Luminosity backed off to 75 from the auto setting (which always cranks up the level to 100 regardless of the image), and with the Tack Sharp routine set to 40 with Micro Contrast at 0. It left a uniform pixel-level mosaic effect in the shadow areas. Despite the new Tack Sharp option, the image was softer than with last yearโ€™s NoNoise 2022 version (not shown here as it is no longer available) which produced better shadow results.
  • Topaz DeNoise AI did a better job than NoNoise retaining the sharp ground detail while smoothing noise, always more obvious in the sky in such images. Even so, it also produced some patchiness, with some areas showing more noise than others. This was with the Standard model set to 40 for Noise and Sharpness, and Recover Details at 75. I show the other model variations below. 
  • Topaz Photo AI did a poor job, producing lots of noisy artifacts in the sky and an over-sharpened foreground riddled with colorful speckling. It added noise. This was with the Normal setting and the default Autopilot settings.
  • Noiseless AI in Luminar Neo did a decent job smoothing noise while retaining, indeed sharpening ground detail without introducing ringing or colorful edge artifacts. The sky was left with some patchiness and uneven noise smoothing. This was with the suggested Middle setting (vs Low and High) and default levels for Noise, Detail and Sharpness. However, I do like Neo (and Skylum’s earlier Luminar AI) for adding other finishing effects to images such as Orton glows.
  • DxO PureRAW2 did smooth noise very well while enhancing sharpness quite a lot, almost too much, though it did not introduce obvious edge artifacts. Keep in mind it offers no chance to adjust settings, other than the mode โ€“ I used DeepPrime vs the normal Prime. Its main drawback is that in making the conversion back to a raw DNG image it altered the appearance of the image, in this case darkening the image slightly. It also made some faint star trails look wiggly!  
  • Noise XTerminator really smoothed out the sky, and did so very uniformly without doing much harm to the star trails. However, it smoothed out ground detail unacceptably, not surprising given its specialized training on stars, not terrestrial content. 

Conclusion: For this image, Iโ€™d say Topaz DeNoise AI did the best, though not perfect, job. 

This was surprising, as tests I did with earlier versions of DeNoise AI showed it leaving many patchy artifacts and colored edges in places. Frankly, I was put off using it. However, Topaz has improved DeNoise AI a lot. 

Why it works so well, when Topazโ€™s newer program Photo AI works so poorly is hard to understand. Surely they use the same AI code? Apparently not. Photo AIโ€™s noise reduction is not the same as DeNoise AI. 

Similarly, ON1โ€™s NoNoise 2023 did a worse job than their older 2022 version. One can assume its performance will improve with updates. The issue seems to be with the new Tack Sharp addition.

NoiseXTerminator might be a good choice for reducing noise in just the sky of nightscape images. It is not suitable for foregrounds, though as of April 2023 its performance on landscapes has improved but is not ideal.ย 


WIDE-FIELD IMAGE TEST

I shot this image of Andromeda and Triangulum with an 85mm Rokinon RF lens on the 45-megapixel Canon R5 on a star tracker. Stars are now points, with small ones easily mistaken for noise. Letโ€™s see how the programs handle such an image, zooming into a tiny section showing the galaxy Messier 33. 

The test results on a sample wide-field deep-sky image.
  • Adobe Camera Rawโ€™s noise and sharpening routines do take care of the worst of the luminance and chrominance noise, but inevitably leave some graininess to the image. This is traditionally dealt with by stacking multiple sub-exposures. 
  • ON1 NoNoise 2023 did a better job than ACR, smoothing the worst of the noise and uniformly, without leaving uneven patchiness. However, it did soften star images, almost like it was applying a 1- or 2-pixel gaussian blur, adding a slight hazy look to the image. And yet the faintest stars that appeared as just perceptible blurs in the original image were sharpened to one- or two-pixel points. This was with only NoNoise AI applied, and no Tack Sharp AI. And, as I show below, NoNoise’s default “High Detail” option introduced with the 2022 version and included in the 2023 edition absolutely destroys star fields. Avoid it.
ON1 NoNoise “High Detail” option ruins star fields, as shown at right. Use “Original” instead.
  • Topaz DeNoise AI did a better job than Camera Raw, though it wasnโ€™t miles ahead. This was with the Standard setting. Its Low Light and Severe models were not as good, surprising as you might think one of those choices would be the best for such an image. It pays to inspect Topazโ€™s various modelsโ€™ results. Standard didnโ€™t erase stars; it actually sharpened the fainter ones, almost a little too much, making them look like specks of noise. Playing with Enhance Sharpness and Recover Detail didnโ€™t make much difference to this behavior. 
  • Topaz Photo AI again performed poorly. Its Normal mode left lots of noise and grainy artifacts. While its Strong mode shown here did smooth background noise better, it softened stars, wiping out the faint ones and leaving colored edges on the brighter ones. 
  • Noiseless AI in Luminar Neo did smooth fine noise somewhat, better than Camera Raw, but still left a grainy background, though with the stars mostly untouched in size and color. 
  • DxO PureRAW2 did eliminate noise quite well, while leaving even the faintest stars intact, unlike with the deep-sky image below, which is odd. However, it added some dark halos to bright stars from over-sharpening. And, as with the nightscape example, PureRAWโ€™s output DNG was darker than the raw that went in. I donโ€™t want noise reduction programs altering the basic appearance of an image, even if that can be corrected later in the workflow. 
  • Noise XTerminator performed superbly, as expected โ€“ after all, this is the subject matter it is trained to work on. It smoothed out random noise better than any of the other programs, while leaving even the faintest stars untouched, in fact sharpening them slightly. Details in the little galaxy were also unharmed. 

Conclusion: The clear winner was NoiseXTerminator. 

Topaz DeNoise was a respectable second place, performing better than it had done on such images in earlier versions. Even so, it did alter the appearance of faint stars which might not be desirable. 

ON1 NoNoise 2023 also performed quite well, with its softening of brighter stars yet sharpening of fainter ones perhaps acceptable, even desirable for an effect. 


TELESCOPIC DEEP-SKY TEST

I shot this image of the NGC 7822 complex of nebulosity with a SharpStar 61mm refractor, using the red-sensitive 30-megapixel Canon Ra and with a narrowband filter to isolate the red and green light of the nebulas. 

Again, the test image is a single raw image developed only to re-balance the color and boost the contrast. No dark frames were applied, so the 8-minute exposure at ISO 3200 taken on a warm night shows thermal noise as single โ€œhot pixelโ€ white specks. 

The test results on a sample deep-sky close-up.
  • Adobe Camera Raw did a good job smoothing the worst of the noise, suppressing the hot pixels but only by virtue of it softening all of the image slightly at the pixel level. However, it leaves most stars intact. 
  • ON1 NoNoise 2023 also did a good job smoothing noise while also seeming to boost contrast and structure slightly. But as in the wide-field image, it did smooth out star images a little, though somewhat photogenically, while still emphasizing the faintest stars. This was with no sharpening applied and Luminosity at 60, down from the default 100 NoNoise applies without fail. One wonders if it really is analyzing images to produce optimum settings. With no Tack Sharp sharpening applied, the results on this image with NoNoise 2023 looked identical to NoNoise 2022. 
  • Topaz DeNoise AI did another good job smoothing noise, while leaving most stars unaffected. However, the faintest stars and hot pixels were sharpened to be more visible tiny specks, perhaps too much, even with Sharpening at its lowest level of 1 in Standard mode. Low Light and Severe modes produced worse results, with lots of mottling and unevenness in the background. Unlike NoNoise, at least its Auto settings do vary from image to image, giving you some assurance it really is responding to the image content. 
  • Topaz Photo AI again produced unusable results. Its Normal modes produced lots of mottled texture and haloed stars. Its Strong mode shown here did smooth noise better, but still left lots of uneven artifacts, like DeNoise AI did in its early days. It certainly seems like Photo AI is using old hand-me-down code from DeNoise AI.
  • Noiseless AI in Luminar Neo did smooth noise but unevenly, leaving lots of textured patches. Stars had grainy halos and the program increased contrast and saturation, adjustments usually best left for specific adjustment layers dedicated to the task. 
  • DxO PureRAW2 did smooth noise very well, including wiping out the faintest specks from hot pixels, but it also wiped out the faintest stars, I think unacceptably and more than other programs like DeNoise AI. For this image it did leave basic brightness alone, likely because it could not apply lens corrections to an image taken with unknown optics. However, it added an odd pixel-level mosaic-like effect on the sky background, again unacceptable.
  • Noise XTerminator did a great job smoothing random noise without affecting any stars or the nebulosity. The Detail level of 20 I used actually emphasized the faintest stars, but also the hot pixel specks. NoiseXTerminator canโ€™t be counted on to eliminate thermal noise; that demands the application of dark frames and/or using dithering routines to shift each sub-frame image by a few pixels when autoguiding the telescope mount. Even so, Noise XTerminator is so good users might not need to take and stack as many images. 

Conclusion: Again, the winner was NoiseXTerminator. 

Deep-sky photographers have praised โ€œNoiseXโ€ for its effectiveness, either when applied early on in a PixInsight workflow or, as I do in Photoshop, as a smart filter to the base stacked image underlying other adjustment layers.

Topaz DeNoise is also a good choice as it can work well on many other types of images. But again, play with its various models and settings. Pixel peep!

ON1 NoNoise 2023 did put in a respectable performance here, and it will no doubt improve โ€“ it had been out less than a month when I ran these tests. 

Based on its odd behavior and results in all three test images I would not recommend DxOโ€™s PureRAW2. Yes, it reduces noise quite well, but it can alter tone and color in the process, and add strange pixel-level mosaic artifacts.  


COMPARING DxO and TOPAZ OPTIONS 

DxO and Topaz DeNoise AI offer the most choices of AI models and strength of noise reduction. Here I compare:

  • Topaz DeNoise AI on the nightscape image using three of its models: Standard (which I used in the comparisons above), plus Low Light and Severe. These show how the other models didnโ€™t do as good a job.
  • The set below also compares DeNoise AI to Topazโ€™s other program, Photo AI, to show how poor a job it is doing in its early form. Its Strong mode does smooth noise but over-sharpens and leaves edge artifacts. Yes, Photo AI is one-click easy to use, but produces bad results โ€“ at least on astrophotos. 
Comparing DeNoise’s and Photo AI’s different model settings.

As of this writing DxOโ€™s PureRAW2 offers the Prime and newer DeepPrime AI models โ€“ I used DeepPrime for my tests. 

However, DxOโ€™s more expensive and complete image processing program, PhotoLab 6, also offers the even newer DeepPrimeXD model, which promises to preserve or recover even more โ€œXtra Detailโ€ over the DeepPrime model. As of this writing, the XD mode is not offered in PureRAW2. Perhaps that will wait for PureRAW3, no doubt a paid upgrade. 

[UPDATE MARCH 2023: DxO has indeed brought out PureRaw3 as a paid upgrade that, as expected, offers the DeepPrimeXD. In testing the new version I found that, while it did not seem to alter an image’s exposure as PureRaw2 did, DeepPrime and DeepPrimeXD still unacceptably ruin starry skies, by either adding a fine-scale mosaic effect (DeepPrime) or weird wormy artifacts (DeepPrimeXD). Try it for yourself to see if you find the same.]

Comparing DxO’s various Prime model settings. DeepPrimeXD is only in PhotoLab 6.
  • The set above compares the three noise reduction models of DxOโ€™s PhotoLab 6. DeepPrime does do a better job than Prime. DeepPrimeXD does indeed sharpen detail more, but in this example it is too sharp, showing artifacts, especially in the sky where it is adding structures and textures that are not real. 
  • However, when used from within PhotoLab 6, the DeepPrime noise reduction becomes more usable. PhotoLab is then being used to perform all the raw image processing, so PureRAWโ€™s alteration of color and tone is not a concern. Conversely, it can also output raw DNGs with only noise reduction and lens corrections applied, essentially performing the same tasks as PureRAW. If you have PhotoLab, you don’t need PureRAW.

APRIL 2023 UPDATE โ€” TESTING ADOBE’S NEW AI Denoise

In April 2023 Adobe updated Lightroom Classic to v12.3 and the Camera Raw plug-in for Bridge and Photoshop to 15.3. The major new feature was a long-awaited AI noise reduction from Adobe called Denoise. It works only on raw files and generates a new raw DNG file to which all the raw develop settings, including AI masks, can be applied. But the DNG file is some four times larger than the original raw file from the camera.

Here’s a comparison of Camera Raw using the old noise reduction and the new AI option, with DxO’s DeepPrimeXD and Topaz’s PhotoAI, on an aurora image from April 23, 2023:

I used Topaz Photo AI as that’s the program Topaz is now putting all their development effort into, neglecting their other plug-ins such as DeNoise AI. I used DxO PhotoLab 6 with its DeepPrimeXD option to export a DNG with only noise reduction applied, for results identical to what is now offered with DxO’s separate PureRaw3 plug-in.

At 100% above, there’s very little obvious difference. They show up when pixel peeping.

400% blow-ups of the sky – Tap or click to download a full-res JPG

Above are 400% blow-ups of a section of the sky.

Compared to using Adobe’s old noise reduction sliders, their new AI Denoise did a far superior job at smoothing noise, and providing sharpening โ€“ย almost too much, making even the smallest stars pop out more, perhaps a good thing. But there’s no control of that sharpening.

DxO’s DeepPrimeXD provides a similar, or perhaps more excessive level of AI sharpening. While it smooths noise, it introduces all manner of wormy AI artifacts. It is unacceptable.

Topaz PhotoAI’s noise reduction and sharpening, here both applied with their AutoPilot settings, smoothed noise, but created a patchy appearance. It also softened the stars, despite having sharpening turned on. It was the worst of the set.

400% blow-ups of a section of the ground y – Tap or click to download a full-res JPG

In a similar set of blow-ups of the ground, the old Adobe noise reduction did just that โ€” it smoothed only some noise. The new AI Denoise not only smooths noise, it also applies AI-based sharpening, to the point of almost inventing detail. Here it looks believable, but in other tests I have seen it add content, such as structures in the aurora, that looked fake and out of place. Or just plain wrong!

DxO’s DeepPrimeXD’s main feature over the older DeepPrime is the “eXtra Detail” it finds. Here it produces a result similar to Adobe Denoise, though in some areas of this and other images, I find it is over-sharpening. As with Adobe, there is no option for backing off the sharpening. Other than using DeepPrime or Prime noise reduction.

Topaz PhotoAI didn’t do much to add sharpening. If anything, it made the image softer. While PhotoAI has improved with its weekly updates, it still falls far short of the competition, at least for astrophotos and nightscapes.

The bottom line โ€” Adobe’s new AI Denoise can do a superb job on astrophotos, and will be particularly useful for high-ISO nightscapes, perhaps better than any of the competition. But watch what it does! It can invent details or create results that look artificial. Being able to adjust the sharpening would be helpful. Perhaps that will come in an update.


COMPARING AI TO OLDER NON-AI PROGRAMS

The new generation of AI-based programs have garnered all the attention, leaving older stalwart noise reduction programs looking a little forlorn and forgotten. 

Here I compare Camera Raw and two of the best of the AI programs, Topaz DeNoise AI and NoiseXTerminator, with two of the most respected of the โ€œold-schoolโ€ non-AI programs: 

Nik Dfine2’s control interface.
  • Dfine2, included with the Nik Collection of plug-ins sold by DxO (shown above), and
  • Reduce Noise v9 sold by Neat Image (shown below). 
Neat Image’s Reduce Noise control interface – the simple panel.

I tested both by using them in their automatic modes, where they analyze a section or sections of the image and adjust the noise reduction accordingly, but then apply that setting uniformly across the entire image. However, both allow manual adjustments, with Neat Imageโ€™s Reduce Noise offering a bewildering array of technical adjustments. 

How do these older programs stack up to the new AI generation? Here are comparisons using the same three test images. 

Comparing results with Neat Image and Nik Dfine2 on the nightscape test image.

In the nightscape image, Nik Dfine2 and Neat Imageโ€™s Reduce Noise did well, producing uniform noise reduction with no patchiness. But the results werenโ€™t significantly better than with Adobe Camera Rawโ€™s built-in routine. Like ACR, both non-AI programs did smooth detail in the ground, compared to DeNoise AI which sharpened the mountain details. 

Comparing results with Neat Image and Nik Dfine2 on the wide-field test image.

In the tracked wide-field image, the differences were harder to distinguish. None performed up to the standard of Noise XTerminator, with both Nik Dfine2 and Neat Image softening stars a little compared to DeNoise AI. 

Comparing results with Neat Image and Nik Dfine2 on the deep-sky test image.

In the telescopic deep-sky image, all programs did well, though none matched NoiseXTerminator. None eliminated the hot pixels. But Nik Dfine2 and Neat Image did leave wanted details alone, and did not alter or eliminate desired content. However, they also did not eliminate noise as well as did Topaz DeNoise AI or NoiseXTerminator. 

The AI technology does work! 


YOUR RESULTS MAY VARY

I should add that the nature of AI means that the results will certainly vary from image to image. 

In addition, with many of these programs offering multiple models and settings for strength and sharpening, results even from the same program can be quite different. In this testing I used either the programโ€™s auto defaults or backed off those defaults where I thought the effect was too strong and detrimental to the image.

Software is also a constantly moving target. Updates will alter how these programs perform, we hope for the better. For example, two days after I published this test, ON1 updated NoNoise AI to v17.0.2 with minor fixes and improvements.

And do remember Iโ€™m testing on astrophotos, and pixel peeping to the extreme. Rave reviews claiming how well even the poor performers here work on โ€œnormalโ€ images might well be valid. 

This is all by way of saying, your mileage may vary!

So donโ€™t take my word for it. Most programs (Luminar Neo is an exception) are available as free trial copies to test out on your astro-images and in your preferred workflow. Test for yourself. But do pixel peep. Thatโ€™s where youโ€™ll see the flaws. 


WHAT ABOUT ADOBE?

As noted above, with v15.3 of Camera Raw and v12.3 of Lightroom Classic, Adobe finally introduced their contender into the AI noise reduction contest. And it is a very good entry at that.

But it works only on raw files early in the workflow, and it generates a new raw DNG file, one four times the size of the original. The suggestion is that this technology will expand so that the AI noise reduction can be applied later in the workflow to other file formats.

Indeed, in the last couple of years Adobe has introduced several amazing and powerful โ€œNeural Filtersโ€ into Photoshop, which work wonders with one click.

Neural network Noise Reduction is coming to Photoshop. One day!

A neural filter for Noise Reduction is on Adobeโ€™s Wait List for development, so perhaps we will see something in the next few months from Adobe, as a version of the AI noise reduction now offered in Lightroom and Camera Raw.

Until then we have lots of choices for third party programs that all improve with every update. I hope this review has helped you make a choice. 

โ€” Alan, November 15, 2022 / Revised April 27, 2023 / AmazingSky.com ย 

Testing a Trio ofย Canon RF Zoom Lenses for Astrophotographyย 


In a detailed review, I test a โ€œholy trinityโ€ of premium Canon RF zoom lenses, with astrophotography the primary purpose.

In years past, zoom lenses were judged inferior to fixed-focal length โ€œprimeโ€ lenses for the demands of astrophotography. Stars are the severest test of a lens, revealing optical aberrations that would go unnoticed in normal images, or even in photos of test charts. Many older zooms just didnโ€™t cut it for discerning astrophotographers, myself included. 

The new generation of premium zooms for mirrorless cameras, from Canon, Nikon and Sony, are dispelling the old wisdom that primes are better than zooms. The new zoomsโ€™ optical performance is proving to be as good, if not better than the older generation of prime lenses for DSLR cameras, models often designed decades ago. 

The shorter lens-to-sensor โ€œflange distanceโ€ offered by mirrorless cameras, along with new types of glass, provide lens designers more freedom to correct aberrations, particularly in wide-angle lenses. 

While usually slower than top-of-the-line primes, the advantage of zoom lenses is their versatility for framing and composing subjects, great for nightscapes and constellation shots. Itโ€™s nice to have the flexibility of a zoom without sacrificing the optical quality and speed so important for astrophotography. Can we have it all? The new zooms come close to delivering.

The โ€œholy trinityโ€ of Canon zooms tested were purchased in 2021 and 2022. From L to R they are: RF15-35mm, RF28-70mm, and RF70-200mm

A good thing, because with Canon we have little choice! For top-quality glass in wide-angle focal lengths at least, zooms are the only choice for their mirrorless R cameras. As of this writing in late 2022, Canon has yet to release any premium primes for their RF mount shorter than 50mm. Rumours are a 12mm, 24mm, 28mm, and 35mm are coming! But when? 

The three zooms I tested are all โ€œLโ€ lenses, designating them as premium-performance models. I have not tested any of Canonโ€™s โ€œeconomyโ€ line of RF lenses, such as their 24mm and 35mm Macro STM primes. Tests Iโ€™ve seen suggest they donโ€™t offer the sharpness I desire for most astrophotography. 

Contributing to the lack of choice, top-quality third-party lenses from the likes of Sigma (such as their new 20mm and 24mm Art lenses made for mirrorless cameras) have yet to appear in Canon RF mount versions. Will they ever? In moves that evoked much disdain, Samyang and Viltrox were both ordered by Canon to cease production of their RF auto-focus lenses. 

For their mirrorless R cameras, Canon has not authorized any third-party lens makers, forcing you to buy costly Canon L glass, or settle for their lower-grade STM lenses, or opt for reverse-engineered manual-focus lenses from makers such as TTArtisan and Laowa/Venus Optics. While they are good, they are not up to the optical standards of Canonโ€™s L-series glass.

I know, as I own several RF-mount TTArtisan wide-angle lenses and the Laowa 15mm f/2 lens. You can find my tests of those lenses at AstroGearToday.com. Look under Reviews: Astrophotography Gear. 

RF lenses will fit only on Canon R-series mirrorless cameras. This shows the RF15-35mm on the Canon R5 used for the lens testing. 

The trio of RF lenses tested here work on all Canon EOS R-series cameras, including their R7 and R10 cropped-frame cameras. However, they will not work on any Canon DSLRs. 

Two of the lenses, the RF15-35mm F/2.8 and RF70-200mm F/4, are designs updated from older Canon DSLR lenses with similar specs. The RF28-70mm F/2 does not have an equivalent focal length range and speed in Canonโ€™s DSLR lens line-up. Indeed, nobody else makes a lens this fast covering the โ€œnormalโ€ zoom range. 

Together, the three lenses cover focal lengths from 15mm to 200mm, with some overlap. A trio of zooms like this โ€” a wide-angle, normal, and telephoto โ€” is often called a โ€œholy trinityโ€ set, a popular combination all camera manufacturers offer to cover the majority of applications. 

However, my interest was strictly for astrophotography, with stars the test subjects.  

NOTE: CLICK or TAP on a test image to download a full-resolution image for closer inspection. The images, while low-compression JPGs, are large and numerous, and so will take time to fully load and display. Patience! 

All images are ยฉ 2022 by Alan Dyer/AmazingSky.com. Use without permission is prohibited.


METHODOLOGY

I tested the trio of lenses on same-night exposures of a starry but moonlit sky, using the 45-megapixel Canon R5 camera mounted on a motorized star tracker to follow the rotating sky. With one exception noted, any distortion of stars from perfect pinpoints is due to lens aberrations, not star trailing. The brighter moonlit sky helped reveal non-uniform illumination from lens vignetting. 

I shot each lens wide-open at its maximum aperture, as well as one stop down from maximum, to see how aberrations and vignetting improved. 

I did not test auto-focus performance, nor image stabilization (only the RF28-70mm lacks internal IS), nor other lens traits unimportant for astro work such as bokeh or close focus image quality.

I also compared the RF15-35mm on same-night dark-sky tests against a trio of prime lenses long in my stable: the Rokinon 14mm SP, and Canonโ€™s older L-series 24mm and 35mm primes, all made for DSLRs.


The lenses each come with lens hoods that use a click-on mechanism much easier to twist on and off than with the older design used on Canon EF lenses.

TL;DR SUMMARY

  • Each of the Canon โ€œholy trinityโ€ of zoom performs superbly, though not without some residual lens aberrations such as corner astigmatism and, in the RF28-70mm, slight chromatic aberration at f/2. 
  • However, what flaws they show are well below the level of many older prime lenses made for DSLR cameras. 
  • The RF lensesโ€™ major optical flaw is vignetting, which can be quite severe at some focal lengths, such as in the RF70-200mm at 200mm. But this flaw can be corrected in processing. 
  • These are lenses that can replace fixed-focal length primes, though at considerable cost, in part justifiable in that they negate the need for a suite of many prime lenses.
  • The performance of these and other new lenses made for mirrorless cameras from all brands is one good reason to switch from DSLR to mirrorless cameras. 

Lens Specs and Applications 

Canon RF15-35mm F/2.8 L IS USM

The RF15-35mm is a fine nightscape lens. It extends slightly when zooming with the lens physically longest at its shortest 15mm focal length. 

The Canon RF15-35mm F/2.8 L is made primarily for urban photography and landscapes by day. My main application is using it to take landscapes by night, and auroras, where its relatively fast f/2.8 speed helps keeps exposure times short and ISO speeds reasonably low. However, the RF15-35mm can certainly be used for tracked wide-angle Milky Way and constellation portraits. 

The lens weighs a moderate 885 grams (31 ounces or 1.9 pounds) with lens hood and end caps, and accepts 82mm filters, larger than the 72mm or 77mm filter threads of most astrophoto-friendly lenses. Square 100mm filters will work well on the lens, even at the 15mm focal length. There are choices, such as from KASE, for light pollution reduction and star diffusion filters in this size and format. I have reviews of these filters at AstroGearToday.com, both here for light pollution filters and here for starglow filters

Canon offers a lower-cost alternative in this range, their RF14-35mm. But it is f/4, a little slow for nightscape, aurora, and Milky Way photography. I have not tested one. 

Canon RF28-70mm F/2 L USM

The RF28-70mm works great for tracked starfields and constellations. It extends when zooming, with it longest at its 70mm focal length. 

The big Canon RF28-70mm F/2 is aimed at wedding and portrait photographers, though the lens is suitable for landscape work. While I do use it for nightscapes, my primary use is for tracked Milky Way and constellation images, where its range of fields of view nicely frames most constellations, from big to small. 

I justified its high cost by deciding it replaces (more or less!) prime lenses in the common 24mm, 35mm, 50mm, and 85mm focal lengths. Its f/2 speed does bring it into fast prime lens territory. Itโ€™s handy to have just one lens to cover the range.

Canon offers a lower-cost alternative here, too, their RF24-70mm. But it is f/2.8. While this is certainly excellent speed, I like having the option of shooting at f/2. An example is when using narrowband nebula filters such as red hydrogen-alpha filters, where shooting at f/2 keeps exposures shorter and/or ISOs lower when using such dense filters. I use this lens with an Astronomik 12-nanometre H-ฮฑ clip-in filter. An example is in one of the galleries below. 

While a clip-in filter shifts the infinity focus point inward (to as close as the 2-metre mark with the RF28-70mm at 28mm, and to 6 metres at 70mm), I did not find that shift adversely affected the lensโ€™s optical performance. Thatโ€™s not true of all lenses.

Make no mistake, the RF28-70mm is one hefty lens, weighing 1530 grams (54 ounces or 3.4 pounds). Its front-heavy mass demands a solid tripod head. Its large front lens accepts big 95mm filters, a rare size with few options available. I found one broadband light pollution filter in this size, from URTH. Otherwise, you need to use in-body clip-in filters. Astronomik makes a selection for Canon EOS R cameras.

Canon RF70-200mm F/4 L IS USM

The RF70-200mm works well for closeups of landscape scenes such as moonrises. It extends the most of all the lenses when zooming to its longest focal length. 

The Canon RF70-200mm F/4 is another portrait or landscape lens. I use it primarily for bright twilight planet conjunctions and moonrise scenes, where its slower f/4 speed is not a detriment. However, as my tests show, it can be used for tracked deep-sky images, where it is still faster than most short focal length telescopes. 

The RF70-200mm lens weighs 810 grams (28 ounces, or 1.75 pounds) with lens hood and caps, so is light for a 70-to-200mm zoom. It is also compact. At just 140mm long when set to 70mm, it is actually the shortest lens of the trio. However, the barrel extends to 195mm long when zoomed out to 200mm focal length. 

Canon offers the more costly and, at 1200 grams, heavier RF70-200mm F/2.8 lens which might be a better choice for deep-sky imaging where the extra stop of speed can be useful. But in this case, I chose the slower, more affordable โ€“ though still not cheap โ€“ f/4 version. It accepts common 77mm filters, as does the f/2.8 version. 


Centre Sharpness

Canon RF15-35mm F/2.8 L IS USM

This compares 400% blow-ups of the frame centres at the two extreme focal lengths and at two apertures: wide open at f/2.8 and stopped down to f/4. 

Like the other two zoom lenses tested, the RF15-35mm is very sharp on axis. Even wide open, thereโ€™s no evidence of softness and star bloat from spherical aberration, the bane of cheaper lenses. 

Coloured haloes from longitudinal chromatic aberration are absent, except at 28mm and 35mm (shown here) when wide open at f/2.8, where bright stars show a little bit of blue haloing. At f/4, this minor level of aberration disappears.

Canon RF28-70mm F/2 L USM

This compares 400% blow-ups of the frame centres at the two extreme focal lengths and at two apertures: wide open at f/2 and stopped down to f/2.8.

The big RF28-70mm is also very sharp on-axis but is prone to more chromatic aberration at f/2, showing slight magenta haloes on bright stars at the shorter focal lengths and pale cyan haloes at 70mm in my test shots. Such false colour haloes can be very sensitive to precise focus, though with refractive optics the point of least colour is often not the point of sharpest focus. 

At f/2, stars are a little softer at 70mm than at 28mm. Stopping down to f/2.8 eliminates this slight softness and most of the longitudinal chromatic aberration. 

Canon RF70-200mm F/4 L IS USM

This compares 400% blow-ups of the frame centres at the two extreme focal lengths and at two apertures: wide open at f/4 and stopped down to f/5.6.

Unlike prime telephotos Iโ€™ve used, the RF70-200mm shows negligible chromatic aberration on-axis at all focal lengths, even at f/4. Stars are a little softer at the longest focal length at f/4, perhaps from slight spherical aberration, though my 200mm test shots are also affected by a little mistracking, trailing the stars slightly. 

Stopping down to f/5.6 sharpens stars just that much more at 200mm. 


Corner Aberrations

The corners are where we typically separate great lenses from the merely good. And it is where zoom lenses have traditionally performed badly. For example, my original Canon EF16-35mm f/2.8 lens was so bad off-axis I found it mostly unusable for astro work. Not so the new RF15-35mm, which is the RF replacement for Canonโ€™s older EF16-35mm.

To be clear โ€“ in these test shots you might think the level of aberrations are surprising for premium lenses. But keep in mind, to show them at all I am having to pixel-peep by enlarging all the test images by 400 percent, cropping down to just the extreme corners. 

Check the examples in the Compared to DSLR Lenses section and in the Finished Images Galleries for another look at lens performance in broader context. 

Canon RF15-35mm F/2.8 L IS USM

This compares 400% blow-ups of the extreme corners at five focal lengths with the RF15-35mm wide open at f/2.8

Surprisingly, this RFโ€™s best performance off-axis is actually at its shortest focal length. At 15mm it exhibits only some slight tangential astigmatism, elongating stars away from the frame centre. At 24mm aberrations appear slightly worse than at the other focal lengths, showing some flaring from sagittal astigmatism and perhaps coma as well, aberrations seen to a lesser degree at 28mm and 35mm, making stars look like little three-pointed triangles. 

This compares 400% blow-ups of the extreme corners at five focal lengths with the RF15-35mm stopped down one stop to f/4.

The aberrations reduce when stopped down to f/4, but are still present, especially at 24mm, this lensโ€™s weakest focal length, though only just. 

While the RF15-35mm isnโ€™t perfect, it outperforms other prime lenses I have, and that I suspect most users will own or have used in the past with DSLRs. Only new wide-angle premium primes for the RF mount, if and when we see them, will provide better performance. 

Canon RF28-70mm F/2 L USM

This compare 400% blow-ups of the extreme corners at four focal lengths with the RF28-70mm wide open at f/2.

The RF28-70mmโ€™s fast f/2 speed, unusual for any zoom lens, was surely a challenge to design for. Off-axis when wide open at f/2 it does show astigmatism at the extreme corners at all focal lengths, but the least at 50mm, and the worst at 28mm where a little lateral chromatic aberration is also visible, adding slight colour fringing. 

This compare 400% blow-ups of the extreme corners at four focal lengths with the RF28-70mm stopped down one stop to f/2.8.

Sharpness off-axis improves markedly when stopped down one stop to f/2.8, where at 50mm stars are now nearly perfect to the corners. Indeed, performance is so good at 50mm, I think there would be little need to buy the Canon RF50mm prime, unless its f/1.2 speed is deemed essential. 

With the RF28-70mm at f/2.8, stars still show some residual astigmatism at 28mm and 35mm, but only at the extreme corners. 

Canon RF70-200mm F/4 L IS USM

This compare 400% blow-ups of the extreme corners at four focal lengths with the RF70-200mm wide open at f/4.

The RF70-200mm telephoto zoom shows some astigmatism and coma at the corners when wide open at f/4, with it worse at the shorter focal lengths. While lens corrections have been applied here, the 200mm image still shows a darker corner from the vignetting described below. 

This compare 400% blow-ups of the extreme corners at four focal lengths with the RF70-200mm stopped down one stop to f/5.6.

Stopping down to f/5.6 eliminates most of the off-axis aberrations at 135mm and 200mm focal lengths but some remain at 70mm and to a lesser degree at 100mm. 

This is a lens that can be used at f/4 even for the demands of deep-sky imaging, though perfectionists will want to stop it down. At f/5.6 it is similar in speed to many astrographic refractors, though most of those start at about 250mm focal length. 


Frame Vignetting

In the previous test images, I applied lens corrections (but no other adjustments) to each of the raw files in Adobe Camera Raw, using the settings ACR automatically selects from its lens database. These corrections brightened the corners.

In this next set I show the lensesโ€™ weakest point, their high level of vignetting. This light falloff darkens the corners by a surprising amount. In the new generation of lenses for mirrorless cameras, it seems lens designers are choosing to sacrifice uniform frame illumination in order to maximize aberration corrections. The latter canโ€™t be corrected entirely, if at all, by software. 

However, corrections applied either in-camera or at the computer can brighten corners, โ€œflatteningโ€ the field. I show that improvement in the section that follows this one.

Canon RF15-35mm F/2.8 L IS USM

This compares the level of vignetting present in the RF15-35mm without the benefit of lens corrections, showing the difference at five focal lengths. 

In the wide-angle zoom, vignetting darkens just the corners at 15mm, but widens to affect progressively more of the frame at the longer focal lengths. The examples show the entire right side of the frame. I show the effect just at f/2.8. 

Though I donโ€™t show examples with the two wider zooms, with all lenses vignetting decreases dramatically when each lens is stopped down by even one stop. The fields become much more evenly illuminated, though some darkening at the very corners remains one stop down.

Canon RF28-70mm F/2 L USM

This compares the level of vignetting present in the RF28-70mm without the benefit of lens corrections, showing the difference at four focal lengths.

In this โ€œnormalโ€ zoom, vignetting performance is similar at all focal lengths, though it affects a bit more of the field at 70mm than at 28mm. Again, while Iโ€™m not presenting an example, vignetting decreases a lot when this lens is stopped down to f/2.8. While the extra stop of speed is certainly nice to have at times, I usually shoot the RF28-70mm at f/2.8.

Canon RF70-200mm F/4 L IS USM

This compares the level of vignetting present in the RF70-200mm without the benefit of lens corrections, showing the difference at four focal lengths.

In this telephoto zoom, vignetting is fairly mild at the shorter focal lengths but becomes severe at 200mm, affecting much of the field. It is far worse than I see with my older Canon EF200mm f/2.8 prime, a lens that is not as sharp at f/4 as the RF zoom. 

The faster RF70-200mm f/2.8 lens, which I had the chance to test one night last year, showed as much, if not more, vignetting than the f/4 version. See my test here at AstroGearToday.com. I thought the f/4 version would be better for vignetting, but it is not.

This shows how much the RF-70-200mmโ€™s vignetting improves when it is stopped down.

In this case, as the vignetting is so prominent at 200mm, I show above how much it improves when stopped down to f/5.6, in a comparison with the lens at f/4, both with no lens corrections applied in processing. The major improvement comes from the smaller aperture alone. For twilight scenes, Iโ€™d suggest stopping this lens down to better ensure a uniform sky background. 


LENS Corrections

In this next set I show how well applying lens corrections improves the vignetting at the focal lengths where each of the lenses is at its worse, and with each at its widest aperture. 

I show this with Adobe Camera Raw but Lightroom would provide identical results. I did not test lens corrections with other programs such as CaptureOne, DxO PhotoLab, or ON1 Photo Raw, which all have automatic lens corrections as well.

Canon RF15-35mm F/2.8 L IS USM

This compare the RF15-35mm lens at f/2.8 and 35mm with and without lens corrections applied, to show how much they improve the vignetting. 

Applying lens corrections in Adobe Camera Raw certainly brightened the corners and edges, though still left some darkening at the very corners that can be corrected by hand in the Manual tab. 

Canon RF28-70mm F/2 L USM

This compare the RF28-70mm lens at f/2 and 70mm with and without lens corrections applied, to show how much they improve the vignetting.

ACRโ€™s lens corrections helped but did not completely eliminate the vignetting here. Corner darkening remained. Manually increasing the vignetting slider can provide that extra level of correction needed. 

Canon RF70-200mm F/4 L IS USM

This compare the RF70-200mm lens at f/4 and 200mm with and without lens corrections applied, to show how much they improve the vignetting.

The high level of vignetting with this lens at 200mm largely disappeared with lens corrections, though not entirely. For deep-sky imaging, users might prefer to shoot and apply flat-field frames. I prefer to apply automatic and manual corrections to the raw files, to stay within a raw workflow as much as possible. 


Same Focal Length Comparisons

With the trio of lenses offering some of the same focal lengths, here I show how they compare at three of those shared focal lengths. I zoom into the upper right corners here, as with the Corner Aberrations comparisons above. 

RF15-35mm vs. RF28-70mm at 28mm

This compares the RF15-35mm at 28mm to the RF28-70mm also at 28mm and with both at f/2.8.

With both lenses at 28mm and at the same f/2.8 aperture (though the RF28-70mm is now stopped down one stop), itโ€™s a toss up. Both show corner aberrations, though of a different mix, distorting stars a little differently. The RF28-70mm shows some lateral chromatic aberration, but the RF15-35mm shows a bit more flaring from astigmatism. 

RF15-35mm vs. RF28-70mm at 35mm

This compares the RF15-35mm at 35mm to the RF28-70mm also at 35mm and with both at f/2.8.

The story is similar with each lens at 35mm. Stars seem a bit sharper in the RF15-35mm though are elongated more by astigmatism at the very corners. Lens corrections have been applied here and with the other two-lens comparison pairs. 

RF28-70mm vs. RF70-200mm at 70mm

This compares the RF28-70mm at 70mm and f/2.8 to the RF70-200mm also at 70mm but wide open at f/4.

Here I show the RF28-70mm at f/2.8 and the RF70-200mm wide open at f/4, with both set to 70mm focal length. The telephoto lens shows a little more softening and star bloating from corner aberrations, though both perform well.


Compared to DSLR Lenses

Here I try to demonstrate just how much better at least one of the zooms on test here is compared to older prime lenses made for DSLRs. The Canon lenses are labeled EF, for Canonโ€™s EF lens mount used for decades on their DSLRs and EOS film cameras. Both are premium L lenses. 

I shot this set on a different night than the previous examples, with some light cloud present which added various amounts of glows around stars. But the test shots still show corner sharpness and aberrations well, in this case of the upper left corners of all frames. 

Canon RF15-35mm at 35mm vs. Canon EF35mm L

This compares the RF15-35mm zoom at 35mm to the older EF35mm L prime lens. Some light cloud added the glows at right.

The Canon EF35mm is the original Mark I version, which Canon replaced a few years ago with an improved Mark II model. So Iโ€™m sure if you were to buy an EF35mm lens now (or if thatโ€™s the model you own) it will perform better than what I show here. 

Both lenses are at f/2.8, wide open for the RF lens, but stopped down two stops for the f/1.4 EF lens. 

The zoom lens is much sharper to the corners, with far less astigmatism and none of the lateral chromatic aberration and field curvature (softening stars at the very corner) of the old EF35mm prime. I thought the EF35mm was a superb lens, and used it a lot over the last 15 years for Milky Way panoramas. I would not use it now! 

Canon RF15-35mm at 24mm vs. Canon EF24mm L

This compares the RF15-35mm zoom at 24mm to the older EF24mm L prime lens. Some light cloud added the glows at right.

Bought in the early years of DSLRs, the EF24mm tested here is also an original Mark I model, since replaced by an improved Mark II 24mm. The old 24mm is good, but shows more astigmatism than the RF lens, and some field curvature and purple chromatic aberration not present at all in the RF lens. 

And this is comparing it to the RF lens at its weakest focal length, 24mm. It still handily outperforms the old EF24mm prime. 

Canon RF15-35mm at 15mm vs. Rokinon 14mm SP

This compares the RF15-35mm at 15mm to the Rokinon 14mm SP prime lens.

Canon once made an EF14mm f/2.8 L prime, but Iโ€™ve never used it. For a lens in this focal length, one popular with nightscape photographers, Iโ€™ve used the ubiquitous Rokinon/Samyang 14mm f/2.8 manual lens. While a bargain at about $300, I always found it soft and aberrated at the corners. See my test of 14mm ultra-wides here

A few years ago I upgraded to the Rokinon 14mm f/2.4 lens in their premium SP series (about $800 for the EF-mount version). While a manual lens, it does have electrical contacts to communicate lens metadata to the camera. Like all EF-mount lenses from any brand, it can be adapted to Canon R cameras using Canonโ€™s $100 EF-EOS R lens adapter.

Older DSLR lenses like the Rokinon SP can be adapted to all Canon R cameras with the Canon lens adapter ring which transmits lens data to the camera. 

The Rokinon SP is the only prime I found that beat the RF zoom. It provided sharper images to the corners than the RF15-35mm at 15mm. The Rokinon also offers the slightly faster maximum aperture of f/2.4 (which Canon cameras register as f/2.5). Vignetting is severe, but like the RF lenses can be corrected โ€“ Camera Raw has this lens in its database. What is not so easy to correct is some slight colour shift at the corners.

Another disadvantage, as with many other 14mm lenses, is that the SP lens cannot accept front-mounted filters. The RF15-35mm can. 

Nevertheless, until Canon comes out with a 12mm to 14mm RF prime, or allows Sigma to, an adapted Rokinon 14mm SP is a good affordable alternative to the RF15-35mm.


The RF15-35mm (left) takes 82mm filters, the RF28-70mm (centre) requires 95mm filters, but the RF70-200mm (right) can accept common 77mm filters. 

Mechanical Points

  • All the RF lens bodies are built of weight-saving engineered plastic incorporating thorough weather sealing. There is nothing cheap about their fit, finish or handling. Each lens has textured grip rings for the zoom, focus and a control ring that can be programmed to adjust either aperture, ISO, exposure compensation or other settings of your choosing. 
  • As with all modern auto-focus lenses, the manual focus ring on each lens does not mechanically move glass. It controls a motor that in turn focuses the lens, so-called โ€œfocus-by-wire.โ€ However, I found that focus could be dialled in accurately. But if the camera is turned off, then on again, the lens will not return to its previous focus position. You have to refocus to infinity each time the camera is powered up, a nuisance. 
  • Unlike some Nikon, Sony, Samyang, and Sigma lenses, none of the Canon lenses have a focus lock button, or any way of presetting an infinity focus point, or simply having the lens remember where it was last set. I would hope Canon could address that deficiency in a firmware update. 
  • With all the zooms, I did not find any issue with โ€œzoom creep.โ€ The telescoping barrels  remained in place during long exposures and did not slowly retract when aimed up. While the RF28-70mm and RF70-200mm each have a zoom lock switch, it locks the lens only at its shortest focal length. 
  • Each lens is parfocal within its zoom range. Focus at one zoom position, and it will be in focus for all the focal lengths. I usually focus at the longest focal length where it is easiest to judge focus by eye, then zoom out to frame the scene. 

FINISHED IMAGES GALLERIES

Here I present a selection of final, processed images (four for each lens), so you can better see how each performs on real-world celestial subjects. To speed download, the images are downsized to 2048 pixels wide.

As per my comments at top, the RF15-35mm is my primary nightscape lens, the RF28-70mm my lens for wide-field constellation and Milky Way shots, while the RF70-200mm is for conjunctions and Moon scenes. It would also be good for eclipses.

Image Gallery with Canon RF15-35mm F/2.8 L IS USM

Image Gallery with Canon RF28-70mm F/2 L USM

Image Gallery with Canon RF70-200mm F/4 L IS USM


CONCLUSIONs and recommendations

If you are a Canon user switching from your aging but faithful DSLR to one of their mirrorless R cameras, each of these lenses will perform superbly for astrophotography. At a price! Each is costly. But the cost of older EF lenses has also increased in recent months. 

The other native RF L-series lenses in this focal length range, Canonโ€™s RF50mm and RF85mm f/1.2 primes, are stunning โ€ฆ but also expensive. As Iโ€™m sure any coming RF wide-angle L primes will be, if and when they ever appear! 

This shows the relative difference in size and height of the lens trio, with all collapsed to their minimum size. 

The cheaper alternative โ€“ not the least because you might already own them! โ€“ is using adapted EF-mount lenses made for DSLRs, either from Canon or other brands. But in many cases, as Iโ€™ve shown, the new RF glass is sharper, especially when on a high-resolution camera such as the Canon R5 I used for all the testing. 

And thereโ€™s the harsh reality that Canon is discontinuing many EF lenses. You can now buy some only used. For example, the EF135mm f/2 L and EF200mm f/2.8 L are both gone. 

Until Canon licenses other companies to issue approved lenses for their RF mount โ€“ if that happens at all โ€“ our choices for native RF lenses are limited. However, the quality of Canonโ€™s L lenses is superb. I now use these zooms almost exclusively, and financed most of their considerable cost by selling off a ream of older cameras and lenses. 

If thereโ€™s one lens to buy for most astrophotography, it might be the big RF28-70mm F/2, a zoom lens that comes close to offering it all: flexibility, optical quality and speed. The RF24-70mm F/2.8 is a more affordable choice, though I have not tested one. 

If nightscapes are the priority, the RF15-35mm F/2.8 would see a lot of use, as perhaps the only lens youโ€™d need. 

Of the trio, the RF70-200mm was the lowest priority on my wish list. But it has proven to be very useful for framing horizon scenes. 

The superb optics of these and other new lenses made for mirrorless cameras is one good reason to upgrade from a DSLR to a mirrorless camera, in whatever brand you prefer.

โ€” Alan, September 21, 2022 / ยฉ 2022 Alan Dyer / AmazingSky.com ย 

All images are ยฉ 2022 by Alan Dyer/AmazingSky.com. Use without permission is prohibited.

Testing the Canon R6 for Astrophotography


In an extensive technical blog, I put the Canon R6 mirrorless camera through its paces for the demands of astrophotography. 

Every major camera manufacturer, with the lone exception of stalwart Pentax, has moved from producing digital lens reflex (DSLR) cameras, to digital single lens mirrorless (DSLM) cameras. The reflex mirror is gone, allowing for a more compact camera, better movie capabilities, and enhanced auto-focus functions, among other benefits. 

But what about for astrophotography? I reviewed the Sony a7III and Nikon Z6 mirrorless cameras here on my blog and, except for a couple of points, found them excellent for the demands of most astrophotography. 

For the last two years Iโ€™ve primarily used Canonโ€™s astro-friendly and red-sensitive EOS Ra mirrorless, a model sadly discontinued in September 2021 after just two years on the market. I reviewed that camera in the April 2020 issue of Sky & Telescope magazine, with a quick first look here on my blog

The superb performance of the Ra has prompted me to stay with the Canon mirrorless R system for future camera purchases. Here I test the mid-priced R6, introduced in August 2020.


NOTE: In early November 2022 Canon announced the EOS R6 MkII, which one assumes will eventually replace the original R6 once stock of that camera runs out. The MkII has a 24 Mp sensor for slightly better resolution, and offers longer battery life. But the main improvements over the R6 is to autofocus accuracy, a function of little use to astrophotographers. Only real-world testing will tell if the R6 MkII has better or worse noise levels than the R6, or has eliminated the R6’s amp glow, reported on below.


CLICK or TAP on an image to bring it up full screen for closer inspection. All images are ยฉ 2021 by Alan Dyer/AmazingSky.com. Use without permission is prohibited.

M31, the spiral galaxy in Andromeda, with the Canon R6 mirrorless camera. It is a stack of 8 x 8-minute exposures at ISO 800, blended with a stack of 8 x 2-minute exposures at ISO 400 for the core, to prevent it from overexposing too much, all with a SharpStar 76mm apo refractor at f/4.5 with its field flattener/reducer.

TL;DR SUMMARY

The Canon R6 has proven excellent for astrophotography, exhibiting better dynamic range and shadow recovery than most Canon DSLRs, due to the ISO invariant design of the R6 sensor. It is on par with the low-light performance of Nikon and Sony mirrorless cameras. 

The preview image is sensitive enough to allow easy framing and focusing at night. The movie mode produces usable quality up to ISO 51,200, making 4K movies of auroras possible. Canon DSLRs cannot do this. 

Marring the superb performance are annoying deficiencies in the design, and one flaw in the image quality โ€“ an amp glow โ€“ that particularly impacts deep-sky imaging.

R6 pros

The Canon R6 is superb for its:

  • Low noise, though not exceptionally so
  • ISO invariant sensor performance for good shadow recovery 
  • Sensitive live view display with ultra-high ISO boost in Movie mode 
  • Relatively low noise Movie mode with full frame 4K video
  • Low light auto focus and accurate manual focus assist  
  • Good battery life 

R6 cons

The Canon R6 is not so superb for its:

Design Deficiencies 

  • Lack of a top LCD screen
  • Bright timer display in Bulb on the rear screen
  • No battery level indication when shooting 
  • Low grade R3-style remote jack, same as on entry-level Canon DSLRs 

Image Quality Flaw

  • Magenta edge โ€œamp glowโ€ in long exposures 
The Canon Ra on the left with the 28-70mm f/2 RF lens and the Canon R6 on the right with the 70-200mm f/2/8 RF lens, two superb but costly zooms for the R system cameras.

CHOOSING THE R6

Canonโ€™s first full-frame mirrorless camera, the 30-megapixel EOS R, was introduced in late 2018 to compete with Sony. As of late-2021 the main choices in a Canon DSLM for astrophotography are either the original R, the 20-megapixel R6, the 26-megapixel Rp, or the 45-megapixel R5. 

The new 24-megapixel Canon R3, while it has impressive low-noise performance, is designed primarily for high-speed sports and news photography. It is difficult to justify its $6,000 cost for astro work. 

I have not tested Canonโ€™s entry-level, but full-frame Rp. While the Rpโ€™s image quality is likely quite good, its small battery and short lifetime on a single charge will be limiting factors for astrophotography. 

Nor have I tested the higher-end R5. Friends who use the R5 for nightscape work love it, but with smaller pixels the R5 will be noisier than the R6, which lab tests at sites such as DPReview.com seem to confirm. 

Meanwhile, the original EOS R, while having excellent image quality and features, is surely destined for replacement in the near future โ€“ with a Canon EOS R Mark II? The Rโ€™s successor might be a great astrophoto camera, but with the Ra gone, I feel the R6 is currently the prime choice from Canon, especially for nightscapes.

I tested an R6 purchased in June 2021 and updated in August with firmware v1.4. Iโ€™ll go through its performance and functions with astrophotography in mind. Iโ€™ve ignored praised R6 features such as eye tracking autofocus, in-body image stabilization, and high speed burst rates. They are of limited or no value for astrophotography. 

Along the way, I also offer a selection of user tips, some of which are applicable to other cameras. 

LIVE VIEW FOCUSING AND FRAMING

“Back-of-the-camera” views of the R6 in its normal Live View mode (upper left) and its highly-sensitive Movie Mode (upper right), compared to views with four other cameras. Note the Milky Way visible with the R6 in its Movie mode, similar to the Sony in Bright Monitoring mode.

The first difference you will see when using any new mirrorless camera, compared to even a high-end DSLR, is how much brighter the โ€œLive Viewโ€ image is when shooting at night. DSLM cameras are always in Live View โ€“ even the eye-level viewfinder presents a digital image supplied by the sensor. 

As such, whether on the rear screen on in the viewfinder, you see an image that closely matches the photo you are about to take, because it is the image you are about to take. 

To a limit. DSLMs can do only so much to simulate what a long 30-second exposure will look like. But the R6, like many DSLMs, goes a long way in providing a preview image bright enough to frame a dark scene and focus on bright stars. Turn on Exposure Simulation to brighten the live image, and open the lens as wide as possible. 

The Canon R6 in its Movie Mode at ISO 204,800 and with a lens wide open.

But the R6 has a trick up its sleeve for framing nightscapes. Switch the Mode dial to Movie, and set the ISO up to 204,800 (or at night just dial in Auto ISO), and with the lens wide open and shutter on 1/8 second (as above), the preview image will brighten enough to show the Milky Way and dark foreground, albeit in a noisy image. But itโ€™s just for aiming and framing.

This is similar to the excellent, but well-hidden Bright Monitoring mode on Sony Alphas. This high-ISO Movie mode makes it a pleasure using the R6 for nightscapes. The EOS R and Ra do not have this ability. While their live view screens are good, they are not as sensitive as the R6โ€™s, with the R and Ra’s Movie modes able to go up to only ISO 12,800. The R5 can go up to “only” ISO 51,200 in its Movie mode, good but not quite high enough for live framing on dark nights. 

Comparing Manual vs. Auto Focus results with the R6.

The R6 will also autofocus down to a claimed EV -6.5, allowing it to focus in dim light for nightscapes, a feat impossible in most cameras. In practice with the Canon RF 15-35mm lens at f/2.8, I found the R6 canโ€™t autofocus on the actual dark landscape, but it can autofocus on bright stars and planets (provided, of course, the camera is fitted with an autofocus lens). 

Autofocusing on bright stars proved very accurate. By comparison, while the Ra can autofocus on distant bright lights, it fails on bright stars or planets. 

Turning on Focus Peaking makes stars turn red, yellow or blue (your choice of colours) when they are in focus, as a reassuring confirmation. 

The Focus Peaking and Focus Guide menu.
The R6 live view display with Focus Guide arrows on and focused on a star, Antares.

In manual focus, an additional Focus Aid overlay provides arrows that close up and turn green when in focus on a bright star or planet. Or you can zoom in by 5x or 10x to focus by eye the old way by examining the star image. I wish the R6 had a 15x or 20x magnification; 5x and 10x have long been the Canon standards. Only the Ra offered 30x for ultra-precise focusing on stars. 

In all, the ease of framing and focusing will be the major improvement youโ€™ll enjoy by moving to any mirrorless, especially if your old camera is a cropped-frame Canon Rebel or T3i! But the R6 particularly excels at ease of focusing and framing. 

NOISE PERFORMANCE

The key camera characteristic for astrophoto use is noise. I feel it is more important than resolution. Thereโ€™s little point in having lots of fine detail if it is lost in a blizzard of high-ISO noise. And for astro work, we are almost always shooting at high ISOs.

Comparing the R6’s noise at increasingly higher ISO speeds on a starlit nightscape.

With just 20 megapixels, low by todayโ€™s standards, the R6 has individual pixels, or more correctly โ€œphotosites,โ€ that are each 6.6 microns in size, the โ€œpixel pitch.โ€ 

By comparison, the 30-megapixel R (and Ra) has a pixel pitch of 5.4 microns, the 45-megapixel R5โ€™s pixel pitch is 4.4 microns, while the acclaimed low-light champion in the camera world, the 12-megapixel Sony a7sIII, has large 8.5-micron photosites. 

The bigger the photosites (i.e. the larger the pixel pitch), the more photons each photosite can collect in a given amount of time โ€“ and the more photons they can collect, period, before they overfill and clip highlights. More photons equals more signal, and therefore a better signal-to-noise ratio, while the greater โ€œfull-well depthโ€ yields higher dynamic range. 

Each generation of camera also improves the signal-to-noise ratio by suppressing noise via its sensor design and improved signal processing hardware and firmware. The R6 uses Canonโ€™s latest DIGIC X processor shared by the companyโ€™s other mirrorless cameras. 

Comparing the R6 noise with the 6D MkII and EOS Ra on a deep-sky subject, galaxies.

In noise tests comparing the R6 against the Ra and Canon 6D Mark II, all three cameras showed a similar level of noise at ISO settings from 400 up to 12,800. But the 6D Mark II performed well only when properly exposed. Both the R6 and Ra performed much better for shadow recovery in underexposed scenes. 

Comparing the R6 noise with with the 6D MkII and EOS Ra on a shadowed nightscape.
Comparing the R6 noise with the EOS Ra on the Andromeda Galaxy at typical deep-sky ISO speeds.

In nightscapes and deep-sky images the R6 and Ra looked nearly identical at each of their ISO settings. This was surprising considering the Raโ€™s smaller photosites, which perhaps attests to the low noise of the astronomical โ€œaโ€ model. 

Or it could be that the R6 isnโ€™t as low noise as it should be for a 20 megapixel camera. But it is as good as it gets for Canon cameras, and thatโ€™s very good indeed.

I saw no โ€œmagic ISOโ€ setting where the R6 performed better than at other settings. Noise increased in proportion to the ISO speed. It proved perfectly usable up to ISO 6400, with ISO 12,800 acceptable for stills when necessary. 

ISO INVARIANCY

The flaw in many Canon DSLRs, one documented in my 2017 review of the 6D Mark II, was their poor dynamic range due to the lack of an ISO invariant sensor design. 

The R6, as with Canonโ€™s other R-series cameras, has largely addressed this weakness. The sensor in the R6 appears to be nicely ISO invariant and performs as well as the Sony and Nikon cameras I have used and tested, models praised for their ISO invariant behaviour. 

Where this trait shows itself to advantage is on nightscapes where the starlit foreground is often dark and underexposed. Bringing out detail in the shadows in raw files requires a lot of Shadow Recovery or increasing the Exposure slider. Images from an ISO invariant sensor can withstand the brightening โ€œin postโ€ far better, with minimal noise increase or degradations such as a loss of contrast, added banding, or horrible discolourations. 

Comparing the R6 for ISO Invariancy on a starlit nightscape.

To test the R6, I shot sets of images at the same shutter speed, one well-exposed at a high ISO, then several at successively lower ISOs to underexpose by 1 to 5 stops. I then brightened the underexposed images by increasing the Exposure in Camera Raw by the same 1 to 5 stops. In an ideal ISO invariant sensor, all the images should look the same. 

The R6 did very well in images underexposed by up to 4 stops. Images underexposed by 5 stops started to fall apart, but Iโ€™ve seen that in Sony and Nikon images as well. 

Comparing the R6 for ISO Invariancy on a moonlit nightscape.

This behaviour applies to images underexposed by using lower ISOs than what a โ€œnormalโ€ exposure might require. Underexposing with lower ISOs can help maintain dynamic range and avoid highlight clipping. But with nightscapes, foregrounds can often be too dark even when shot at an ISO high enough to be suitable for the sky. Foregrounds are almost always underexposed, so good shadow recovery is essential for nightscapes, and especially time-lapses, when blending in separate longer exposures for the ground is not practical.

With its improved ISO invariant sensor, the R6 will be a fine camera for nightscape and time-lapse use, which was not true of the 6D Mark II. 

For those interested in more technical tests and charts, I refer you to DxOMarkโ€™s report on the Canon R6.  

Comparing R6 images underexposed in 1-stop increments by using shorter shutter speeds.
Comparing R6 images underexposed in 1-stop increments by using smaller apertures.

However, to be clear, ISO invariant behaviour doesnโ€™t help you as much if you underexpose by using too short a shutter speed or too small a lens aperture. I tested the R6 in series of images underexposed by keeping ISO the same but decreasing the shutter speed then the aperture in one-stop increments. 

The underexposed images fell apart in quality much sooner, when underexposed more than 3 stops. Again, this is behaviour similar to what Iโ€™ve seen in Sonys and Nikons. For the best image quality I feel it is always a best practice to expose well at the camera. Donโ€™t count on saving images in post. 

An in-camera image fairly well exposed with an ETTR histogram.

TIP: Underexposing by using too short an exposure time is the major mistake astrophotographers make, who then wonder why their images are riddled with odd artifacts and patten noise. Always Expose to the Right (ETTR), even with ISO invariant cameras. The best way to avoid noise is to give your sensor more signal, by using longer exposures or wider apertures. Use settings that push the histogram to the right. 

LONG EXPOSURE NOISE REDUCTION

All cameras will exhibit thermal noise in long exposures, especially on warm nights. This form of noise peppers the shadows with hot pixels, often brightly coloured. 

This is not the same as the shot and read noise that adds graininess to high-ISO images and that noise reduction software can smooth out. This is a common misunderstanding, even among professional photographers who should know better! 

Thermal noise is more insidious and harder to eliminate in post without harming the image. However, Monika Deviat offers a clever method here at her website

The standard Canon LENR menu.

Long Exposure Noise Reduction (LENR) eliminates this thermal noise by taking a โ€œdark frameโ€ and subtracting it in-camera to yield a raw file free of hot pixels. 

And yes, LENR does apply to raw files, another fact even many professional photographers donโ€™t realize. It is High ISO Noise Reduction that applies only to JPGs, along with Color Space and Picture Styles.

Comparing a dark nightscape without and with LENR on a warm night. Hot pixels are mostly gone at right.

The LENR option on the R6 did eliminate most hot pixels, though sometimes still left, or added, a few. LENR is needed more on warm nights, and with longer exposures at higher ISOs. So the extent of thermal noise in any camera can vary a lot from shoot to shoot.

When LENR is active, the R6โ€™s rear screen lights up with โ€œBusy,โ€ which is annoyingly bright. To hide this display, the only option is to close the screen. 

As with the EOS Ra, and all mirrorless cameras, the R6 has no โ€œdark frame bufferโ€ that allows several exposures to be taken in quick succession even with LENR on. Canonโ€™s full-frame DSLRs have this little-known buffer that allows 3, 4, or 5 โ€œlight framesโ€ to be taken in a row before the LENR dark frame kicks in a locks up the camera on Busy. 

Comparing long exposure images with the lens cap on (dark frames), to show just thermal noise. The right edge of the frame is shown, blown up, to reveal the amp glow, which LENR removes.

With all Canon R cameras, and most other DSLRs, turning on LENR forces the camera to take a dark frame after every light frame, doubling the time it takes to finish every exposure. Thatโ€™s a price many photographers arenโ€™t willing to pay, but on warm nights it can be necessary, and a best practice, for the reward of cleaner images.

The standard Canon Sensor Cleaning menu.

TIP: If you find hot pixels are becoming more obvious over time, try this trick: turn on the Clean Manually routine for 30 seconds to a minute. In some cameras this can remap the hot pixels so the camera can better eliminate them.  

STAR QUALITY 

Using LENR with the R6 did not introduce any oddities such as oddly-coloured, green or wiped-out stars. Even without LENR I saw no evidence of green stars, a flaw that plagues some Sony cameras at all times, or Nikons when using LENR. 

Comparing the R6 for noise and star colours at typical deep-sky ISOs and exposure times.

Canons have always been known for their good star colours, and the R6 is no exception. According to DPReview the R6 has a low-pass anti-alias filter in front of its sensor. Cameras which lack such a sensor filter do produce sharper images, but stars that occupy only one or two pixels might not de-Bayer properly into the correct colours. Thatโ€™s not an issue with the R6.

I also saw no โ€œstar-eating,โ€ a flaw Nikons and Sonys have been accused of over the years, due to aggressive in-camera noise reduction even on raw files. Canons have always escaped charges of star-eating. 

VIGNETTING/SHADOWING

DSLRs are prone to vignetting along the top and bottom of the frame from shadowing by the upraised mirror and mirror box. Not having a mirror, and a sensor not deeply recessed in the body, largely eliminates this edge vignetting in mirrorless cameras. 

This illustrates the lack of edge shadows but magenta edge glows in a single Raw file boosted for contrast.

That is certainly true of the R6. Images boosted a lot in contrast, as we do with deep-sky photos, show not the slightest trace of vignetting along the top or bottom edges There were no odd clips or metal bits intruding into the light path, unlike in the Sony a7III I tested in 2018. 

The full frame of the R6 can be used without need for cropping or ad hoc edge brightening in post. Except โ€ฆ

EDGE ARTIFACTS/AMP GLOWS

The R6 did exhibit one serious and annoying flaw in long-exposure high-ISO images โ€“ a magenta glow along the edges, especially the right edge and lower right corner. 

Comparing a close-up of a nightscape, without and with LENR, to show the edge glow gone with LENR on.

Whether this is the true cause or not, it looks like โ€œamplifier glow,โ€ an effect caused by heat from circuitry illuminating the sensor with infra-red light. It shows itself when images are boosted in contrast and brightness in processing. Itโ€™s the sort of flaw revealed only when testing for the demands of astrophotography. It was present in images I took through a telescope, so it is not IR leakage from an auto-focus lens. 

I saw this type of amp glow with the Sony a7III, a flaw eventually eliminated in a firmware update that, I presume, turned off unneeded electronics in long exposures. 

Amp glow is something I have not seen in Canon cameras for many years. In a premium camera like the R6 it should not be there. Period. Canon needs to fix this with a firmware update.

UPDATE AUGUST 1, 2022: As of v1.6 of the R6 firmware, released in July 2022, the amp glow issue remains and has not been fixed. It may never be at this point.

It is the R6โ€™s only serious image flaw, but itโ€™s surprising to see it at all. Turning on LENR eliminates the amp glow, as it should, but using LENR is not always practical, such as in time-lapses and star trails.

For deep-sky photography high-ISO images are pushed to extremes of contrast, revealing any non-uniform illumination or colour. The usual practice of taking and applying calibration dark frames should also eliminate the amp glow. But Iโ€™d rather it not be there in the first place!

RED SENSITIVITY

The R6 I bought was a stock โ€œoff-the-shelfโ€ model. It is Canonโ€™s now-discontinued EOS Ra model that is (or was) โ€œfilter-modifiedโ€ to record a greater level of the deep red wavelength from red nebulas in the Milky Way. Compared to the Ra, the R6 did well, but could not record the depth of nebulosity the Ra can, to be expected for a stock camera. 

Comparing the stock R6 with the filter-modified Ra on Cygnus nebulosity.

In wide-field images of the Milky Way, the R6 picked up a respectable level of red nebulosity, especially when shooting through a broadband light pollution reduction filter, and with careful processing. 

Comparing the stock R6 with the filter-modified Ra on the Swan Nebula with a telescope with minimal processing to the Raw images.
Comparing the stock R6 with the filter-modified Ra on the Swan Nebula with a telescope with a dual narrowband filter and with colour correction applied to the single Raw images.

However, when going after faint nebulas through a telescope, even the use of a narrowband filter did not help bring out the target. Indeed, attempting to correct the extreme colour shift introduced by such a filter resulted in a muddy mess and accentuated edge glows with the R6, but worked well with the Ra. 

While the R6 could be modified by a third party, the edge amp glow might spoil images, as a filter modification can make a sensor even more sensitive to IR light, potentially flooding the image with unwanted glows. 

TIP: Buying a used Canon Ra (if you can find one) might be one choice for a filter-modified mirrorless camera, one much cheaper than a full frame cooled CMOS camera such as a ZWO ASI2400MC. Or Spencerโ€™s Camera sells modified versions of all the R series cameras with a choice of sensor filters. But I have not used any of their modded cameras.

RESOLUTION 

A concern of prospective buyers is whether the R6โ€™s relatively low 20-megapixel sensor will be sharp enough for their purposes. R6 images are 5472 by 3648 pixels, much less than the 8000+ pixel-wide images from high-resolution cameras like the Canon R5, Nikon Z7II or Sony a1.

Unless you sell your astrophotos as very large prints, Iโ€™d say donโ€™t worry. In comparisons with the 30-megapixel Ra I found it difficult to see a difference in resolution between the two cameras. Stars were nearly as well resolved in the R6, and only under the highest pixel-peeping magnification did stars look a bit more pixelated in the R6 than in the Ra. Faint stars were equally well recorded. 

Comparing resolution of the R6 vs. Ra with a blow-up of wide-field 85mm images
Comparing resolution of the R6 vs. Ra on blow-ups of the Andromeda Galaxy with a 76mm apo refractor. The R6 is more pixellated but it takes pixel peeping to see it!

The difference between 20 and 30 megapixels is not as great as you might think for arc-second-per-pixel plate scale. I think it would take going to the R5 with its 45 megapixel sensor to provide enough of a difference in resolution over the R6 to be obvious in nightscape scenes, or when shooting small, detailed deep-sky subjects such as globular clusters. 

If landscape or wildlife photography by day is your passion, with astrophotography a secondary purpose, then the more costly but highly regarded R5 might be the better choice. 

Super Resolution menu in Adobe Lightroom.

TIP: Adobe now offers (in Lightroom and in Camera Raw) a Super Resolution option, that users might think (judging by the rave reviews on-line) would be the answer to adding resolution to astro images from โ€œlow-resโ€ cameras like the R6. 

Comparing a normal R6 image with the same image upscaled with Super Resolution.

Sorry! In my tests on astrophotos Iโ€™ve found Super Resolution results unsatisfactory. Yes, stars were less pixelated, but they became oddly coloured in the AI-driven up-scaling. Green stars appeared! The sky background also became mottled and uneven. 

I would not count on such โ€œsmart upscalingโ€ options to add more pixels to astro-images from the R6. Then again, I donโ€™t think thereโ€™s a need to. 

RAW vs. cRAW

Canon now offers the option of shooting either RAW or cRAW files, the latter being the same megapixel count but compressed in file size by almost a factor of two. This allows shooting twice as many images before card space runs out, perhaps useful for shooting lots of time-lapses on extended trips away from a computer. 

The R6 Image Quality menu with the cRAW Option.
Comparing an R6 cRAW with a RAW image.

However, the compression is not lossless. In high-ISO test images purposely underexposed, then brightened in post, I could see a slight degradation in cRAW images โ€“ the noise background looked less uniform and exhibited a blocky look, like JPG artifacts. 

The R6’s dual SD card slots.

TIP: With two SD card slots in the R6 (the second card can be set to record either a backup of images on card one, or serve as an overflow card) and the economy of large SD cards, thereโ€™s not the need to conserve card space as there once was. I would suggest always shooting in the full RAW format. Why accept any compression and loss of image quality? 

BATTERY LIFE

The R6 uses a new version of Canonโ€™s standard LP-E6 battery, the LP-E6NH, that supports charging through the USB-C port and has a higher 2130mAh capacity than the 1800mAh LP-E6 batteries. However, the R6 is compatible with older batteries.

On warm nights, I found the R6 ran fine on one battery for the 3 to 4 hours needed to shoot a time-lapse sequence, with power to spare. However, as noted below, the lack of a top LCD screen means thereโ€™s no ongoing display of battery level, a deficiency for time-lapse and deep-sky work. 

For demanding applications, especially in winter, the R6 can be powered by an outboard USB power bank that has โ€œPower Deliveryโ€ capability. Thatโ€™s a handy feature. Thereโ€™s no need to install a dummy battery leading out to a specialized power source. 

The R6’s Connection menu with Airplane mode to turn off battery-eating WiFi and Bluetooth.

TIP: Putting the camera into Airplane mode (to turn off WiFi and Bluetooth), turning off the viewfinder, and either switching off or closing the rear screen all helps conserve power. The R6 does not have GPS built in. Tagging images with location data requires connecting to your phone.

VIDEO USE

A major selling point for me was the R6โ€™s low-light video capability. It replaces my Sony A7III, which had been my โ€œgo toโ€ camera for real-time 4K movies of auroras. 

As best I can tell (from the dimmer auroras Iโ€™ve shot to date), the R6 performs equally as well as the Sony. It is able to record good quality (i.e. acceptably noise-free) 4K movies at ISO 25,600 to ISO 51,200. While it can shoot at up to ISO 204,800, the excessive noise makes the top ISO an emergency-use only setting. 

The R6’s Movie size and quality options, with 4K and Full HD formats and frame rates.
Comparing the R6 on a dim aurora at various high ISO speeds. Narrated at the camera โ€” excuse the wind noise! Switch to HD mode for the best video playback quality. This was shot in 4K but WordPress plays back only in HD.

The R6 can shoot at a dragged shutter speed as slow as 1/8-second โ€“ good, though not as slow as the Sonyโ€™s 1/4-second slowest shutter speed in movie mode. That 1/8-second shutter speed and a fast f/1.4 to f/2 lens are the keys to shooting movies of the night sky. Only when auroras get shadow-casting bright can we shoot at the normal 1/30-second shutter speed and at lower ISOs.

As with Nikons (but not Sonys), the Canon R6 saves its movie settings separately from its still settings. When switching to Movie mode you donโ€™t have to re-adjust the ISO, for example, to set it higher than it might have been for stills, very handy for taking both stills and movies of an active aurora, where quick switching is often required. 

Unlike the R and Rp, the R6 captures 4K movies from the full width of the sensor, preserving the field of view of wide-angle lenses. This is excellent for aurora shooting. 

The R6’s Movie Cropping menu option
A 4K movie of the Moon in full-frame and copped-frame modes, narrated at the camera. Again, this was shot in 4K but WordPress plays back only in HD.
Comparing blow-ups of frame-grabbed stills from a full-frame 4K vs. Cropped frame 4K. The latter is less pixellated.

However, the R6 offers the option of a โ€œMovie Cropโ€ mode. Rather than taking the 4K movie downsampled from the entire sensor, this crop mode records from a central 1:1 sampled area of the sensor. That mode can be useful for high-magnification lunar and planetary imaging, for ensuring no loss of resolution. It worked well, producing videos with less pixelated fine details in test movies of the Moon. 

Though of course I have yet to test it on one, the R6 should be excellent for movies of total solar eclipses. It can shoot 4K up to 60 frames per second in both full frame and cropped frame. It cannot shoot 6K (buy the R3!) or 8K (buy the R5!). 

The R6’s Canon Log settings menu for video files.

Shooting in the R6โ€™s Canon cLog3 profile records internally in 10-bit, preserving more dynamic range in movies, up to 12 stops. During eclipses, that will be a benefit for recording totality, with the vast range of brightness in the Sunโ€™s corona. It should also aid in shooting auroras which can vary over a huge range in brightness. 

Grading a cLog format movie in Final Cut under Camera LUT.

TIP: Processing cLog movies, which look flat out of camera, requires applying a cLog3 Look Up Table, or LUT, to the movie clips in editing, a step called โ€œcolour grading.โ€ This is available from Canon, from third-party vendors or, as it was with my copy of Final Cut Pro, might be already installed in your video editing software. When shooting, turn on View Assist so the preview looks close to what the final graded movie will look like.

EXPOSURE TRACKING IN TIME-LAPSES

In one test, I shot a time-lapse from twilight to darkness with the R6 in Aperture Priority auto-exposure mode, of a fading display of noctilucent clouds. I just let the camera lengthen the shutter speed on its own. It tracked the darkening sky very well, right down to the camera’s maximum exposure time of 30 seconds, using a fish-eye lens at f/2.8. This demonstrated that the light meter in the R6 was sensitive enough to work well in dim light.

Other cameras I have used cannot do this. The meter fails at some point and the exposure stalls at 5 or 6 seconds long, resulting in most frames after that being underexposed. By contrast, the R6 showed excellent performance, negating the need for special bulb ramping intervalometers for some “holy grail” scenes. Here’s the resulting movie.

A time-lapse of 450 frames from 0.4 seconds to 30 seconds, with the R6 in Av mode. Set to 1080P for the best view!
A screenshot from LRTimelapse showing the smoothness of the exposure tracking (the blue line) through the sequence,

In addition, the R6’s exposure meter tracked the darkening sky superbly, with nary a flicker or variation. Again, few cameras can do this. Nikons have an Exposure Smoothing option in their Interval Timers which works well.

The R6 has no such option but doesn’t seem to need it. The exposure did fail at the very end, when the shutter reached its maximum of 30 seconds. If I had the camera on Auto ISO, it might have started to ramp up the ISO to compensate, a test I have yet to try. Even so, this is impressive time-lapse performance in auto-exposure.

MISSING FEATURES

The R6, like the low-end Rp, lacks a top LCD screen for display of camera settings and battery level. In its place we get a traditional Mode dial, which some daytime photographers will prefer. But for astrophotography, a backlit top LCD screen provides useful information during long exposures. 

The R6 top and back of camera view.

Without it, the R6 provides no indication of battery level while a shoot is in progress, for example, during a time-lapse. A top screen is also useful for checking ISO and other settings by looking down at the camera, as is usually the case when itโ€™s on a tripod or telescope. 

The lack of a top screen is an inconvenience for astrophotography. We are forced to rely on looking at the brighter rear screen for all information. It is a flip-out screen, so can be angled up for convenient viewing on a telescope.

The R6’s flip screen, similar to most other new Canon cameras.

The R6 has a remote shutter port for an external intervalometer, or control via a time-lapse motion controller. Thatโ€™s good! 

However, the port is Canonโ€™s low-grade 2.5mm jack. It works, and is a standard connector, but is not as sturdy as the three-pronged N3-style jack used on Canonโ€™s 5D and 6D DSLRs, and on the R3 and R5. Considering the cost of the R6, I would have expected a better, more durable port. The On/Off switch also seems a bit flimsy and easily breakable under hard use. 

The R6’s side ports, including the remote shutter/intervalometer port.

These deficiencies provide the impression of Canon unnecessarily โ€œcheaping outโ€ on the R6. You can forgive them with the Rp, but not with a semi-professional camera like the R6.

INTERVAL TIMER

Unlike the Canon R and Ra (which still mysteriously lack a built-in interval timer, despite firmware updates), the R6 has one in its firmware. Hurray! This can be used to set up a time-lapse sequence, but on exposures only up to the maximum of 30 seconds allowed by the cameraโ€™s shutter speed settings, true of most in-camera intervalometers. 

The Interval Timer menu page.

For 30-second exposures taken in succession as quickly as possible the interval on the R6 has to be set to 34 seconds. The reason is that the 30-second exposure is actually 32 seconds, true of all cameras. With the R6, having a minimum gap in time between shots requires an Interval not of 33 seconds as with some cameras, but 34 seconds. Until you realize this, setting the intervalometer correctly can be confusing. 

Like all Canon cameras, the R6 can be set to take only up to 99 frames, not 999. That seems a dumb deficiency. Almost all time-lapse sequences require at least 200 to 300 frames. What could it possibly take in the firmware to add an extra digit to the menu box? Itโ€™s there at in the Time-lapse Movie function that assembles a movie in camera, but not here where the camera shoots and saves individual frames. Itโ€™s another example where you just canโ€™t fathom Canonโ€™s software decisions.

Setting the Interval Timer for rapid sequence shots with a 30-second exposure.

TIP: If you want to shoot 100 or more frames, set the Number of Frames to 00, so it will shoot until you tell the camera to stop. But awkwardly, Canon says the way to stop an interval shoot is to turn off the camera! Thatโ€™s crude, as doing so can force you to refocus if you are using a Canon RF lens. Switching the Mode dial to Bulb will stop an interval shoot, an undocumented feature. 

BULB TIMER

As with most recent Canon DSLRs and DSLMs, the menu also includes a Bulb Timer. This allows setting an exposure of any length (many minutes or hours) when the camera is in Bulb mode. This is handy for single long shots at night. 

The Bulb Timer menu page. Bulb Timer only becomes an active choice when the camera is on Bulb.

However, it cannot be used in conjunction with the Interval Timer to program a series of multi-minute exposures, a pity. Instead, a separate outboard intervalometer has to be used for taking an automatic set of any exposures longer than 30 seconds, true of all Canons. 

In Bulb and Bulb Timer mode, the R6โ€™s rear screen lights up with a bright Timer readout. While the information is useful, the display is too bright at night and cannot be dimmed, nor turned red for night use, exactly when you are likely to use Bulb. The power-saving Eco mode has no effect on this display, precisely when you would want it to dim or turn off displays to prolong battery life, another odd deficiency in Canonโ€™s firmware. 

The Bulb Timer screen active during a Bulb exposure. At night it is bright!

The Timer display can only be turned off by closing the flip-out screen, but now the viewfinder activates with the same display. Either way, a display is on draining power during long exposures. And the Timer readout lacks any indication of battery level, a vital piece of information during long shoots. The Canon R, R3 and R5, with their top LCD screens, do not have this annoying โ€œfeature.โ€ 

TIP: End a Bulb Timer shoot prematurely by hitting the Shutter button. That feature is documented. 

IN-CAMERA IMAGE STACKING

The R6 offers a menu option present on many recent Canon cameras: Multiple Exposure. The camera can take and internally stack up to 9 images, stacking them by using either Average (best for reducing noise) or Bright mode (best for star trails). An Additive mode also works for star trails, but stacking 9 images requires reducing the exposure of each image by 3 stops, say from ISO 1600 to ISO 200, as I did in the example below. 

The Multiple Exposure menu page.

The result of the internal stacking is a raw file, with the option of also saving the component raws. While the options work very well, in all the cameras Iโ€™ve owned that offer such functions, Iโ€™ve never used them. I prefer to do any stacking needed later at the computer. 

Comparing a single image with a stack of 9 exposures with 3 in-camera stacking methods.

TIP: The in-camera image stacking options are good for beginners wanting to get advanced stacking results with a minimum of processing fuss later. Use Average to stack ground images for smoother noise. Use Bright for stacking sky images for star trails. Activate one of those modes, then control the camera with a separate intervalometer to automatically shoot and internally stack several multi-minute exposures. 

SHUTTER OPERATION

Being a mirrorless camera, there is no reflex mirror to introduce vibration, and so no need for a mirror lockup function. The shutter can operate purely mechanically, with physical metal curtains opening and closing to start and end the exposure. 

However, the default โ€œout of the boxโ€ setting is Electronic First Curtain, where the actual exposure, even when on Bulb, is initiated electronically, but ended by the mechanical shutter. Thatโ€™s good for reducing vibration, perhaps when shooting the Moon or planets through a telescope at high magnification. 

R6 Shutter Mode options.

In Mechanical, the physical curtains both start and end the exposure. Itโ€™s the mode I usually prefer, as I like to hear the reassuring click of the shutter opening. Iโ€™ve never found shutter vibration a problem when shooting deep sky images on a telescope mount of any quality. 

In Mechanical mode the shutter can fire at up to 12 frames a second, or up to 20 frames a second in Electronic mode where both the start and end of the exposure happen without the mechanical shutter. That makes for very quiet operation, good for weddings and golf tournaments! 

Electronic Shutter Mode is for fastest burst rates but has limitations.

Being vibration free, Electronic shutter might be great during total solar eclipses for rapid-fire bursts at second and third contacts when shooting through telescopes. Maximum exposure time is 1/2 second in this mode, more than long enough for capturing fleeting diamond rings.

Longer exposures needed for the corona will require Mechanical or Electronic First Curtain shutter. Combinations of shutter modes, drive rates (single or continuous), and exposure bracketing can all be programmed into the three Custom Function settings (C1, C2 and C3) on the Mode dial, for quick switching at an eclipse. It might not be until April 8, 2024 until I have a chance to test these features. And by then the R6 Mark II will be out! 

TIP: While the R6โ€™s manual doesnโ€™t state it, some reviews mention (including at DPReview) that when the shutter is in fully Electronic mode the R6โ€™s image quality drops from 14-bit to 12-bit, true of most other mirrorless cameras. This reduces dynamic range. I would suggest not using Electronic shutter for most astrophotography, even for exposures under 1/2 second. For longer exposures, itโ€™s a moot point as it cannot be used. 

The menu option that fouls up all astrophotographers using an R-series camera.

TIP: The R6 has the same odd menu item that befuddles many a new R-series owner, found on Camera Settings: Page 4. โ€œRelease Shutter w/o Lensโ€ defaults to OFF, which means the camera will not work if it is attached to a manual lens or telescope it cannot connect to electronically. Turn it ON and all will be solved. This is a troublesome menu option that Canon should eliminate or default to ON. 

OTHER MENU FEATURES

The rear screen is fully touch sensitive, allowing all settings to be changed on-screen if desired, as well as by scrolling with the joystick and scroll wheels. I find going back to an older camera without a touchscreen annoying โ€“ I keep tapping the screen expecting it to do something! 

The Multi-Function Button brings up an array of 5 settings to adjust. This is ISO.

The little Multi-Function (M-Fn) button is a worth getting used to, as it allows quick access to a choice of five important functions such as ISO, drive mode and exposure compensation. However, the ISO, aperture and shutter speed are all changeable by the three scroll wheels. 

The Q button brings up the Quick Menu for displaying and adjusting key functions.

Thereโ€™s also the Quick menu activated by the Q button. While the content of the Quick menu screen canโ€™t be edited, it does contain a good array of useful functions, adjustable with a few taps. 

Under Custom settings, the Dials and Buttons can be re-assigned to other functions.

Unlike Sonys, the R6 has no dedicated Custom buttons per se. However, it does offer a good degree of customization of its buttons, by allowing users to re-assign them to other functions they might find more useful than the defaults. For example โ€ฆ.

This shows the AF Point button being re-assigned to the Maximize Screen Brightness (Temporary) command.
  • Iโ€™ve taken the AF Point button and assigned it to the Maximize Screen Brightness function, to temporarily boost the rear screen to full brightness for ease of framing. 
  • The AE Lock button I assigned to switch the Focus Peaking indicators on and off, to aid manual focusing when needed. 
  • The Depth of Field Preview button I assigned to switching between the rear screen and viewfinder, through that switch does happen automatically as you put your eye to the viewfinder.
  • The Set button I assigned to turning off the Rear Display, though that doesnโ€™t have any effect when the Bulb Timer readout is running, a nuisance. 

While the physical buttons are not illuminated, having a touch screen makes it less necessary to access buttons in the dark. Itโ€™s a pity the conveniently positioned but mostly unused Rate button canโ€™t be re-programmed to more useful functions. Itโ€™s a waste of a button. 

Set up the Screen Info as you like it by turning on and off screen pages and deciding what each should show.

TIP: The shooting screens, accessed by the Info button (one you do need to find in the dark!), can be customized to show a little, a lot, or no information, as you prefer. Take the time to set them up to show just the information you need over a minimum of screen pages. 

LENS AND FILTER COMPATIBILITY

The new wider RF mount accepts only Canon and third-party RF lenses. However, all Canon and third-party EF mount lenses (those made for DSLRs) will fit on RF-mount bodies with the aid of the $100 Canon EF-to-RF lens adapter. 

The Canon ER-to-RF lens adapter will be needed to attach R cameras to most telescope camera adapters and Canon T-rings made for older DSLR cameras.

This adapter will be necessary to attach any Canon R camera to a telescope equipped with a standard Canon T-ring. Thatโ€™s especially true for telescopes with field flatterers where maintaining the standard 55mm distance between the flattener and sensor is critical for optimum optical performance. 

The shallower โ€œflange distanceโ€ between lens and sensor in all mirrorless cameras means an additional adapter is needed not just for the mechanical connection to the new style of lens mount, but also for the correct scope-to-sensor spacing. 

The extra spacing provided by a mirrorless camera has the benefit of allowing a filter drawer to be inserted into the light path. Canon offers a $300 lens adapter with slide-in filters, though the choice of filters useful for astronomy that fit Canonโ€™s adapter is limited. AstroHutech offers a few IDAS nebula filters.

Clip-in filters made for the EOS R, such as those offered by Astronomik, will also fit the R6. Though, again, most narrowband filters will not work well with an unmodified camera.

The AstroHutech adapter allows inserting filters into the light path on telescopes.

TIP: Alternatively, AstroHutech also offers its own lens adapter/filter drawer that goes from a Canon EF mount to the RF mount, and accepts standard 52mm or 48mm filters. It is a great way to add interchangeable filters to any telescope when using an R-series camera, while maintaining the correct back-focus spacing. I use an AstroHutech drawer with my Ra, where the modified camera works very well with narrowband filters. Using such filters with a stock R6 wonโ€™t be as worthwhile, as I showed above. 

A trio of Canon RF zooms โ€” all superb but quite costly.

As of this writing, the selection of third-party lenses for the Canon RF mount is limited, as neither Canon or Nikon have โ€œopened upโ€ their system to other lens makers, unlike Sony with their E-mount system. For example, we have yet to see much-anticipated RF-mount lenses from Sigma, Tamron and Tokina. 

A trio of third party RF lenses โ€” L to R: the TTArtisan 7.5mm f/2 and 11mm f/2.8 fish-eyes and the Samyang/Rokinon AF 85mm f/1.4.

Samyang offers 14mm and 85mm auto-focus RF lenses, but now only under their Rokinon branding. I tested the Samyang RF 85mm f/1.4 here at AstroGearToday

The few third-party lenses that are available, from TTArtisan, Venus Optics and other boutique Chinese lens companies, are usually manual focus lenses with reverse-engineered RF mounts offering no electrical contact with the camera. Some of these wide-angle lenses are quite good and affordable. (I tested the TTArtisan 11mm fish-eye here.)

Until other lens makers are โ€œallowed in,โ€ if you want lenses with auto-focus and camera metadata connections, you almost have to buy Canon. Their RF lenses are superb, surpassing the quality of their older EF-mount equivalents. But they are costly. I sold off a lot of my older lenses and cameras to help pay for the new Canon glass! 

I also have reviews of the superb Canon RF 15-35mm f/2.8, as well as the unique Canon RF 28-70mm f/2 and popular Canon RF 70-200mm f/2.8 lenses (a trio making up the  โ€œholy trinityโ€ of zooms) at AstroGearToday.com.

CONTROL COMPATIBILITY 

Astrophotographers often like to operate their cameras at the telescope using computers running specialized control software. I tested the R6 with two popular Windows programs for controlling DSLR and now mirrorless cameras, BackyardEOS (v3.2.2) and AstroPhotographyTool (v3.88). Both recognized and connected to the R6 via its USB port. 

Both programs recognized the Canon R6.

Another popular option is the ASIair WiFi controller from ZWO. It controls cameras via one of the ASIairโ€™s USB ports, and not (confusingly) through the Airโ€™s remote shutter jack marked DSLR. Under version 1.7 of its mobile app, the ASIair now controls Canon R cameras and connected to the R6 just fine, allowing images to be saved both to the camera and to the Airโ€™s own MicroSD card. 

With an update in 2021, the ZWO ASIair now operates Canon R-series cameras.

The ASIair is an excellent solution for both camera control and autoguiding, with operation via a mobile device that is easier to use and power in the field than a laptop. Iโ€™ve not tried other hardware and software controllers with the R6. 

TIP: While the R6, like many Canon cameras, can be controlled remotely with a smartphone via the CanonConnect mobile app, the connection process is complex and the connection can be unreliable. The Canon app offers no redeeming features for astrophotography, and maintaining the connection via WiFi or Bluetooth consumes battery power. 

A dim red and green aurora from Dinosaur Provincial Park, Alberta, on August 29/30, 2021. This is a stack of 4 exposures for the ground to smooth noise and one exposure for the sky, all 30 seconds at f/2.8 with the Canon 15-35mm RF lens at 25mm and the Canon R6 at ISO 4000.

SUGGESTIONS TO CANON

To summarize, in firmware updates, Canon should:

  • Fix the low-level amp glow. No camera should have amp glow. 
  • Allow either dimming the Timer readout, turning it red, or just turning it off!
  • Add a battery display to the Timer readout. 
  • Expand the Interval Timer to allow up to 999 frames, as in the Time-Lapse Movie. 
  • Allow the Rate button to be re-assigned to more functions.
  • Default the Release Shutter w/o Lens function to ON.
  • Revise the manual to correctly describe how to stop an Interval Timer shoot.
  • Allow programming multiple long exposures by combining Interval and Bulb Timer, or by expanding the shutter speed range to longer than 30 seconds, as some Nikons can do.
The Zodiacal Light in the dawn sky, September 14, 2021, from home in Alberta, with the winter sky rising. This is a stack of 4 x 30-second exposures for the ground to smooth noise, and a single 30-second exposure for the sky, all with the TTArtisan 7.5mm fish-eye lens at f/2 and on the Canon R6 at ISO 1600.

CONCLUSION

The extended red sensitivity of the Canon EOS Ra makes it better suited for deep-sky imaging. But with it now out of production (Canon traditionally never kept its astronomical โ€œaโ€ cameras in production for more than two years), I think the R6 is now Canonโ€™s best camera (mirrorless or DSLR) for all types of astrophotography, both stills and movies. 

However, I cannot say how well it will work when filter-modified by a third-party. But such a modification is necessary only for recording red nebulas in the Milky Way. It is not needed for other celestial targets and forms of astrophotography. 

A composite showing about three dozen Perseid meteors accumulated over 3 hours of time, compressed into one image showing the radiant point of the meteor shower in Perseus. All frames were with the Canon R6 at ISO 6400 and with the TTArtisan 11mm fish-eye lens at f/2.8.

The low noise and ISO invariant sensor of the R6 makes it superb for nightscapes, apart from the nagging amp glow. That glow will also add an annoying edge gradient to deep-sky images, best dealt with when shooting by the use of LENR or dark frames. 

As the image of the Andromeda Galaxy, M31, at the top of the blog attests, with careful processing it is certainly possible to get fine deep-sky images with the R6. 

For low-light movies the R6 is Canonโ€™s answer to the Sony alphas. No other Canon camera can do night sky movies as well as the R6. For me, it was the prime feature that made the R6 the camera of choice to complement the Ra. 

โ€” Alan, September 22, 2021 / ยฉ 2021 Alan Dyer / AmazingSky.com  

Following the Evening Star


Selfie with Binoculars Looking at Moon (Feb 27, 2020)It’s been a marvelous few months following Venus rise and fall across the evening sky, in its best show in eight years.

Venus is now gone from our western sky, but since late 2019 until late May 2020 it had dominated the sky as a brilliant evening star.

Here’s a gallery of Venus portraits I shot during its wonderful show these last few months.


The show began in November 2019 when rising Venus met declining Jupiter on November 23 for a fine conjunction of the two brightest planets in the evening twilight.

Venus and Jupiter over the Rockies
The conjunction of Venus and Jupiter of November 23, 2019, as seen over the foothills and front ranges of the Rocky Mountains in southwest Alberta. I shot this from the Rothney Astrophysical Observatory, prior to their monthly Open House event that night with about 400 in attendance. But at this time it was just me and one other ardent photographer present to shoot this scene. This is an HDR blend (stacked using Adobe Camera Raw) of 5 exposures at 2/3-stop intervals, with the Rokinon 85mm lens at f/4 on the red-sensitive Canon EOS Ra camera at ISO 100.


A week later I captured the line of the then three evening planets and the Moon across the southwest, defining the path of the ecliptic across the evening sky.

Moon and Three Planets Line-Up
The waxing crescent Moon and three planets in a line across the southwestern evening sky on Nov. 30, 2019, a chilly and frosty night. Saturn is below and to the right of the Moon, Venus is brightest at centre, while Jupiter is to the lower right of Venus just above the horizon. Those two planets were in conjunction a week earlier. The line of Moon and planets visibly defines the ecliptic low across the late autumn evening sky. This is from latitide 51ยฐ N. I shot this from the viewpoint at Blackfoot Crossing overlooking the Bow River in Alberta.


A week after that I took the opportunity to shoot some selfies of me with binoculars looking at Venus, as it met Saturn in a wide conjunction, with Venus then still low in the southwest. It was just beginning its climb up into the western sky.

Observing Venus and Saturn (Dec 8, 2019)
A selfie of me observing the grouping of Venus and Saturn in the evening twilight on Dec 8, 2019, using binoculars. They were closest to each other two nights later.


A month later in mid-winter, Venus was still rather low but brilliant even in a hazy moonlit sky, as I posed for another selfie, this time with a small telescope. These images are always useful for illustrations in books and magazines. And blogs!

Observing Venus in Clouds
A selfie of me observing Venus in clouds and in the moonlight. I am using the Explore Scientific 80mm refractor on the Twilight Nano alt-az mount. This was January 9, 2020.


By the end of February Venus had climbed high into the west, and was appearing monthly near the waxing crescent Moon. This is another binocular selfie from February 27.

Selfie with Binoculars Looking at Moon (Feb 27, 2020)
A selfie looking at the waxing crescent Moon near Venus on Feb 27, 2020, using the Celestron SkyMaster 15×70 Pro binoculars on the Sky-Watcher AZ5 mount for a steady view. This is a single shot with the Nikon D750 and Sigma 24mm lens, using the flash on the camera.


In March I visited Churchill, Manitoba just as the lockdown and travel restrictions were coming into effect. But our lone and last tour group at the Churchill Northern Studies Centre saw some fine auroras, as here on this evening with the Northern Lights appearing even in the twilight. And what’s that bright star? Venus, of course!

Aurora in Twilight at Churchill Northern Studies Centre
The Northern Lights in the evening twilight on March 18, 2020, as the aurora appeared in the early evening sky. Orion is at far left in this panorama, with Cassiopeia at top centre. Part of the Big Dipper is at far right. The bright object over the Centre is Venus, with the Pleiades above. This is a panorama of 8 segments with the Venus Optics 15mm lens at f/2 and Sony a7III at ISO 800 for 1.6 seconds each. Stitched with Photoshop.


Upon my return home to Alberta, I was able to shoot more panoramas on the prairies of the wonderful early spring sky with Orion setting into the twilight and Venus in Taurus shining below the iconic Pleiades star cluster.

Panorama of  Venus and the Winter Stars (March 25, 2020)
This is a panorama of the evening sky on March 25, 2020, with brilliant Venus high in the west at centre just after the date (March 24) of its greatest elongation in the evening sky for 2020. It appears here about as high as it can get with the ecliptic tipped up to a high angle in spring. To the left is Orion and the winter stars in the twilight, including Sirius at far left. Just above the horizon right of centre in the bright twilight is the day-old thin crescent Moon about to set. Above Venus are the Pleiades and Hyades star clusters. This is a panorama of 5 segments with the Nikon D750 and 24mm Sigma lens, stitched with PTGui. Each segment was 8 seconds at ISO 400 and f/2.8.


March 26 was a superb night for catching Venus now at its highest and almost at its brightest at this appearance, as the waxing Moon appeared below it.


The highlight of the spring Venus season was its close approach to the Pleiades, which it passes only every 8 years. Here I am viewing the conjunction two days before the closest approach, with Orion over my shoulder.

Viewing Venus & Pleiades with Big Binoculars
A selfie of me viewing the close approach of Venus to the Pleiades star cluster on April 1, 2020, using big 15×70 Celestron SkyMaster Pro binoculars mounted on a Canadian-built Starlight Innovations binocular mount, a parallelogram-style mount. Orion is over my left shoulder; the Hyades is at centre above the mount. The waxing gibbous Moon provided the illumination. This is a stack of 4 images for the ground to smooth noise and 1 image for the sky to minimize trailing, all 13 seconds at f/5.6 with the Sigma 24mm lens and Nikon D750 at ISO 1600. Topaz Sharpen AI and DeNoise AI applied.


The night of closest approach, April 3, was cloudy, but here is a consolation closeup taken the next night with brilliant Venus departing the Seven Sisters.

Venus and the Pleiades - Close-Up (April 4, 2020)
Venus above the Pleiades star cluster, M45, on April 4, 2020, in the twilight and moonlight. Light from the gibbous Moon illuminated the sky, so no long exposure would reveal much detail in and around the Pleiades. Venus passes close to the Pleiades only every 8 years. Some light cloud this night added the glow. This is a stack of multiple exposures of varying lengths: 2 minutes, 30 seconds, 10 seconds and 2 seconds, blended with masks to prevent Venus from being too blown out while still recording the stars. All were with the SharpStar 140mm PH apo refractor with the 0.73x flattener/reducer for f/4.8 and at ISO 400 with the Canon EOS Ra.


Later in April Venus reached its greatest brilliancy, at magnitude -4.7, the date when the size of is disk, phase, and proximity to Earth converge to make Venus as bright as possible. On this night I shot the Moon, then 30ยฐ away from Venus and the planet with the same gear to show their relative sizes and similar crescent phase this night. The caption provides more details.

Moon and Venus Crescents Compared
A collage of two images of the Moon and Venus taken minutes apart on April 28, 2020, to show the similarity in their phases this night, April 28, 2020. Both images were shot with the same focal length and camera and so are identical in image scale, to compare their apparent sizes. I have not enlarged Venus, but I have put a frame around it to emphasize that its image has been layered in as a composite. The Moon was a 5.6-day-old waxing crescent this night, 32% illuminated. Venus was at its greatest brilliancy, or Greatest Illuminated Extent, with a disk 38 arc seconds across and 27% illuminated, so slightly less. Taken with the 130mm Astro-Physics refractor with a 2X Barlow lens for an effective focal length of 1600mm and with the Canon 60Da APS-sensor camera. The Moon image is the full frame of the sensor, uncropped. Both images are single short exposures at ISO 100.


A week later, with Venus just past its point of greatest brilliancy, I shot the planet by daylight in the early evening sky, using a telescope to zoom into the planet to show its waning crescent phase. By this time the phase was obvious in binoculars.

Venus in the Day Sky
Venus in the daytime sky and through some thin clouds, on May 5, 2020, with Venus at a very high apparition. This was at about 7 pm with the Sun still well up in the early evening, to show how well Venus can be seen in the daytime sky when it is at a wider angle from the Sun; and indeed is often the best time to view it as the planetโ€™s brilliance is muted. This is a single 1/400-second exposure at ISO 100 with the Canon 60Da through the Astro-Physics 130mm refractor and 2X Barlow for f/12 and 1600mm focal length.


But Venus was now dropping rapidly from sight. By May 23, it was low in the twilight and below Mercury, then at its best for 2020 for an evening appearance from my latitude. Note the thin Moon below the planets. This was a superb sight for binoculars.

Thin Moon below Venus and Mercury
On May 23, 2020, the very thin crescent Moon (then 34 hours old) shines below bright Venus (10 days before its inferior conjunction with the Sun) and above it dimmer Mercury , then 10 days before its greatest elongation from the Sun in the evening sky. All were beautifully visible to the naked eye and a great sight in binoculars, looking very much like this scene captured with a 135mm telephoto lens. Venus was magnitude -4.4, Mercury was -0.7. This is a single shot at f/2.8 and 1/ 5 second at ISO 100 with the Canon EOS Ra which does bring out the sunset reds well.


By May 29, Venus was now tough to pick out of the evening sky, and a challenge to shoot even by day, as it then stood only 8ยฐ away from the Sun. What was once obvious to the naked eye now took a computerized telescope to pick out of the noon-day blue sky. A telescope showed the now razor-thin crescent as Venus approached its June 3 “inferior conjunction” โ€” its passage between Earth and the Sun.

Venus Near Inferior Conjunction (May 29, 2020)
Venus as a razor-thin crescent and only 8ยฐ east of the Sun on May 29, 2020, five days before its June 3 inferior conjunction. The crescent is extending a little beyond 180ยฐ here due to scattering in the Venusian clouds. The disk was 57 arc seconds across and 0.9% illuminated. The magnitude was -3.9. This was at midday, shot with the 130mm Astro-Physics f/6 refractor with a 2X Barlow and the Canon 60Da camera, but the frame cropped further in processing. This is a single 1/1250th second exposure at ISO 100, the sharpest of 70 still frames taken.


I shot and narrated video footage of the thin crescent Venus, my parting shots of Venus for its evening appearance in 2020.

But in June, post inferior conjunction, it will rise very quickly into our morning sky, providing a mirror-image repeat performance as a morning star for the rest of 2020.

Venus Near Inferior Conjunction from Alan Dyer on Vimeo.


I wish you all the best and a safe and healthy time in 2020. Take some solace in what the sky can show us and in the beauty of the night.

Clear skies!

โ€” Alan, May 31, 2020 / AmazingSky.comย 

 

Shooting with Canon’s EOS Ra Camera


IC 1805 in Cassiopeia (Traveler and EOS Ra)

I had the chance to test out an early sample of Canon’s new EOS Ra camera designed for deep-sky photography.ย 

Once every 7 years astrophotographers have reason to celebrate when Canon introduces one of their “a” cameras, astronomical variants optimized for deep-sky objects, notably red nebulas.

In 2005 Canon introduced the ground-breaking 8-megapixel 20Da, the first DLSR to feature Live View for focusing. Seven years later, in 2012, Canon released the 18-megapixel 60Da, a camera I still use and love.

Both cameras were cropped-frame DSLRs.

Now in 2019, seven years after the 60Da, we have the newly-released EOS Ra, the astrophoto version of the 30-megapixel EOS R released in late 2018. The EOS R is a full-frame mirrorless camera with a sensor similar to what’s in Canon’s 5D MkIV DSLR.

Here, I present a selection of sample images taken with the new EOS Ra.

Details on its performance is at my “first-look” review at Sky and Telescope magazine’s website.

IC 1805 in Cassiopeia (Traveler and EOS Ra)
The large emission nebula IC 1805 in Cassiopeia, aka the Heart Nebula. The round nebula at top right is NGC 896. The large loose star cluster at centre is Mel 15; the star cluster at left is NGC 1027. The small cluster below NGC 896 is Tombaugh 4. This is a stack of 8 x 6-minute exposures with the Canon EOS Ra mirrorless camera at ISO 1600 through the Astro-Physics Traveler apo refractor at f/6 with the Hotech field flattener. Stacked, aligned and processed in Photoshop.

Both versions of the EOS R have identical functions and menus.

The big difference is that the EOS Ra, as did Canon’s earlier “a” models, has a factory-installed filter in front of the sensor that transmits more of the deep red “hydrogen-alpha” wavelength emitted by glowing nebulas.

Normal cameras suppress much of this deep-red light as a by-product of their filters cutting out the infra-red light that digital sensors are very sensitive to, but that would not focus well.

NGC 7000 North America Nebula (105mm Apo & Canon EOS Ra)
The North America Nebula, NGC 7000, in Cygnus, taken with the new Canon EOS Ra factory-modified โ€œastronomicalโ€ version of the Canon EOS R mirrorless camera. This is a stack of 4 x 6-minute exposures, with LENR on and at ISO 1600, through the Astro-Physics Traveler 105mm f/6 apo refractor with the Hutech field flattener.

I was sent an early sample of the EOS Ra, and earlier this autumn also had a sample of the stock EOS R.

Both were sent for testing so I could prepare a test report for Sky and Telescope magazine. The full test report will appear in an upcoming issue.

IC 1396 in Cepheus (Traveler and EOS Ra)
The large emission nebula IC 1396 in Cepheus with the orange โ€œGarnet Starโ€ at top, and the Elephant Trunk Nebula, van den Bergh 142, at bottom as a dark lane protruding into the emission nebula. This is a stack of 5 x 6-minute exposures with the Canon EOS Ra mirrorless camera at ISO 1600 through the Astro-Physics Traveler apo refractor at f/6 with the Hotech field flattener. Stacked, aligned and processed in Photoshop.

But my “first-look” review can be found here on the Sky and Telescope website.

Please click thru for comments on:

โ€ข How the Ra compares to previous “a” models and third-party filter-modified cameras

โ€ข How the Ra works for normal daylight photography

โ€ข Noise levels compared to other cameras

โ€ข Features unique to the EOS Ra, such as 30x Live View focusing

Messier 52 and the Bubble Nebula (Traveler and EOS Ra)
Messier 52 open cluster, at left, and the Bubble Nebula, NGC 7635 below and to the right of it, at centre, plus the small red nebula NGC 7538 at right. The open cluster at lower right is NGC 7510. All in Cassiopeia. This is a stack of 8 x 6-minute exposures at ISO 1600 with the Canon EOS Ra camera and Astro-Physics Traveler apo refractor at f/6 with the Hotech field flattener. No LENR dark frame subtraction employed as the temperature was -15ยฐ C.


UPDATE โ€” November 25, 2019

As part of further testing I shot the Heart and Soul Nebulas in Cassiopeia through my little Borg 77mm f/4 astrograph with both the EOS Ra and my filter-modified 5D MkII (modified years ago by AstroHutech) to compare which pulled in more nebulosity. It looked like a draw.

Both images are single 8-minute exposures, taken minutes apart and developed identically in Adobe Camera Raw, but adjusted for colour balance to equally neutralize the sky background. The histograms look similar. Even so, the Ra looks a little redder overall. But keep in mind a sky or nebula can be made to appear any shade of red you like in processing.

The question is which camera shows more faint nebulosity?

The modified 5D MkII has always been my favourite camera for this type of astrophotography, picking up more nebulosity than other “a” models I’ve tested, including the Nikon D810a.

But in this case, I’d say the EOS Ra is performing as well as, if not better than the 5D MkII. How well any third-party modified camera you buy now performs will depend which, if any, filter the modifier installs in front of the sensor. So your mileage will vary.

EOS Ra and 5D MkII Comparison


For most of my other testing I shot through my much-prized Astro-Physics Traveler, a 105mm aperture f/6 apochromatic refractor on the Astro-Physics Mach1 mount.

To connect the EOS Ra (with its new RF lens mount) to my existing telescope-to-camera adapter and field flattener lens I used one of Canon’s EF-EOS R lens adapters.

EOS Ra on Scope

EOS Ra on Scope CU

The bottom line is that the EOS Ra works great!

It performs very well on H-alpha-rich nebulas and has very low noise. It will be well-suited to not only deep-sky photography but also to wide-field nightscape and time-lapse photography, perhaps as Canon’s best camera yet for those applications.

EOS Ra Front View-Face On

WHAT ABOUT THE PRICE?

The EOS Ra will sell for $2,500 US, a $700 premium over the cost of the stock EOS R. Some complain. Of course, if you don’t like it, you don’t have to buy it. This is not an upgrade being forced upon you.

As I look at it, it is all relative. When Nikon’s astronomy DSLR, the 36 Mp D810a, came out in 2015 it sold for $3,800 US, $1,300 more than the EOS Ra. It was, and remains a fine camera, if you can find one. It is discontinued.

A 36 Mp cooled and dedicated CMOS astro camera, the QHY367, with the same chip as the D810a, goes for $4,400, $1,900 more than the Ra. Yes, it will produce better images I’m sure than the EOS Ra, but deep-sky imaging is all it can do. At a cost, in dollars and ease of use.

And yes, buying a stock EOS R and having it modified by a third party costs less, and you’ll certainly get a good camera, for $300 to $400 less than an Ra.ย But …

โ€ข The EOS Ra has a factory adjusted white balance for ease of “normal” use โ€” no need to buy correction filters. So there’s a $$ saving there, even if you can find clip-in correction filters for the EOS R โ€” you can’t.

โ€ข And the Ra retains the sensor dust cleaning function. Camera modifier companies remove it or charge more to reinstall it.

โ€ข And the 30x live view magnification is very nice.

โ€ข The EOS Ra also carries a full factory warranty.

Do I wish the EOS Ra had some other key features? Sure. A mode to turn all menus red would be nice. As would an intervalometer built-in, one that works with the Bulb Timer to allow sequences of programmed multi-minute exposures. Both could be added in with a firmware update.

And providing a basic EF-EOS R lens adapter in the price would be a welcome plus, as one is essential to use the EOS Ra on a telescope.

Thatโ€™s my take on it. Iโ€™ll be buying one. But then again I bought the 20Da, twice!, and the 60Da, and I hate to think what I paid for those much less capable cameras.

Canon EOS Ra and 15-35mm

BONUS TEST โ€” The RF 15-35mm L Lens

Canon is also releasing an impressive series of top-class RF lenses for their R mirrorless cameras. The image below is an example astrophoto with the new RF 15-35mm f/2.8 L zoom lens, an ideal combination of focal lengths and speed for nightscape shooting.

Orion and Winter Stars Rising
Orion and the winter stars rising on a late October night, with Sirius just clearing the horizon at centre bottom, Capella and the Pleiades are at top. M44 cluster is at far left. Taken with the Canon 15-35mm RF lens at 15mm and f/2.8 and the EOS Ra camera at ISO 800 as part of testing. A stack of 4 x 2-minute exposures on the Star Adventurer tracker.

Below is a further set of stacked and processed images with the RF 15-35mm L lens, taken in quick succession, at 15mm, 24mm, and 35mm focal lengths, all shot wide open at f/2.8. The EOS Ra was on the Star Adventurer tracker (as below) to follow the stars.

EOS Ra on Star Adventurer

Click or tap on the images below to view a full-resolution version for closer inspection.

Autumn Milky Way (15-35mm RF at 15mm + EOS Ra).jpg
15mm โ€” Northern autumn Milky Way with RF 15-35mm at f/2.8 and at 15mm focal length. Taken with the EOS Ra at ISO 800 for a stack of 4 x 2-minute exposures.

Autumn Milky Way (15-35mm RF at 24mm + EOS Ra).jpg
24mm โ€” Northern autumn Milky Way with RF 15-35mm at f/2.8 and at 24mm focal length. Taken with the EOS Ra at ISO 800 for a stack of 2 x 2-minute exposures.

Autumn Milky Way (15-35mm RF at 35mm + EOS Ra).jpg
35mm โ€” Northern autumn Milky Way with RF 15-35mm at f/2.8 and at 35mm focal length. Taken with the EOS Ra at ISO 800 for a stack of 2 x 2-minute exposures.

The RF 15-35mm lens performs extremely well at 15mm exhibiting very little off-axis aberrations at the corners.

Off-axis aberrations do increase at the longer focal lengths but are still very well controlled, and are much less than I’ve seen on my older zoom and prime lenses in this focal length range.

The RF 15-35mm is a great complement to the EOS Ra for wide-field Milky Way images.

I was impressed with the new EOS Ra. It performs superbly for astrophotography.

Again, click through to Sky and Telescope for “first look” details on the test results.

โ€” Alan, November 6, 2019 / UPDATED Nov 25, 2019 / ยฉ 2019 AmazingSky.comย 

 

Testing the Nikon Z6 for Astrophotography


Nikon Z Title

I put the new Nikon Z6 mirrorless camera through its paces for astrophotography.ย 

Following Sonyโ€™s lead, in late 2018 both Nikon and Canon released their entries to the full-frame mirrorless camera market.ย 

Here I review one of Nikonโ€™s new mirrorless models, the Z6, tested solely with astrophotography in mind. I did not test any of the auto-exposure, auto-focus, image stabilization, nor rapid-fire continuous mode features.ย 

For full specs and details on the Z-series cameras see Nikon USAโ€™s website.

Sony a7III vs Nikon Z6 copy

In my testing I compared the Nikon Z6 (at right above) to two competitive cameras, the relatively new Sony a7III mirrorless (at left above) and 2015-vintage Nikon D750 DSLR.

All three are โ€œentry-levelโ€ full-frame cameras, with 24 megapixels and in a similar $2,000 price league, though the older D750 now often sells at a considerable discount.


Disclosure

I should state at the outset that my conclusions are based on tests conducted over only three weeks in mid-winter 2019 while I had the camera on loan from Nikon Canada’s marketing company.ย 

I don’t own the camera and didn’t have many moonless nights during the loan period to capture a lot of “beauty” shots under the stars with the Z6.

Auroral Arc (January 10, 2019)
An arc of the auroral oval across the northern horizon on the night of January 10-11, 2019. With the Sigma 14mm lens and Nikon Z6 for testing.

However, I think my testing was sufficient to reveal the camera’s main traits of interest โ€” as well as deficiencies it might have โ€” for astrophotography.

I should also point out that I do not participate in โ€œaffiliate links,โ€ so I have no financial motivation to prompt you to buy gear from merchants.ย 

But if you buy my ebook (at right), which features reams of sections on camera and time-lapse gear, I would be very pleased!ย 


TL;DR Conclusions

In short โ€” I found the Nikon Z6 superb for astrophotography.ย 

Nikon Z6 Screens copy

Summary:

โ€ขย It offers as low a noise level as youโ€™ll find in a 24-megapixel full-frame camera, though its noise was not significantly lower than the competitive Sony a7III, nor even the older Nikon D750.ย 

โ€ขย The Z6โ€™s ISO-invariant sensor proved excellent when dealing with the dark underexposed shadows typical of Milky Way nightscapes.

โ€ขย The Live View was bright and easy to enhance to even brighter levels using the Movie mode to aid in framing nightscapes.ย 

โ€ขย When shooting deep-sky images through telescopes using long exposures, the Z6 did not exhibit any odd image artifacts such as edge vignetting or amplifier glows, unlike the Sony a7III. See my review of that camera in my blog from 2018.ย 

Recommendations:ย 

โ€ขย Current owners of Nikon cropped-frame cameras wanting to upgrade to full-frame would do well to consider a Z6 over any current Nikon DSLR.ย 

โ€ขย Anyone wanting a full-frame camera for astrophotography and happy to โ€œgo Nikonโ€ will find the Z6 nearly perfect for their needs.ย 


Nikon Z6 vs. Z7

Nikon Front View copy

I opted to test the Z6 over the more expensive Z7, as the 24-megapixel Z6 has 6-micron pixels resulting in lower noise (according to independent tests) than the 46 megapixel Z7 with its 4.4 micron pixels.ย 

In astrophotography, I feel low noise is critical, with 24-megapixel cameras hitting a sweet spot of noise vs. resolution.

However, if the higher resolution of the Z7 is important for your daytime photography needs, then Iโ€™m sure it will work well at night. The Nikon D850 DSLR, with a sensor similar to the Z7, has been proven by others to be a good astrophotography camera, albeit with higher noise than the lesser megapixel Nikons such as the D750 and Z6.

NOTE: Tap or click on images to download and display them full screen for closer inspection.


High ISO Noise

Comparison - Noise at 3 ISOs
The three 24-megapixel cameras compared at three high ISO levels in a close-up of a dark-sky nightscape.

To test noise in a real-world situation, I shot a dark nightscape scene with the three cameras, using a 24mm Sigma Art lens on the two Nikons, and a 24mm Canon lens on the Sony via a MetaBones adapter. I shot at ISOs from 800 to 12,800, typical of what we use in nightscapes and deep-sky images.ย 

The comparison set above shows performance at the higher ISOs of 3200 to 12,800. I saw very little difference among the trio, with the Nikon Z6 very similar to the Sony a7III, and with the four-year-old Nikon D750 holding up very well against the two new cameras.ย 

The comparison below shows the three cameras on another night and at ISO 3200.

Noise at 3200-3 Cameras
The three cameras compared for noise at properly exposed moonlit scenes at ISO 3200, a typical nightscape setting.

Both the Nikon Z6 and Sony a7III use a backside illuminated or “BSI” sensor, which in theory is promises to provide lower noise than a conventional CMOS sensor used in an older camera such as the D750.ย 

In practice I didnโ€™t see a marked difference, certainly not as much as the one- or even 1/2-stop improvement in noise I might have expected or hoped for.

Nevertheless, the Nikon Z6 provides as low a noise level as youโ€™ll find in a camera offering 24 megapixels, and will perform very well for all forms of astrophotography.ย 


ISO Invariance

Comparison - ISO Invariancy
The three cameras compared for ISO invariance at 0EV (well exposed) and -5EV (5 stops underexposed then brightened in processing).

Nikon and Sony both employ an โ€œISO-invariantโ€ signal flow in their sensor design. You can purposely underexpose by shooting at a lower ISO, then boost the exposure later โ€œin postโ€ and end up with a result similar to an image shot at a high ISO to begin with in the camera.ย 

I find this feature proves its worth when shooting Milky Way nightscapes that often have well-exposed skies but dark foregrounds lit only by starlight. Boosting the brightness of the landscape when developing the raw files reveals details in the scene without unduly introducing noise, banding, or other artifacts such as magenta tints.ย 

Thatโ€™s not true of โ€œISO variantโ€ sensors, such as in most Canon cameras. Such sensors are far less tolerant of underexposure and are prone to noise, banding, and discolouration in the brightened shadows.

See my test of the Canon 6D MkII for its performance under the differing demands of nightscape photography andย deep-sky imaging.

To test the Z6โ€™s ISO invariance (as shown above) I shot a dark nightscape at ISO 3200 for a properly exposed scene, and also at ISO 100 for an image underexposed by a massive 5 stops. I then boosted that image by 5 stops in exposure in Adobe Camera Raw. Thatโ€™s an extreme case to be sure.ย 

I found the Z6 provided very good ISO invariant performance, though with more chrominance specking than the Sony a7III and Nikon D750 at -5 EV.

Below is a less severe test, showing the Z6 properly exposed on a moonlit night and at 1 to 4 EV steps underexposed, then brightened in processing. Even the -4 EV image looks very good.

Comparison-ISO Invariancy in Moonlight
This series taken under moonlight shows that even images underexposed by -4 EV in ISO and boosted later by +4 EV in processing look similar for noise and image quality as an image properly exposed in the camera (at ISO 800 here).

In my testing, even with frames underexposed by -5 EV, I did not see any of the banding effects (due to the phase-detect auto-focus pixels) reported by others.ย 

As such, I judge the Z6 to be an excellent camera for nightscape shooting when we often want to extract detail in the shadows or dark foregrounds.ย 


Compressed vs. Uncompressed / Raw Large vs. Smallย 

Comparison - Z6 Large vs Medium RAW
Comparing Z6 images shot at full resolution and at Medium Raw size. to show resolution and noise differences.

The Z6, as do many Nikons, offers a choice of shooting 12-bit or 14-bit raws, and either compressed or uncompressed.ย 

I shot all my test images as 14-bit uncompressed raws, yielding 46 megabyte files with a resolution of 6048 x 4024 pixels. So I cannot comment on how good 12-bit compressed files are compared to what I shot. Astrophotography demands the best original data.ย 

Z6 Menu - Raw Formats

However, as the menu above shows, Nikon now also offers the option of shooting smaller raw sizes. The Medium Raw setting produces an image 4528 x 3016 pixels and a 18 megabyte file (in the files I shot), but with all the benefits of raw files in processing.

Nikon with Card Slot copy
The Z cameras use the XQD style memory cards and in a single card slot. The fast XQDs are ideal for recording 4K movies at high data rates but are more costly than the more common SD cards.

The Medium Raw option might be attractive when shooting time-lapses, where you might need to fit as many frames onto the single XQD card as possible, yet still have images large enough for final 4K movies.ย 

However, comparing a Large Raw to a Medium Raw did show a loss of resolution, as expected, with little gain in noise reduction.ย 

This is not like โ€œbinning pixelsโ€ in CCD cameras to increase signal-to-noise ratio. I prefer to never throw away information in the camera, to allow the option of creating the best quality still images from time-lapse frames later.ย 

Nevertheless, itโ€™s nice to see Nikon now offer this option on new models, a feature which has long been on Canon cameras.ย 


Star Image Quality

Orion Nebula, M42 and M43, with Nikon Z6
The Orion Nebula with the Nikon Z6

The Orion Nebula in Moonlight
The Orion Nebula with the Nikon D750

Above is the Orion Nebula with the D750 and with the Z6, both shot in moonlightย with the same 105mmย refractor telescope.

I did not find any evidence for โ€œstar-eatingโ€ that Sony mirrorless cameras have been accused of. (However, I did not find the Sony a7III guilty of eating stars either.) Star images looked as good in the Z6 as in the D750.ย 

M42 Blow-up in ACR
A single Orion Nebula image with the Z6 in a 600% blow-up in Adobe Camera Raw, showing clean artifact-free star images with good, natural colours.

Raw developers (Adobe, DxO, ON1, and others) decoded the Z6โ€™s Bayer-array NEF files fine, with no artifacts such as oddly-coloured or misshapen stars, which can arise in cameras lacking an anti-alias filter.ย 


LENR Dark framesย 

Z6 Dark Frame- No LENR
A blank long exposure with no LENR applied – click or tap to open the image full screen

Z6 Dark Frame-With LENR
A blank long exposure with LENR – tap or click to open the image full screen

Above, 8-minute exposures of nothing, taken with the lens cap on at room temperature:ย without LENR, andย with LENR, both boosted a lot in brightness and contrast toย exaggerate the visibility of any thermal noise. These show the reduction in noise speckling with LENR activated, and the clean result with the Z6. At small size you’llย likely see nothing butย black!

For deep-sky imaging a common practice is to shoot โ€œdark frames,โ€ images recording just the thermal noise that can then be subtracted from the image.ย 

The Long Exposure Noise Reduction feature offered by all cameras performs this dark frame subtraction internally and automatically by the camera for any exposures over one second long.ย 

I tested the Z6โ€™s LENR and found it worked well, doing the job to effectively reduce thermal noise (hot pixels) without adding any other artifacts.ย 

Z6 iMenu Screen
The rear screen “i” menu as I had it customized for my testing, with functions for astrophotography such as LENR assigned to the 12 boxes.

NOTE:

Some astrophotographers dismiss LENR and never use it. By contrast, I prefer to use LENR to do dark frame subtraction. Why? Through many comparison tests over the years I have found that separate dark frames taken later at night rarely do as good a job as LENR darks, because those separate darks are taken when the sensor temperature, and therefore the noise levels, are different than they were for the โ€œlightโ€ frames.ย 

I’ve found that dark frames taken later, then subtracted โ€œin postโ€ inevitably show less or little effect compared to images taken with LENR darks. Or worse, they add a myriad of pock-mark black specks to the image, adding noise and making the image look worse.

The benefit of LENR is lower noise. The penalty of LENR is that each image takes twice as long to shoot โ€” the length of the exposure + the length of the dark frame. Because โ€ฆ


As Expected on the Z6 โ€ฆ Thereโ€™s no LENR Dark Frame Buffer

Only Canon full-frame cameras offer this little known but wonderful feature for astrophotography. Turn on LENR and it is possible to shoot three (with the Canon 6D MkII) or four (with the Canon 6D) raw images in quick succession even with LENR turned on. The Canon 5D series also has this feature.ย 

The single dark frame kicks in and locks up the camera only after the series of โ€œlight framesโ€ are taken. This is excellent for taking a set of noise-reduced deep-sky images for later stacking without need for further โ€œimage calibration.โ€ย 

No Nikon has this dark frame buffer, not even the โ€œastronomicalโ€ D810a. And not the Z6.

ANOTHER NOTE:ย 

I have to mention this every time I describe Canonโ€™s dark frame buffer: It works only on full-frame Canons, and thereโ€™s no menu function to activate it. Just turn on LENR, fire the shutter, and when the first exposure is complete fire the shutter again. Then again for a third, and perhaps a fourth exposure. Only then does the LENR dark frame lock up the camera as โ€œBusyโ€ and prevent more exposures. That single dark frame gets applied to each of the previous โ€œlightโ€ frames, greatly reducingย the time it takes to shoot a set of dark-frameย subtracted images.ย 

But do note that Canon’s dark frame buffer will not work if…:

a) You leave Live View on. Don’t do that for any long exposure shooting.

b) You control the camera through the USB port via external software. It works only when controlling the camera via its internal intervalometer or via the shutter port using a hardware intervalometer.


Sensor Illuminationย 

M35 with Z6 & Traveler (4 Minutes)
A single 4-minute exposure of Messier 35 in moonlight at ISO 400 with the Z6 and 105mm apo refractor, with no flat fielding or lens correction applied, showing the clean edges and lack of amp glows. The darkening of the corners is inherent in the telescope optical system and is not from the camera.

With DSLRs deep-sky images shot through telescopes, then boosted for contrast in processing, usually exhibit a darkening along the bottom of the frame. This is caused by the upraised mirror shadowing the sensor slightly, an effect never noticed in normal photography.ย 

Mirrorless cameras should be free of this mirror box shadowing. The Sony a7III, however, still exhibits some edge shadows due to an odd metal mask in front of the sensor. It shouldnโ€™t be there and its edge darkening is a pain to eliminate in the final processing.ย 

As I show in my review of the a7III, the Sony also exhibits a purple edge glow in long-exposure deep-sky images, from an internal light source. Thatโ€™s a serious detriment to its use in deep-sky imaging.

Happily, the Z6 proved to be free of any such artifacts. Images are clean and evenly illuminated to the edges, as they should be. I saw no amp glows or other oddities that can show up under astrophotography use. The Z6 can produce superb deep-sky images.ย 


Red Sensitivity

M97 with Z6 & Traveler (4 Minutes)
Messer 97 planetary nebula and Messier 108 galaxy in a lightly processed single 4-minute exposure at ISO 1600 with the 105mm refractor, again showing a clean field. The glow at top right is from a Big Dipper star just off the edge of the field.

During my short test period, I was not able to shoot red nebulas under moonless conditions. So I canโ€™t say how well the Z6 performs for recording H-alpha regions compared to other โ€œstockโ€ cameras.ย 

However, I would not expect it to be any better, nor worse, than the competitors. Indeed, the stock Nikon D750 I have does a decent job at picking up red nebulas, though nowhere near as well as Nikonโ€™s sadly discontinued D180a. See my blog post from 2015 for an example shot with that camera.ย 

With the D810a gone, if it is deep red nebulosity you are after with a Nikon, then consider buying a filter-modified Z6 or having yours modified.ย 

Both LifePixel and Spencerโ€™s Cameraย offer to modify the Z6 and Z7 models. However, I have not used either of their services, so cannot vouch for them first hand.ย 


Live View Focusing and Framingย 

Z6 Live View Screen
An image of the back of the camera with a scene under moonlight, with the Z6 set to the highest ISO speed in the movie mode, to aid framing the scene at night.

For all astrophotography manually focusing with Live View is essential.ย And with mirrorless cameras there is no optical viewfinder to look through to frame scenes. You are dependent on the liveย electronic image (on the rear LCD screen or in the eye-level electronic viewfinder, or EVF) for seeing anything.

Thankfully, the Z6 presents a bright Live View image making it easy to frame, find, and focus on stars. Maximum zoom for precise focusing is 15x, good but not as good as the D750โ€™s 20x zoom level, but better than Canonโ€™s 10x maximum zoom in Live View.ย 

The Z6 lacks the a7IIIโ€™s wonderful Bright Monitoring function that temporarily ups the ISO to an extreme level, making it much easier to frame a dark night scene. However, something similar can be achieved with the Z6 by switching it temporarily to Movie mode, and having the ISO set to an extreme level.

As with most Nikons (and unlike Sonys), the Z6 remembers separate settings for the still and movie modes, making it easy to switch back and forth, in this case for a temporarily brightened Live View image to aid framing.ย 

Thatโ€™s very handy, and the Z6 works better than the D750 in this regard, providing a brighter Live View image, even with the D750โ€™s well-hidden Exposure Preview option turned on.ย 


Video Capabilityย 

Comparison - Movie Noise Levels
Comparing the three cameras using 1/25-second still frames grabbed from moonlit night movies (HD with the D750 and 4K with the Z6 and a7III) shot at ISO 51200, plus a similarly exposed frame from the a7III shot with a shutter speed of only 1/4 second allowing the slower ISO of 8000.

Where the Z6 pulls far ahead of the otherwise similar D750 is in its movie features.

The Z6 can shoot 4K video (3840 x 2160 pixels) at either 30, 25, or 24 frames per second. Using 24 frames per second and increasing the ISO to between 12,800 to 51,200 (the Z6 can go as high as ISO 204,800!) it is possible to shoot real-time video at night, such as of auroras.

But the auroras will have to be bright, as at 24 fps, the maximum shutter speed is 1/25-second, as you might expect.ย 

The a7III, by comparison, can shoot 4K movies at โ€œdraggedโ€ shutter speeds as slow as 1/4 second, even at 24 fps, making it possible to shoot auroras at lower and less noisy ISO speeds, albeit with some image jerkiness due to the longer exposures per frame.ย 

The D750 shoots only 1080 HD and, as shown above, produces very noisy movies at ISO 25,600 to 51,200.ย It’s barely usable for aurora videos.

The Z6 is much cleaner than the D750 at those high ISOs, no doubt due to far better internal processing of the movie frames. However, if night-sky 4K videos are an important goal, a camera from the Sony a7 series will be a better choice, if only because of the option for slower dragged shutter speeds.

For examples of real-time auroras shot with the Sony a7III see my music videos shot in Yellowknife and in Norway.ย 


Battery Life

Nikon Z6 Battery copy

The Z6 uses the EN-EL15b battery compatible with the battery and charger used for the D750. But the โ€œbโ€ variant allows for in-camera charging via the USB port.ย 

In room temperature tests the Z6 lasted for 1500 exposures, as many as the D750 was able to take in a side-by-side test. That was with the screens off.

At night, in winter temperatures of -10 degrees C (14ยฐ F), the Z6 lasted for three hours worth of continuous shooting, both for long deep-sky exposure sets and for a test time-lapse I shot, shown below.ย 

A time-lapse movie,ย downsized here to HD from the full-size originals, shot with the Z6 and its internal intervalometer, from twilight through to moonrise on a winter night.ย Processed with Camera Raw and LRTimelapse.ย 

However, with any mirrorless camera, you can extend battery life by minimizing use of the LCD screen and eye-level EVF. The Z6 has a handy and dedicated button for shutting off those screens when they arenโ€™t needed during a shoot.

The days of mirrorless cameras needing a handful of batteries just to get through a few hours of shooting are gone.ย 


Lens and Telescope Compatibilityย 

Nikon with Sigma and FTZ copy
A 14mm Sigma Art lens with the Nikon FTZ lens adapter needed to attach any “legacy” F-mount lens to the Z6.

As with all mirrorless cameras, the Nikon Z cameras use a new lens mount, one that is incompatible with the decades-old Nikon F mount.ย 

The Z mount is wider and can accommodate wider-angle and faster lenses than the old F mount ever could, and in a smaller package. While we have yet to see those lenses appear, in theory thatโ€™s the good news.

The bad news is that youโ€™ll need Nikonโ€™s FTZ lens adapter to use any of your existing Nikon F-mount lenses on either the Z6 or Z7. As of this writing, Nikon is supplying an FTZ free with every Z body purchase.ย 

I got an FTZ with my loaner Z6 and it worked very well, allowing even third-party lenses like my Sigma Art lenses to focus at the same point as they normally do (not true of some thIrd-party adapters), preserving the lensโ€™s optical performance. Autofocus functions all worked fine and fast.

Nikon with Scope Adapter and FTZ copy
The FTZ adapter needed to attach the Z6 to a telescope camera adapter (equipped with a standard Nikon T-ring) and field flattener lens for a refractor.

Youโ€™ll also need the FTZ adapter for use on a telescope, as shown above, to go from your telescopeโ€™s camera adapter, with its existing Nikon T-ring, to the Z6 body.ย 

T-rings are becoming available for the Z-mount,ย but even these third-party adapters are actually extension tubes, not just rings.

The reason is that the field flattener or coma corrector lenses often required with telescopes are designed to work best with the longer lens-to-sensor distance of a DSLR body. The FTZ adapter provides the necessary spacing, as do third-party adapters.ย 

Nikon Z6 FTZ Foot copy
The FTZ lens adapter has its own tripod foot, useful for balancing front-heavy lenses like the big Sigma here.

The only drawback to the FTZ is that any tripod plate attached to the camera body itself likely has to come off, and the tripod foot incorporated into the FTZ used instead. I found myself often having to swap locations for the tripod plate, an inconvenience.ย 


Camera Controller Compatibilityย 

Nikon with Ports copy
The port side of the Z6, with the DC2 shutter remote jack at bottom, and HDMI and USB-C ports above. There’s also a mic and headphone jack for video use.

Since it uses the same Nikon-type DC2 shutter port as the D750, the Z6 it should be compatible with most remote hardware releases and time-lapse motion controllers that operate a Nikon through the shutter port. An example are the controllers from SYRP.

On the other hand, time-lapse devices and external intervalometers that run Nikons through the USB port might need to have their firmware or apps updated to work with the Z6.

For example, as of early May 2019, CamRanger lists the Z6 as a supported camera; the Arsenal โ€œsmart controllerโ€ does not. Nor does Alpine Labs for their Radian and Pulse controllers, nor TimeLapse+ for its excellent View bramping intervalometer. Check with your supplier.

For those who like to use laptops to run their camera at the telescope, I found the Windows program Astro Photography Tool (v3.63) worked fine with the Z6, in this case connecting to the cameraโ€™s USB-C port using the USB-C to USB-A cable that comes with the camera. This allows APT to shift not only shutter speed, but also ISO and aperture under scripted sequences.ย 

However, BackyardNikon v2.0, current as of April 2019, does not list the Z6 as a supported camera.ย 


Raw File Compatibilityย 

Z6 Raw open in Raw Therapee
A Z6 Raw NEF file open in Raw Therapee 5.6, showing good star images and de-Bayering.

Inevitably, raw files from brand new cameras cannot be read by any raw developer programs other than the one supplied by the manufacturer, Nikon Capture NX in this case. However, even by the time I did my testing in winter 2019 all the major software suppliers had updated their programs to open Z6 files.ย 

Adobe Lightroom and Photoshop, Affinity Photo, DxO PhotoLab, Luminar 3, ON1 PhotoRAW, and the open-source Raw Therapee all open the Z6โ€™s NEF raw files just fine.ย 

Z6 Raw in PixInsight
PixInsight 1.8.6 failing to open a Z6 raw NEF file.

Specialized programs for processing astronomy images might be another story. For example, as of v1.08.06, PixInsight, a favourite program among astrophotographers, does not open Z6 raw files. Nor does Nebulosity v4. But check with the developers for updates.ย 


Other Features for Astrophotographyย 

Here are other Nikon Z6 features I found of value for astrophotography, and for operating the camera at night.ย 

Nikon with Looking Right copy

Tilting LCD Screenย 

Like the Nikon D750 and Sony A7III, the Z6 offers a tilting LCD screen great for use on a telescope or tripod when aimed up at the sky. However, the screen does not flip out and reverse, a feature useful for vloggers, but seldom needed for astrophotography.ย 

Nikon Z6 Top Screen copy
Showing the top OLED screen and dedicated ISO button that is easy to access in the dark. It works in conjunction with the top dial.

OLED Top Screen (Above)

The Sony doesnโ€™t have one, and Canonโ€™s low-cost mirrorless Rp also lacks one. But the top-mounted OLED screen of the Z6 is a great convenience for astrophotography. It makes it possible to monitor camera status and battery life during a shoot, even with the rear LCD screen turned off to prolong battery life.

Z6 Menu - Quick Menu

Touch Screenย 

Sonyโ€™s implementation of touch-screen functions is limited to just choosing autofocus points. By contrast, the Nikon Z6 offers a full range of touchscreen functions, making it easy to navigate menus and choose settings.ย 

I do wish there was anย option, as there is with Pentax, to tint the menus red for preserving night vision.

Z6 Menu - Intervalometer

Built-in Intervalometer

As with other Nikons, the Z6 offers an internal intervalometer capable of shooting time-lapses, just as long as individual exposures donโ€™t need to be longer than 30 seconds.ย 

In addition, thereโ€™s the Exposure Smoothing option which, as I have found with the D750, is great for smoothing flickering in time-lapses shot using auto exposure.ย 

Sony has only just added an intervalometer to the a7III with their v3 firmware update, but with no exposure smoothing.ย 

Z6 Menu - Silent Shooting

Custom i Menu / Custom Function Buttonsย 

The Sony a7III has four custom function buttons users can assign to commonly used commands, for quick access. For example, I assign one Custom button to the Bright Monitoring function which is otherwise utterly hidden in the menus, but superb for framing nightscapes, if only you know itโ€™s there!ย 

The Nikon Z6 has two custom buttons beside the lens mount. However, I found it easier to use the โ€œiโ€ menu (shown above) by populating it with those functions I use at night for astrophotography. Itโ€™s then easy to call them up and adjust them on the touch screen.

Thankfully, the Z6โ€™s dedicated ISO button is now on top of the camera, making it much easier to find at night than the awkwardly placed ISO button on the back of the D750, which I am always mistaking for the Image Quality button, which you do not want to adjust by mistake.ย 

Nikon Z6-My Menu

My Menuย 

As most cameras do, the Z6 also has a โ€œMy Menuโ€ page which you can also populate with favourite menu commands.ย 

Nikon D750 and Z6 copy
The D750 (left) compared to the smaller and lighter Z6 (right). This shows the wider Z lens mount compared to Nikon’s old F-mount standard.

Lighter Weight / Smaller Size

The Z6 provides similar imaging performance, if not better (for movies) than the D750, and in a smaller and lighter camera, weighing 200 grams (0.44 pounds) less than the D750.ย Being able to downsize my equipment mass is a welcome plus to going mirrorless.

Comparison - Z6 Mech vs Silent Shutter
Extreme 800% blow-ups of the Moon show a slightly sharper image with the Z6 set to Silent Shutter.

Electronic Front Curtain Shutter / Silent Shootingย 

By design, mirrorless cameras lack any vibration from a bouncing mirror. But even the mechanical shutter can impart vibration and blurring to high-magnification images taken through telescopes.ย 

The electronic front curtain shutter (lacking in the D750) helps eliminate this, while the Silent Shooting mode does just that โ€” it makes the Z6 utterly quiet and vibration free when shooting, as all the shutter functions are now electronic. This is great for lunar and planetary imaging.ย 


Whatโ€™s Missing for Astrophotography (not much!)

Bulb Timer for Long Exposures

While the Z6 has a Bulb setting, there is no Bulb Timer as there is with Canonโ€™s recent cameras. A Bulb Timer would allow setting long Bulb exposures of any length in the camera, though Canon’s cannot be combined with the intervalometer.ย 

Instead, the Nikon must be used with an external Intervalometer for any exposures over 30 seconds long. Any number of units are compatible with the Z6, through its shutter port which is the same type DC2 jack used in the D750.

Z6 Menu - Multiple Exposures

In-Camera Image Stackingย to Raws

The Z6 does offer the ability to stack up to 10 images in the camera, a feature also offered by Canon and Pentax. Images can be blended with a Lighten (for star trails) or Average (for noise smoothing) mode.ย 

However, unlike with Canon and Pentax, the result is a compressed JPG not a raw file, making this feature of little value for serious imaging. Plus with a maximum of only 10 exposures of up to 30-seconds each, the ability to stack star trails โ€œin cameraโ€ is limited.ย 

Illuminated Buttonsย 

Unlike the top-end D850, the Z6โ€™s buttons are not illuminated, but then again neither are the Z7โ€™s.


As a bonus โ€” the Nikon 35mm S-Series Lens

Nikkor 35mm Lens Test
The upper left frame corner of a tracked star image shot with the 35mm S lens wide open at f/1.8 and stopped down at third stop increments.

With the Z6 I also received a Nikkor 35mm f/1.8 S lens made for the Z-mount, as the lens perhaps best suited for nightscape imaging out of the native Z-mount lenses from Nikon. See Nikon’s website for the listing.ย 

If thereโ€™s a downside to the Z-series Nikons itโ€™s the limited number of native lenses that are available now from Nikon, and likely in the future from anyone, due to Nikon not making it easy for other lens companies to design for the new Z mount.ย 

In testing the 35mm Nikkor on tracked shots, stars showed excellent on- and off-axis image quality, even wide open at f/1.8. Coma, astigmatism, spherical aberration, and lateral chromatic aberration were all well controlled.ย 

However, as with most lenses now offered for mirrorless cameras, the focus is โ€œby-wireโ€ using a ring that doesnโ€™t mechanically adjust the focus. As a result, the focus ring turns continuously and lacks a focus scale.ย 

So it is not possible to manually preset the lens to an infinity mark, as nightscape photographers often like to do. Focusing must be done each night.ย 

Until there is a greater selection of native lenses for the Z cameras, astrophotographers will need to use the FTZ adapter and their existing Nikon F-mount or third-party Nikon-mount lenses with the Zs.


Recommendationsย 

I was impressed with the Z6.ย 

The Owl Nebula and Messier 108 Galaxy
The Owl Nebula, Messier 97, a planetary nebula in our galaxy, and the edge-on spiral galaxy Messier 108, paired below the Bowl of the Big Dipper in Ursa Major. This is a stack of 5 x 4-minute exposures at ISO 1600 with the Nikon Z6 taken as part of testing. This was through the Astro-Physics Traveler refractor at f/6 with the Hotech field flattener and FTZ adapter.

For any owner of a Nikon cropped-frame DSLR (from the 3000, 5000, or 7000 series for example) wanting to upgrade to full-frame for astrophotography I would suggest moving to the Z6 over choosing a current DSLR.ย 

Mirrorless is the way of the future. And the Z6 will yield lower noise than most, if not all, of Nikonโ€™s cropped-frame cameras.

Nikkor 35mm S Lens copy
The Z6 with the Nikkor 35mm f/1.8 S lens native for the Z mount.

For owners of current Nikon DSLRs, especially a 24-megapixel camera such as the D750, moving to a Z6 will not provide a significant improvement in image quality for still images.ย 

But … it will provide 4K video and much better low-light video performance than older DSLRs. So if it is aurora videos you are after, the Z6 will work well, though not quite as well as a Sony alpha.ย 

In all, thereโ€™s little downside to the Z6 for astrophotography, and some significant advantages: low noise, bright live view, clean artifact-free sensor images, touchscreen convenience, silent shooting, low-light 4K video, all in a lighter weight body than most full-frame DSLRs.ย 

I highly recommend the Nikon Z6.ย 

โ€” Alan, April 30, 2019 / ยฉ 2019 Alan Dyer / AmazingSky.comย 

 

 

Testing ON1 Photo RAW for Astrophotography


ON1 Testing Title

Can the new version of ON1 Photo RAW match Photoshop for astrophotography?ย 

The short TL;DR answer: No.

But … as always, it depends. So do read on.


Released in mid-November 2018, the latest version of ON1 Photo RAW greatly improves a non-destructive workflow. Combining Browsing, Cataloging, Raw Developing, with newly improved Layers capabilities, ON1 is out to compete with Adobe’s Creative Cloud photo suite โ€“ Lightroom, Camera Raw, Bridge, and Photoshop โ€“ for those looking for a non-subscription alternative.

Many reviewers love the new ON1 โ€“ for “normal” photography.

But can it replace Adobe for night sky photos? I put ON1 Photo RAW 2019 through its paces for the demanding tasks of processing nightscapes, time-lapses, and deep-sky astrophotos.


The Conclusions

In my eBook “How to Photograph and Process Nightscapes and Time-Lapses” (linked to at right) I present dozens of processing tutorials, including several on how to use ON1 Photo RAW, but the 2018 edition. I was critical of many aspects of the old version, primarily of its destructive workflow when going from its Develop and Effects modules to the limited Layers module of the 2018 edition.

I’m glad to see many of the shortfalls have been addressed, with the 2019 edition offering a much better workflow allowing layering of raw images while maintaining access to all the original raw settings and adjustments. You no longer have to flatten and commit to image settings to layer them for composites. When working with Layers you are no longer locked out of key functions such as cropping.

I won’t detail all the changes to ON1 2019 but they are significant and welcome.

The question I had was: Are they enough for high-quality astrophotos in a non-destructive workflow, Adobe Photoshop’s fortรฉ.

While ON1 Photo RAW 2019 is much better, I concluded it still isn’t a full replacement of Adobe’s Creative Cloud suite, as least not for astrophotography.

NOTE: All images can be downloaded as high-res versions for closer inspection.ย 


ON1 2019 is Better, But for Astrophotography …

  1. Functions in Layers are still limited. For example, there is no stacking and averaging for noise smoothing. Affinity Photo has those.
  2. Filters, though abundant for artistic special effect “looks,” are limited in basic but essential functions. There is no Median filter, for one.
  3. Despite a proliferation of contrast controls, for deep-sky images (nebulas and galaxies) I was still not able to achieve the quality of images I’ve been used to with Photoshop.
  4. The lack of support for third-party plug-ins means ON1 cannot work with essential time-lapse programs such as Timelapse Workflow or LRTimelapse.

ON1 Final Composite
A finished nightscape composite, with stacked exposures for the ground and stacked and tracked exposures for the sky, layered and blended in ON1.


Recommendations

Nightscapes: ON1 Photo RAW 2019 works acceptably well for nightscape still images:

  1. Its improved layering and excellent masking functions are great for blending separate ground and sky images, or for applying masked adjustments to selected areas.

Time-Lapses: ON1 works is just adequate for basic time-lapse processing:

  1. Yes, you can develop one image and apply its settings to hundreds of images in a set, then export them for assembly into a movie. But there is no way to vary those settings over time, as you can by mating Lightroom to LRTimelapse.
  2. As with the 2018 edition, you still cannot copy and paste masked local adjustments from image to image, limiting their use.
  3. Exporting those images is slow.

Deep-Sky: ON1 is not a program I can recommend for deep-sky image processing:

  1. Stars inevitably end up with unsightly sharpening haloes.
  2. De-Bayering artifacts add blocky textures to the sky background.
  3. And all the contrast controls still don’t provide the “snap” and quality I’m used to with Photoshop when working with low-contrast subjects.

Library / Browse Functions

ON1 Browse Module
ON1 cannot catalog or display movie files or Photoshop’s PSB files (but then again with PSBs neither can Lightroom!).

ON1 is sold first and foremost as a replacement for Adobe Lightroom, and to that extent it can work well. Unlike Lightroom, ON1 allows browsing and working on images without having to import them formally into a catalog.

However, you can create a catalog if you wish, one that can be viewed even if the original images are not “on-line.” The mystery seems to be where ON1 puts its catalog file on your hard drive. I was not able to find it, to manually back it up. Other programs, such as Lightroom and Capture One, locate their catalogs out in the open in the Pictures folder.

For those really wanting a divorce from Adobe, ON1 now offers an intelligent AI-based function for importing Lightroom catalogs and transferring all your Lightroom settings you’ve applied to raw files to ON1’s equivalent controls.

However, while ON1 can read Photoshop PSD files, it will flatten them, so you would lose access to all the original image layers.

ON1’s Browse module is good, with many of the same functions as Lightroom, such as “smart collections.” Affinity Photo โ€“ perhaps ON1’s closest competitor as a Photoshop replacement โ€“ still lacks anything like it.

But I found ON1’s Browse module buggy, often taking a long while to allow access into a folder, presumably while it is rendering image previews.

There are no plug-ins or extensions for exporting directly to or synching to social media and photo sharing sites.


Nightscape Processing โ€“ Developing Raw Images

ON1 Before and After Processing
On the left, a raw image as it came out of the camera. On the right, after developing (with Develop and Effects module settings applied) in ON1.

For this test I used the same nightscape image I threw at Adobe competitors a year ago, in a test of a dozen or more raw developers. It is a 2-minute tracked exposure with a Sigma 20mm Art lens at f/2 and Nikon D750 at ISO 1600.

ON1 did a fairly good job. Some of its special effect filters, such a Dynamic Contrast, Glow, and Sunshine, can help bring out the Milky Way, though do add an artistic “look” to an image which you might or might not like.

Below, I compare Adobe Camera Raw (ACR) to ON1. It was tough to get ON1’s image looking the same as ACR’s result, but then again, perhaps that’s not the point. Does it just look good? Yes, it does.

ON1 & ACR Raw Image Comparison
On the left, a single raw image developed with Adobe Camera Raw. On the right, the same image with ON1 and its basic Develop and more advanced Effects settings.

Compared to Adobe Camera Raw, which has a good array of basic settings, ON1 has most of those and more, in the form of many special Effects, with many combined as one-click Presets, as shown below.

ON1 Presets
ON1 offers a huge array of Presets that apply combinations of its filters with one click from the Browse module.

Aย few presets and individual filters โ€“ the aforementioned Dynamic Contrast and Glow โ€“ are valuable. However, most of ON1’s filters and presets will not be useful for astrophotography, unless you are after highly artistic and unnatural effects.

Noise Reduction and Lens Correction

ON1 Noise Reduction
On the left, an image in ON1 without any Noise Reduction. On the right, with noise reduction and sharpening (under Details) applied with the settings shown.

Critical to all astrophotography is excellent noise reduction. ON1 does a fine job here, with good smoothing of noise without harming details.

Lens Correction works OK. It detected the 20mm Sigma art lens and automatically applied distortion correction, but not any vignetting (light “fall-off”) correction, perhaps the most important correction in nightscape work. You have to dial this in manually by eye, a major deficiency.

By comparison, ACR applies both distortion and vignetting correction automatically. It also includes settings for many manual lenses that you can select and apply in a click. For example, ACR (and Lightroom) includes settings for popular Rokinon and Venus Optics manual lenses; ON1 does not.

Hot Pixel Removal

Hot Pixel Removal Comparison
On the left, ACR with noise reduction applied (it offers no user-selectable Hot Pixel Removal tool). In the middle, ON1 with Remove Hot Pixels turned on; on the right, with it turned off โ€“ showing more hot pixels than ACR does.

I shot the example image on a warm summer night and without using in-camera Long Exposure Noise Reduction (to keep the gap between exposures short when shooting sets of tracked and untracked exposures for later compositing).

However, the penalty for not using LENR to expedite the image taking is a ground filled with hot pixels. While Adobe Camera Raw does have some level of hot pixel removal working “under the hood,” many specks remained.

ON1 showed more hot pixels, until you clicked Remove Hot Pixels, found under Details. As shown at centre above, it did a decent job getting rid of the worst offenders.

But as I’ll show later, the penalty is that stars now look distorted and sometimes double, or you get the outright removal of stars. ON1 doesn’t do a good job distinguishing between true sharp-edged hot pixels and the softer images of stars. Indeed, it tends to over sharpen stars.

A competitor, Capture One 11, does a better job, with an adjustable Single Pixel removal slider, so you can at least select the level of star loss you are willing to tolerate to get rid of hot pixels.

Star Image Quality

ON1 & ACR Star Image Comparison
On the left, a 700% blow-up of the stars in Adobe Camera Raw. On the right, the same image processed in ON1 and exported out as a PSD.

Yes, we are pixel peeping here, but that’s what we do in astrophotography. A lot!

Stars in ON1 don’t look as good as in Camera Raw. Inevitably, as you add contrast enhancements, stars in ON1 start to exhibit dark and unsightly “sharpening haloes” not present in ACR, despite me applying similar levels of sharpening and contrast boosts to each version of the image.

Camera Raw has been accused of producing images that are not as sharp as with other programs such as Capture One and ON1.

There’s a reason. Other programs over-sharpen, and it shows here.

We can get away with it here in wide-field images, but not later with deep-sky close-ups. I don’t like it. And it is unavoidable. The haloes are there, albeit at a low level, even with no sharpening or contrast enhancements applied, and no matter what image profile is selected (I used ON1 Standard throughout).

De-Bayering Artifacts

ON1-Debayer
ON1, with contrast boosts applied but with no sharpening or noise reduction, shows star haloes, while the sky shows a blocky pattern at the pixel level in high ISO shots.

ACR-Debayer
Adobe Camera Raw, with similar settings but also no sharpening or noise reduction, shows a smooth and uniform sky background.

You might have to download and closely inspect these images to see the effect, but ON1’s de-Bayering routine exhibits a cross-hatched blocky pattern at the pixel-peeping level. ACR does not.

I see this same effect with some other raw developers. For example, the free Raw Therapee shows it with many of its choices for de-Bayering algorithms, but not all. Of the more than a dozen raw developers I tested a year ago, ACR and DxO PhotoLab had (and still have) the most artifact-free de-Bayering and smoothest noise reduction

Again, we can get away with some pixel-level artifacts here, but not later, in deep-sky processing.


Nightscape Processing โ€” Layering and Compositing

ON1 Perfect Brush
ON1’s adjustable “Perfect Brush” option for precise masking around edges and objects isn’t quite as effective as Photoshop’s Quick Selection Tool.

Compositing

The 2018 version of ON1 forced you to destructively flatten images when bringing them into the Layers module.

The 2019 version of ON1 improves that. It is now possible to composite several raw files into one image and still retain all the original Develop and Effects settings for non-destructive work.

You can then use a range of masking tools to mask in or out the sky.

For the example above, I have stacked tracked and untracked exposures, and am starting to mask out the trailed stars from the untracked exposure layer.

To do this with Adobe, you would have to open the developed raw files in Photoshop (ideally using “smart objects” to retain the link back to the raw files). But with ON1 we stay within the same program, to retain access to non-destructive settings. Very nice!

To add masks, ON1 2019 does not have the equivalent of Photoshop’s excellent Quick Selection Tool for selecting the sky or ground. It does have a “Perfect Brush” option which uses the tonal value of the pixels below it, rather than detecting edges, to avoid “painting over the lines.”

While the Perfect Brush does a decent job, it still requires a lot of hand painting to create an accurate mask without holes and defects. There is no non-destructive “Select and Mask” refinement option as in Photoshop.

Yes, ON1’s Refine Brush and Chisel Mask tools can help clean up a mask edge but are destructive to the mask. That’s not acceptable to my non-destructive mindset!

Local Adjustmentsย 

ON1 Masking Adjustments
Local Adjustments can be painted in or out with classic and easy-to-adjust and view masks and layers, rather than adjustment pins used by many raw developers such as ACR.

The masking tools are also applicable to adding “Local Adjustments” to any image layer, to brighten or darken regions of an image for example.

These work well and I find them more intuitive than the “pins” ACR uses on raw files, or DxO PhotoLab’s quirky “U-Point” interface.

ON1’s Local Adjustments work more like Photoshop’s Adjustment Layers and are similarly non-destructive. Excellent.

Luminosity Masks

ON1 Luminosity Masking
ON1 has one-click Luminosity masking, an excellent feature.

A very powerful feature of ON1 is its built-in Luminosity masking.

Yes, Camera Raw now has Range Masks, and Photoshop can be used to create luminosity masks, but making Photoshop’s luminosity masks easily adjustable requires purchasing third-party extension panels.

ON1 can create an adjustable and non-destructive luminosity mask on any image or adjustment layer with a click.

While such masks, based on the brightness of areas, aren’t so useful for low-contrast images like the Milky Way scene above, they can be very powerful for merging high-contrast images (though ON1 also has an HDR function not tested here).

Glow Effect
ON1’s handy Orton-style Glow effect, here with a Luminosity mask applied. The mask can be adjusted with the Levels and Window sliders, and applied to a range of colors as well.

ON1 has the advantage here. Its Luminosity masks are a great feature for compositing exposures or for working on regions of bright and dark in an image.

Final Composite

ON1 Final Composite
A finished nightscape composite, with stacked exposures for the ground and stacked and tracked exposures for the sky, layered and blended in ON1.

Here again is the final result, above.

It is not just one image each for the sky and ground, but is instead a stack of four images for each half of the composite, to smooth noise. This form of stacking is somewhat unique to astrophotography, and is commonly used to reduce noise in nightscapes and in deep-sky images, as shown later.

Stacking

ON1-Layer Opacities
This shows an intermediate step in creating the final composite shown above: Four sky layers are stacked, with opacities as shown, which has the effect of smoothing noise. But to continue working on the image requires making a single “New Stamped Layer” out of the group of four โ€“ in this case, the sky layers. The same can be done for the four ground layers.

Here I show how you have to stack images in ON1.

Unlike Photoshop and Affinity Photo, ON1 does not have the ability to merge images automatically into a stack and apply a mathematical averaging to the stack, usually a Mean or Median stack mode. The averaging of the image content is what reduces the random noise.

Instead, with ON1 you have perform an “old school” method of average stacking โ€“ by changing the opacity of the layers, so that Layer 2 = 50%, Layer 3 = 33%, Layer 4 = 25%, and so on. The result is identical to performing a Mean stack mode in Photoshop or Affinity.

Fine, except there is no way to perform a Median stack, which can be helpful for eliminating odd elements present in only one frame, perhaps an aircraft trail.

Copy and Paste Settings

ON1 Pasting Settings
ON1 allows easy copying and pasting of settings from one raw image to others, with the annoying exception of Local Adjustments and their masks.

Before we even get to the stacking stage, we have to develop and process all the images in a set. Unlike Lightroom or Camera Raw, ON1 can’t develop and synchronize settings to a set of images at once. You can work on only one image at a time.

So, you work on one image (one of the sky images here), then Copy and Paste its settings to the other images in the set. I show the Paste dialog box here.

This works OK, though I did find some bugs โ€“ the masks for some global Effects layers did not copy properly; they copied inverted, as black instead of white masks.

However, Luminosity masks did copy from image to image, which is surprising considering the next point.

The greater limitation is that no Local Adjustments (ones with masks to paint in a correction to a selected area) copy from one image to another … except ones with gradient masks. Why the restriction?

So as wonderful as ON1’s masking tools might be, they aren’t of any use if you want to copy their masked adjustments across several images, or, as shown next, to a large time-lapse set.

While Camera Raw’s and Lightroom’s Local Adjustment pins are more awkward to work with, they do copy across as many images as you like.


Time-Lapse Processing

ON1 Copy & Paste
ON1 does allow developing one image in a set, then copying and pasting its settings to perhaps hundreds of other images in a time-lapse set.

A few Adobe competitors, such as Affinity Photo (as of this writing) simply can’t do this.

By comparison, with the exception of Local Adjustments,ย ON1 does have good functions for Copying and Pasting Settings. These are essential for processing a set of hundreds of time-lapse frames.

ON1 Export
This is ON1’s Export dialog box, set up here to export the developed raw files into another “intermediate” set of 4K-sized JPGs for movie assembly.

Once all the images are processed โ€“ whether it be with ON1 or any other program โ€“ the frames have to exported out to an intermediate set of JPGs for assembly into a movie by third-party software. ON1 itself can’t assemble movies, but then again neither can Lightroom (as least not very well), though Photoshop can, through its video editing functions.

For my test set of 220 frames, each with several masked Effects layers, ON1 took 2 hours and 40 minutes to perform the export to 4K JPGs. Photoshop, through its Image Processor utility, took 1 hour and 30 minutes to export the same set, developed similarly and with several local adjustment pins.

ON1 did the job but was slow.

A greater limitation is that, unlike Lightroom, ON1 does not accept any third party plug-ins (it serves as a plug-in for other programs). That means ON1 is not compatible with what I feel are essential programs for advanced time-lapse processing: either Timelapse Workflow (from https://www.timelapseworkflow.com) or the industry-standard LRTimelapse (from https://lrtimelapse.com).

Both programs work with Lightroom to perform incremental adjustments to settings over a set of images, based on the settings of several keyframes.

Lacking the ability to work with these programs means ON1 is not a program for serious and professional time-lapse processing.


Deep-Sky Processing

ON1-Tracked Milky Way
A tracked 2-minute exposure of the Cygnus Milky Way, with a Sony a7III camera at ISO 800 and Venus Optics Laowa 15mm lens at f/2, developed in ON1.

ACR-Tracked Milky Way
The same Milky Way image developed in Adobe Camera Raw. It looks better!

Wide-Angle Milky Way

Now we come to the most demanding task: processing long exposures of the deep-sky, such as wide-angle Milky Way shots and close-ups of nebulas and galaxies taken through telescopes. All require applying generous levels of contrast enhancement.

As the above example shows, try as I might, I could not get my test image of the Milky Way to look as good with ON1 as it did with Adobe Camera Raw. Despite the many ways to increase contrast in ON1 (Contrast, Midtones, Curves, Structure, Haze, Dynamic Contrast and more!), the result still looked flat and with more prominent sky gradients than with ACR.

And remember, with ACR that’s just the start of a processing workflow. You can then take the developed raw file into Photoshop for even more precise work.

With ON1, its effects and filters all you have to work with. Yes, that simplifies the workflow, but its choices are more limited than with Photoshop, despite ON1’s huge number of Presets.

Deep-Sky Close-Ups

ON1 Processed M31
The Andromeda Galaxy, in a stack of six tracked and auto-guided 8-minute exposures with a stock Canon 6D MkII through an 80mm f/6 refractor.

Photoshop Processed M31
The same set of six exposures, stacked and processed with ACR and Photoshop, with multiple masked adjustment layers as at right. The result looks better.

Similarly, taking a popular deep-sky subject, the Andromeda Galaxy, aka M31, and processing the same original images with ON1 and ACR/Photoshop resulted in what I think is a better-looking result with Photoshop.

Of course, it’s possible to change the look of such highly processed images with the application of various Curves and masked adjustment layers. And I’m more expert with Photoshop than with ON1.

But … as with the Cygnus Milky Way image, I just couldn’t get Andromeda looking as good in ON1. It always looked a little flat.

Dynamic Contrast did help snap up the galaxy’s dark lanes, but at the cost of “crunchy” stars, as I show next. A luminosity “star mask” might help protect the stars, but I think the background sky will inevitably suffer from the de-Bayering artifacts.

Star and Background Sky Image Quality

ON1 Processed M31-Close-Up
A 400% close-up of the final Andromeda Galaxy image. It shows haloed stars and a textured and noisy sky background.

Photoshop Processed M31-Close-Up
The same area blown up 400% of the Photoshop version of the Andromeda Galaxy image. Stars and sky look smoother and more natural.

As I showed with the nightscape image, stars in ON1 end up looking too “crunchy,” with dark halos from over sharpening, and also with the blocky de-Bayering artifacts now showing up in the sky.

I feel it is not possible to avoid dark star haloes, as any application of contrast enhancements, so essential for these types of objects, brings them out, even if you back off sharpening at the raw development stage, or apply star masks.

ON1 Processed M31-With & Without
On the left, the image before any processing applied; on the right, after the level of processing needed for such deep-sky images. What starts out looking OK, turns messy.

ON1 is applying too much sharpening “under the hood.” That might “wow” casual daytime photographers into thinking ON1 is making their photos look better, but it is detrimental to deep-sky images. Star haloes are a sign of poor processing.

Noise and Hot Pixels

ON1 With & Without NR and Hot Pixels
With and without noise reduction and hot pixel removal shows stars becoming lost and misshapen with the Remove Hot Pixel option.

ON1’s noise reduction is quite good, and by itself does little harm to image details.

But turn on the Remove Hot Pixel button and stars start to be eaten. Faint stars fade out and brighter stars get distorted into double shapes or have holes in them.

Hot pixel removal is a nice option to have, but for these types of images it does too much harm to be useful. Use LENR or take dark frames, best practices in any case.

Image Alignment and Registration

ON1 Auto-Alignment
The six Andromeda images stacked then “Auto-Aligned” in ON1, with just the top (first) and bottom (last) images turned on here. with the top image switched to Difference blend mode to show any mis-alignment.

Photoshop Auto-Alignment
The same set stacked and “Auto-Aligned” in Photoshop, with the same first and last images turned on and blended with Difference. PS’s alignment is much better, indicated by the image “blacking out” as the two registered frames cancel out.

Before any processing of deep-sky images is possible, it is first necessary to stack and align them, to make up for slight shifts from image to image, usually due to the mount not being perfectly polar aligned. Such shifts can be both translational (left-right, up-down) and rotational (turning about the guide star).

New to ON1 2019 is an Auto-Align Layers function. It worked OK but not nearly as well as Photoshop’s routine. In my test images of M31, ON1 didn’t perform enough rotation.

Once stacked and aligned, and as I showed above, you then have to manually change the opacities of each layer to blend them for noise smoothing.

By comparison, Photoshop has a wonderful Statistics script (under File>Scripts) that will automatically stack, align, then mean or median average the images, and turn the result into a non-destructive smart object, all in one fell swoop. I use it all the time for deep-sky images. There’s no need for separate programs such as Deep-Sky Stacker.

In ON1, however, all that has to be done manually, step-by-step.ย ON1 does do the job, just not as well.


Wrap-Up

M31 from ON1
The final M31, Andromeda Galaxy image processed with ON1.

ON1 Photo RAW 2019 is a major improvement, primarily in providing a more seamless and less destructive workflow.

Think of it as Lightroom with Layers!ย 

But it isn’t Photoshop.

Dynamic Contrast
ON1’s useful Dynamic Contrast filter. A little goes a long way.

True to ON1’s heritage as a special effect plug-in, it has some fine Effect filters, such as Dynamic Contrast above, ones I sometimes use from within Photoshop as plug-in smart filters.

Under Sharpen, ON1 does offer a High Pass option, a popular method for sharpening deep-sky objects.

Missing Filters and Adjustments

But for astrophoto use, ON1 is missing a lot of basic but essential filters for pixel-level touch-ups. Here’s a short list:

โ€ข Missing are Median, Dust & Scratches, Radial Blur, Shake Reduction, and Smart Sharpen, just to mention a handful of filters I find useful for astrophotography, among the dozens of others Photoshop has, but ON1 does not. But then again, neither does Lightroom, another example of how ON1 is more light Lightroom with layers and not Photoshop.

ON1 Color Adjustment
ON1’s selective Color Adjustment. OK, but where’s the Black and Neutrals?

โ€ข While ON1 has many basic adjustments for color and contrast, its version of Photoshop’s Selective Color lacks Neutral or Black sliders, great for making fine changes to color balance in astrophotos.

โ€ข While there is a Curves panel, it has no equivalent to Photoshop’s “Targeted Adjustment Tool” for clicking on a region of an image to automatically add an inflection point at the right spot on the curve. This is immensely useful for deep-sky images.

โ€ข Also lacking is a basic Levels adjustment. I can live without it, but most astrophotographers would find this a deal-breaker.

โ€ข On the other hand, hard-core deep-sky photographers who do most of their processing in specialized programs such as PixInsight, using Photoshop or Lightroom only to perform final touch-ups, might find ON1 perfectly fine. Try it!

Saving and Exporting

ON1 saves its layered images as proprietary .onphoto files and does so automatically. There is noย Save command, only a final Export command. As such it is possible to make changes you then decide you don’t like … but too late! The image has already been saved, writing over your earlier good version. Nor can you Save As … a file name of your choice. Annoying!

Opening a layered .onphoto file (even with ON1 itself already open) can take a minute or more for it to render and become editable.

Once you are happy with an image, you can Export the final .onphoto version as a layered .PSD file but the masks ON1 exports to the Photoshop layers may not match the ones you had back in ON1 for opacity. So the exported .PSD file doesn’t look like what you were working on. That’s a bug.

Only exporting a flattened TIFF file gets you a result that matches your ON1 file, but it is now flattened.

Bugs and Cost

I encountered a number of other bugs, ones bad enough to lock up ON1 now and then. I’ve even seen ON1’s own gurus encounter bugs with masking during their live tutorials. These will no doubt get fixed in 2019.x upgrades over the next few months.

But by late 2019 we will no doubt be offered ON1 Photo RAW 2020 for another $80 upgrade fee, over the original $100 to $120 purchase price. True, there’s no subscription, but ON1 still costs a modest annual fee, presuming you want the latest features.

Now, I have absolutely no problem with that, and ON1 2019 is a significant improvement.

However, I found that for astrophotography it still isn’t there yet as a complete replacement for Adobe.

But don’t take my word for it. Download the trial copy and test it for yourself.

โ€” Alan, November 22, 2018 / ยฉ 2018 Alan Dyer/AmazingSky.comย 

 

My 2019 Amazing Sky Calendar


2019 Amazing Sky Calendar Cover

My annual Amazing Sky Calendar is out!

My 2019 Amazing Sky Calendar is now out and available for FREE download as a PDF from my website page.

Once you’re on that page, scroll down for the link to the PDF.

Each month includes many dates and diagrams for celestial sights and space exploration events and anniversaries.

You can then print the PDF locally if you wish.

Do share the web page URL or this blog post.ย However, the PDF itself is for your personal use only. Enjoy!

โ€” Alan, October 1, 2018 / ยฉ 2018 Alan Dyer / www.amazingsky.com

 

 

Testing the Sony a7III for Astrophotography


Milky Way Rising at Dino Park

I put the new Sony a7III mirrorless camera through its paces for the features and functions we need to shoot the night sky.

Sonyโ€™s a7III camera has enjoyed rave reviews since its introduction earlier in 2018. Most tests focus on its superb auto exposure and auto focus capabilities that rival much more costly cameras, including Sonyโ€™s own a7rIII and a9.ย 

For astrophotography, none of those auto functions are of any value. We shoot everything on manual. Indeed, the ease of manually focusing in Live View is a key function.ย 

In my testing I compared the Sony a7III to two competitive DSLRs, the Canon 6D MkII and Nikon D750.

All three are โ€œentry-levelโ€ full-frame cameras, with 24 to 26 megapixels and in a similar price league of $1,500 (Nikon) to 2,000 (Sony).ย 

I tested a Sony a7III purchased locally. It was not supplied to me by Sony in return for an โ€œinfluentialโ€ blog post.

I did this testing in preparation for the new third edition of my Nightscapes and Time-Lapse eBook, which includes information on Sony mirrorless cameras, as well as many, many other updates and additions!

NOTE: Click or Tap on most images to bring them up full-frame for inspection.

Milky Way Rising at Dino Park
MILKY WAY AT DINOSAUR PARK Aย stack of 2 x 90-second exposures for the ground, to smooth noise, and at f/2.8 for better depth of field, plus a single 30-second untracked exposure at f/2 for the sky. All with the Laowa 15mm lens and Sony a7III at ISO 3200.


Mirrorless vs. DSLR

Sony a7III with Loawa 15mm
COMPACT CAMERA and LENS
The Sony a7III with the compact but fast Laowa Venus Optics 15mm f/2 lens.

As with Sonyโ€™s other popular Alpha 7 and 9 series cameras, the new Alpha 7III is a full-frame mirrorless camera, a class of camera Canon and Nikon have yet to offer, though models are rumoured or promised.ย 

In the meantime, Sony commands the full-frame mirrorless market.

As its name implies, a mirrorless camera lacks the reflex mirror of a digital single lens reflex camera that, in a DSLR, provides the light path for framing the scene though the optical viewfinder.ย 

Sony Live View
SONY LIVE VIEW
The Sony a7IIIโ€™s excellent Live View screen display. You can see the Milky Way!

In a mirrorless, the camera remains in โ€œlive viewโ€ all the time, with the sensor always feeding a live image to either or both the rear LCD screen and electronic viewfinder (EVF). While you can look through and frame using the EVF as you would with a DSLR, you are looking at an electronic image from the sensor, not an optical image from the lens.ย 

The advantage of purely electronic viewing is that the image you are previewing matches the image youโ€™ll capture, at least for short exposures. The disadvantage is that full-time live view draws more power, with mirrorless cameras notorious for being battery hungry.ย 

Other mirrorless advantages include:

  • Compact size and lighter weight, yet offering all the image quality of a full-frame DSLR.
  • The thinner body allows the use of lenses from any manufacturer, albeit requiring the right adapter, an additional expense.
  • Lenses developed natively for mirrorless models can be smaller and lighter. An example is the Laowa 15mm f/2 I used for some of the testing.
  • The design lends itself to video shooting, with many mirrorless cameras offering 4K as standard, while often in DSLRs only high-end models do.
  • More rapid-fire burst modes and quieter shutters are a plus for action and wedding photographers, though they are of limited value for astrophotography.

Points of Comparison

Camera Trio-Sony, Nikon, Canon
CAMERA TRIO
The Sony a7III, Nikon D750, and Canon 6D Mark II. Note the size difference.

In testing the Sony a7III I ignored all the auto functions. Instead, I concentrated on those points I felt of most concern to astrophotographers, such as:

  • Noise levels
  • Effectiveness of Long Exposure Noise Reduction (LENR)ย 
  • Quality of Raw files, such as sharpness of stars
  • Brightness of Live View for framing and focusing
  • Uniformity of sensor illumination
  • Compatibility for time-lapse imaging
  • Battery life

TL;DR Conclusions

Sony a7III and Meade 70mm
DEEP-SKY TEST
The North America Nebula with the Sony a7III and a Meade 70mm f/5 astrographic refractor, for a single 4-minute exposure at ISO 1600. The reds have been boosted in processing.

Noise
Levels of luminance and chrominance noise were excellent and similar to โ€“ but surprisingly not better than โ€“ the Nikon D750.

Star Eater
The Star Eater is effectively gone. Stars are not smoothed out in long exposures.ย 

ISO Invarianceย 
The Sony exhibited good โ€“ though not great โ€“ โ€œISO invariantโ€ performance.

Dark Framesย 
Dark frame subtraction using Long Exposure Noise Reduction removed most โ€“ but not all โ€“ hot pixels from thermal noise.ย 

Live View Focusing and Framing
Live View was absolutely superb, though the outstanding Bright Monitoring function is as well-hidden as Sony could possibly make it.ย 

Sensor Illumination Uniformity
The Sony showed some slight edge-of-frame shadowing from the mask in front of the sensor, as well as a weak purple amp glow.

Featuresย 
โ€ขย The a7III lacks any internal intervalometer or ability to add one via an app. But it is compatible with many external intervalometers and controllers.

โ€ขย The a7IIIโ€™s red sensitivity for recording H-Alpha-emitting nebulas was poor.ย 

โ€ข It lacks the โ€œlight-frameโ€ buffer offered by full-frame Canons that allows shooting several frames in quick succession even with LENR turned on.

Video Capabilityย 
The a7III offers 4K video and, at 24 frames-per-second, is full-frame. Shutter speeds can be as slow as 1/4-second, allowing real-time aurora shooting at reasonable ISO speeds.ย 

Battery Life
Shooting typical 400-frame time-lapses used about 40% of the battery capacity, similar to the other DSLRs.ย 

Overall Recommendations
The Sony a7III is a superb camera for still and time-lapse nightscape shooting, and excellent for real-time aurora videos. It is good, though not great, for long-exposure deep-sky imaging.ย 

Liberty Schoolhouse with Star Trails
STAR TRAILS and AURORAย With the Laowa 15mm lens and Sony a7III, for 155 exposures, all 20 seconds at f/2.8 and at ISO 800, and taken as part of a 360-frame time-lapse.


Noise

The Sony a7III uses a sensor that is โ€œBackside Illuminated,โ€ a feature that promises to improve low-light performance and reduce noise.ย 

I saw no great benefit from the BSI sensor. Noise at typical astrophoto ISO speeds โ€“ 800 to 6400 โ€“ were about equal to the four-year-old Nikon D750.ย 

That was a bit surprising. I expected the new BSI-equipped Sony to better the Nikon by about a stop. It did not. This emphasizes just how good the Nikon D750 is.ย 

Nevertheless, noise performance of the Sony a7III was still excellent, with both the Sony and Nikon handily outperforming the Canon 6D MkII, with its slightly smaller pixels, by about a stop in noise levels.ย 

NOTE: I performed all Raw developing with Adobe Camera Raw v10.3. It is possible some of the artifacts I saw are due to ACR not handling the a7IIIโ€™s .ARW files as well as it should. But to develop all the images from Sony, Nikon, and Canon equally for comparisons, ACR is the best choice.ย 

1-Sony vs Nikon vs Canon Noise
COMPARING NOISE
The Sony a7III exhibited noise levels similar to the Nikon D750 at high ISOs, with the Sony and Nikon each about a stop better for noise than the Canon 6D MkII.

2A-Sony vs Nikon vs Canon at 3200
NOISE AT ISO 3200
At ISO 3200, a common nightscape ISO speed, all three cameras performed well in this moonlit scene. The Canon shows a darker sky as its images were taken a few minutes later. The Nikon had the Sigma 14mm Art lens; the Canon and Sony used the same Rokinon 14mm SP lens.

2B-Sony vs Nikon vs Canon at 6400
NOISE AT ISO 6400
At ISO 6400, the Canon begins to show excessive noise, about a stop worse than the Nikon and Sony. No luminance noise reduction was applied to these images. All cameras show an equal number of stars recorded.


ISO Invariance

Both the Sony and Nikon use sensor and signal path designs that are โ€œISO invariant.โ€ As a result, images shot underexposed at slower ISOs, then boosted in exposure later in processing look identical to properly exposed high-ISO images. Well, almost.

The Sony still showed some discoloration artifacts and added noise when boosting images by +4 EV that the Nikon did not. Even with uncompressed Raws, the Sony was not quite as ISO invariant as the Nikon, though the difference shows up only under extreme push-processing of badly underexposed frames.ย 

Plus, the Sony was far better than the Canon 6D MkIIโ€™s โ€œISO variantโ€ sensor. Canon really needs to improve their sensors to keep in the game.ย 

3A-Sony vs Nikon vs Canon ISO Invariancy
ISO INVARIANCE COMPARISON
Here I shot all three cameras at ISO 6400 for a correct exposure for the scene, and also at ISO 1600 and ISO 400, for images 2 and 4 stops underexposed respectively. These were then boosted in Adobe Camera Raw by 2 and 4 stops in Exposure Value (EV) to compensate. With ISO invariant sensors the boosted images should look similar to the well-exposed image.

3B-Sony vs Nikon vs Canon ISO Invariancy CU
ISO INVARIANCE CLOSE-UP
A closeup of the scene shows the ISO variant Canon exhibited more noise and magenta discoloration in the +4 EV boosted image. The Nikon looks very clean, but the Sony also shows discoloration, green here, and an increase in noise. These are all uncompressed 14-bit Raw files.

4-Sony vs Nikon ISO Invariancy
SONY vs. NIKON
Comparing just the two ISO-invariant cameras, the Sony and the Nikon, on another night, shows a similar performance difference when boosting underexposed slow-ISO images later in Camera Raw. The Sony begins to show more noise and now a magenta discoloration in the +3 and +4 EV images, similar to, but not as badly as does the ISO-variant Canon 6D MkII.


Compressed vs. Uncompressedย 

Sony-Comp-UnCompThe Sony a7III offers a choice of shooting Uncompressed or Compressed Raw files. Uncompressed Raws are 47 Mb in size; Compressed Raws are 24 Mb.ย 

In well-exposed images, I saw little difference in image quality.ย 

But the dark shadows in underexposed nightscapes withstood shadow recovery better in the uncompressed files. Compressed files showed more noise and magenta discoloration in the shadows.ย 

It is not clear if Sonyโ€™s compressed Raws are 12-bit vs. 14-bit for uncompressed files.ย 

Nevertheless, for the demands of nightscape and deep-sky shooting and processing, I suggest shooting Uncompressed Raws. Use Compressed only if you plan to take lots of time-lapse frames and need to conserve memory card space on extended shoots.ย 

5A-Sony UnCompressed vs Compressed at -1EV
UNCOMPRESSED vs. COMPRESSED
Here I compare any image degradation from using compressed vs. uncompressed Raws, and from employing Long Exposure Noise Reduction. Images are only slightly underexposed and boosted by +1 EV in Camera Raw. Shadow noise is similar in all images, with the ones taken with LENR on showing elimination of colored hot pixels, as they should.

5B-Sony UnCompressed vs Compressed at -4EV
UNCOMPRESSED vs. COMPRESSED at -4EV
The same scene but now underexposed by 4 stops and boosted by +4 EV later shows greater differences. The compressed image shows more noise and discoloration, and the images taken with LENR on, while eliminating hot pixels, show more random luminance noise. Keep in mind, these are vastly underexposed images.ย 

6-Sony Comp vs Uncomp + DF
UNCOMPRESSED vs. COMPRESSED DEEP-SKY
A real-world deep-sky example shows the same comparison. All images are well-exposed, for tracked and guided 4-minute exposures. The ones taken with LENR on show fewer hot pixels. The compressed images appear identical to the uncompressed files for noise and star content.


Star Eater (Updated March 27, 2021)

Over the last year or so, firmware updates from Sony introduced a much-publicized penchant for Sony Alphas to โ€œeatโ€ stars even in Raw files, apparently due to an internal noise reduction or anti-aliasing routine users could not turn off. Stars were smoothed away along with the noise in exposures longer than 3.2 seconds in some Sony cameras (longer than 30 seconds in others).

I feel that in the a7III the Star Eater has been largely vanquished.

While others beg to differ and claim this camera still eats stars, they offer no evidence of it other than graphs and charts, not A-B photos of actual tracked starfields taken with the Sony vs. another camera thought not to eat stars.

As the images below show, there is a very slight one-pixel-level softening that kicks in at 4 seconds and longer but it did not eat or wipe out stars. Stars are visible to the same limiting magnitude and close double stars are just as well resolved across all exposures. Indeed, at slower ISOs and longer exposures, more stars are visible.

I saw none of the extreme effects reported by others with other Sonys, where masses of faint stars disappeared or turned into multi-colored blotches. It is possible the effect is still present in other Sony Alpha models. I have not tested those.

But in the a7III, I did not see any significant “star eating” in any long exposures even up to the 4 minutes I used for some deep-sky shots. In images taken at the same time with other cameras not accused of star eating, the Sony showed just as many faint stars as the competitors. Stars were visible to just as faint a limiting magnitude, and that’s what counts, NOT graphs and charts, especially when such results are not shown for other cameras.

In short, long exposures showed just as many stars as did short exposures.

This was true whether I was shooting compressed or uncompressed Raws, with or without Long Exposure Noise Reduction. Neither compression nor LENR invoked โ€œstar eating.โ€ย 

Sony-Star Eater Series @ 200%
STAR EATER SERIES at 200%
This series of tracked images (shown here blown up 200%) goes from 2 seconds to 2 minutes, with decreasing ISO speed to equalize the exposure value across the series. Between 3.2s and 4s a very slight one-pixel-level softening does kick in, reducing noise and very slightly blurring stars. Yet, just as many stars are recorded and are resolved, and at the lower ISOs/longer exposures more stars are visible because faint stars are not lost in the noise.

Sony-Star Eater Series @ 400%
STAR EATER SERIES at 400%
This is the same series as above but now blown up 400% to better reveal the very subtle change in pixel-level sharpness as exposure lengthened from 3.2 to 4 seconds. Noise (most noticeable in the trees) is reduced and stars are very slightly softened. But none are “eaten” or wiped out. And star colors are not affected, though very small stars are sometimes green, an effect seen in other cameras due to de-Bayering artifacts.

7A-Sony vs Canon for Star Eater v1
STAR EATER DEEP-SKY #1
Tracked deep-sky images through a telescope using 4-minute exposures show the Sony a7III recording an equal number of faint stars as the Canon 6D MkII. No luminance noise reduction was applied to these images in processing.

7B-Sony vs Canon for Star Eater v2
STAR EATER DEEP-SKY #2
Another example with 4-minute exposures again demonstrates no problems recording faint stars. The Canon does show more noise than the Sony. No noise reduction was applied in processing.ย 

7C-Sony vs Nikon for Star Eater
SONY and NIKON COMPARED
For yet more evidence, this is a comparison of the Sony a7III vs. the Nikon D750 in tracked 90-second exposures with 14mm lenses. Again, the Sony records just as many stars as the Nikon.


LENR Dark framesย 

Sony-LENRFor elimination of hot pixels from thermal noise I prefer to use Long Exposure Noise Reduction when possible for nightscape and deep-sky images, especially on warm summer nights.

Exceptions are images taken for star trail stacking and for time-lapses, images that must be taken in quick succession, with minimal time gap between frames.

Turning on LENR did eliminate most hot pixels in long exposures, but not all. A few remained. Also, when boosting the exposure a lot in processing, the images taken with LENR on showed more shot and read noise than non-LENR frames.ย 

The dark frame the camera was taking and subtracting was actually adding some noise, perhaps due to a temperature difference. The cause is not clear.ย 

Sony advises that when using LENR Raw images are recorded with only 12-bit depth, not 14-bit. This might be a contributing factor. Yet frames taken with LENR on were the same 47 Mb size as normal uncompressed frames.

For those who think this is normal for LENR use, the Nikon D750 shows nothing like this โ€“ frames taken with LENR on are free of all hot pixels and do not show more shot or read noise, nor deterioration of shadow detail from lower bit depths.

However, I emphasize that the noise increase from using LENR with the Sony was visible only when severely boosting underexposed images in processing.ย 

In most shooting situations, I found using LENR provided the overriding positive benefit of reducing hot pixels. It just needs to be better, Sony!

8A-Sony Dark Frames (W and WO LENR)
SONY WITH AND WITHOUT LENR
These are 4-minute exposures of dark frames (i.e. the lens cap on!) taken at room temperature with and without Long Exposure Noise Reduction. In the Sony, LENR did not eliminate all hot pixels nor the magenta amp glow at the left edge. LENR also added a background level of fine noise. These have had exposure and contrast increased to exaggerate the differences.

8B-Nikon Dark Frames (W and WO LENR)
NIKON WITH AND WITHOUT LENR
Dark frames taken with the Nikon D750 under the same circumstances and processed the same show none of the residual hot pixels and added background noise when LENR is employed. Nor is there any amp glow anywhere along the frame edges.

8C-Sony With and Without LENR
SONY REAL-WORLD LENR COMPARISON
A real-world example with the Sony, with a properly exposed nightscape, shows that the ill effects of using LENR donโ€™t show up under normal processing. You do get the benefit of reduced hot pixels in shadows, especially on a warm night like this was. This is a blow-up of the lower corner of the frame, as indicated.


Sensor Illuminationย 

How evenly an image is illuminated is a common factor when testing lenses.ย 

But astrophotography, which often requires extreme contrast boosts, reveals non-uniform illumination of the sensor itself, regardless of the optics, originating from hardware elements in front of the sensor casting shadows onto the sensor.ย 

This is most noticeable โ€“ indeed usually only noticeable โ€“ย when shooting deep-sky targets though telescopes.ย 

With DSLRs it is the raised mirror which often casts a shadow, produced a dark vignetted band along the bottom of the frame. Its extent varies from camera model to model.

With a mirrorless camera the sensor is not set far back in a mirror box, as it is in a DSLR. As such, I would have expected a more uniformly illuminated sensor.ย 

Sony a7III - Sensor CU
SENSOR CLOSE-UPย showing intruding mask edges.

Instead, I saw a slight shadowing at the top and bottom edges but just at the corners. This is from a thin metal mask in front of the sensor. It intrudes into the light path ever so slightly. It shouldnโ€™t.ย 

This is an annoying flaw, though applying โ€œflat fieldsโ€ or ad hoc local adjustments should eliminate this. But that’s a nuisance to do, and should not be necessary with a mirrorless camera.

Worse is that long deep-sky exposures at high ISOs also exhibited a faint purple glow at the left edge, perhaps from heat from nearby electronics, a so-called โ€œamp glow.โ€ Or I’ve read where this is from an internal infrared source near the sensor.

Taking a dark frame with LENR did not eliminate this, and it should, demonstrating again that for whatever reason in the a7III LENR is not as effective as it should be.ย 

I have not seen such “amp” glows in cameras (at least in the DSLRs Iโ€™ve used) for a number of years, so seeing it in the new Sony a7III was another surprise.ย 

This would be much tougher to eliminate in deep-sky images where the extreme contrast boosts we typically apply to images of nebulas and galaxies will accentuate any odd glows.ย 

UPDATE: March 27, 2021 โ€” Subsequent firmware updates seem to have eliminated this amp glow. One supplier of filter-modified cameras, Spencer’s Camera, who had refused to modify Sonys because of this glow, now lists many Sony Alphas as suitable for modification. However, the sensor masks and “green stars” (described below) still make the Sony a7III less desirable for deep-sky imaging than other mirrorless cameras I’ve tested.

9A-Sony Full Field
SONY FIELD ILLUMINATION #1
The full field of a deep-sky image taken through an f/5 70mm astrographic refractor shows the minor level of edge darkening at the corners from shadowing of the sensor in the Sony.

New Sony Blog Example
SONY FIELD ILLUMINATION #2 The full field of a deep-sky image taken through an f/6 105mm refractor shows the level of edge darkening at the edges from shadowing of the sensor in the Sony, and the purple “amplifier” glow at the left edge present in all very long exposures.


Red Sensitivity

When shooting deep-sky objects, particularly red nebulas, we like a camera to have a less aggressive infrared cutoff filter, to pick up as much of the deep red Hydrogen-Alpha emission line as possible.ย 

The Sony showed poor deep-red sensitivity, though not unlike other cameras. It was a little worse than the stock Canon 6D MkII.ย 

This isnโ€™t a huge detriment, as anyone who really wants to go after deep nebulosity must use a โ€œfilter-modifiedโ€ camera anyway.ย 

Canon and Nikon both offered factory modified cameras at one time, notably the Canon 60Da and Nikon D810a. Sony doesnโ€™t have an โ€œaโ€ model mirrorless.

To get the most out of the Sony for deep-sky imaging you would have to have it modified by a third-party, though the amp glow described above makes it a poor choice for modification.

10-Canon5D vs 6D vs Sony (Red Nebula)
RED SENSITIVITY COMPARED
Three deep-sky exposures compare cameras for red sensitivity: a filter-modified Canon 5D MkII, a stock Canon 6D MkII, and the stock Sony a7III. As expected the filter-modified camera picks up much more red nebulosity. The Sony doesnโ€™t do quite as well as the Canon 6D MkII.


Live View Focusing and Framingย 

Up to now my report on the Sony a7III hasnโ€™t shown as glowing a performance as all the YouTube reviews would have you believe.ย 

But Live Focus is where the a7III really stands out. I love it!

In Live View it is possible to make the image so bright you can actually see the Milky Way live on screen! Wow! This makes it so easy to frame nightscapes and deep-sky fields. ย 

Sony-Custom Buttoms
FINDING BRIGHT MONITORING
The excellent Bright Monitoring function is accessible only off the Custom Key menu where it appears as a choice on the Display/Auto Review2 page (below) that can be assigned to a C button.

But this special โ€œBright Monitoringโ€ mode is as well hidden as Sony could make it. Unless you actually read the full-length 642-page PDF manual (you have to download it), you wonโ€™t know about it. Bright Monitoring does not appear in any of the in-camera menus you can scroll through, so you wonโ€™t stumble across it.

Instead, you have to go to the Camera Settings 2 page, then select Still Imageโ€“Custom Key. In the menu options that appear you can now scroll to one called Bright Monitoring. Surprise! Assign it to one of the hardware Custom C buttons. I put it on C2, making it easy to call up when needed.ย 

Sony-Bright Monitoring

The other Live View function that works well, but also needs assigning to a C button is the Camera Settings 1 > Focus Magnifier. I put this on C1. It magnifies the Live View by 5.9x or 11.7x, allowing for precise manual focusing on a star.ย 

Sony-LiveViewDisp

Two other functions are useful for Live View:ย 

  • Camera Settings 2 > Live View Display > Setting Effect ON. This allows the Live View image to reflect the camera settings in use, better simulating the actual exposure, even without Bright Monitoring on.
  • Camera Settings 1 > Peaking Setting. Turning this ON superimposes a shimmering effect on parts of an image judged in focus. This might be an aid, or an annoyance. Try it.ย 

In all, the Sony provides superb, if well-hidden, Live View options that make accurately framing and focusing a nightscape or time-lapse scene a joy.ย 


Great Features for Astrophotographyย 

Here are some other Sony a7III features I found of value for astrophotography, and for operating the camera at night.ย 

Sony a7III with Tilt Screen
SONY TILTING SCREEN It tilts up and down but does not flip out as with the Canon 6D MkII’s. Still, this is a neck- and back-saving feature for astrophotography.

Tilting LCD Screenย 
Like the Nikon D750, the Sonyโ€™s screen tilts vertically up and down, great for use when on a telescope, or on any tripod when aimed up at the sky. As photographers age, this becomes a more essential feature!

Sony-CustomKey

Custom Buttonsย 
The four C buttons can be programmed for oft-used functions, making them easy to access at night. Standard functions such as ISO and Drive Mode are easy to get at on the thumb wheel, unlike the Nikon D750 where I am forever hunting for the ISO or Focus Zoom buttons, or the Canon 6D MkII which successfully hides the Focus Zoom and Playback buttons at night.

Sony-MyMenu

My Menuย 
In new models, Sony now offers the option of a final โ€œMy Menuโ€ page which you can populate with often-used functions from the other 35 pages of menu commands!

Adaptability to Many Lensesย 
Using the right lens adapter (I use one from Metabones), it is possible to use lenses with mounts made for Canon, Nikon, Sigma and others. Plus there are an increasing number of lenses from third parties offered with native Sony E-mounts. This is good news, as astrophotography requires fast, high-quality lenses, and the Sony allows more choices.

Lighter Weight / Smaller Size
The compact a7III body weighs a measured 750 grams, vs. 900 grams each for the Nikon D750 and Canon 6D MkII. The lower weight can be helpful for use on lightweight telescopes, on small motion control devices, and for simply keeping weight and bulk down when traveling.ย 

Sony a7III - Dual Slots

Dual Card Slotsย 
Not essential, but having two card slots is very helpful, for backup, for handling overflows from very long time-lapse shoots, or assigning them for stills vs. movies, or Raws vs. JPGs.ย Only Slot 1 will work with the fastest UHS II cards that are needed for recording the highestย quality 4K video.

USB Powerย 
It is possible to power the camera though the USB port (indeed thatโ€™s how you charge the battery, as no separate battery charger is supplied as standard, a deficiency). This might be useful for long shoots, though likely as not that same USB port will be needed for an intervalometer or motion control device. But if the Sony had a built-in intervalometerโ€ฆ!

Sony-DispInfo

Display Options
To reduce battery drain it is possible to turn off the EVF completely โ€“ I find I never use it at night โ€“ and to turn off the LCD display when shooting, though the latter is an option you have to activate to add to the Display buttonโ€™s various modes.ย 

The downside is that when shooting is underway you get no reassuring indication anything is happening, except for a brief LED flash when an image is written to a card. ย 

Sony-ECurtain

Electronic Front Curtain Shutter
Most DSLRs do not offer this, but the Sonyโ€™s option of an electronic front curtain shutter and the additional Silent Shooting mode completely eliminates vibration, useful for some high-magnification shooting through telephotos and telescopes.

11-Sony Shutter Vibration
LUNAR CLOSE-UPS COMPARED
This trio compares closeups of the Moon taken with and without electronic front curtain shutter. All were taken through a 130mm refractor telescope at f/12 using a Barlow lens. The image with e-shutter and in Silent Mode is a tad sharper, but that could be just as much from variations in seeing conditions as from the lower vibration from using the electronic shutter.


Whatโ€™s Missing for Astrophotography

Intervalometerย โ€” NOW INCLUDED!
UPDATE: In April 2019 Sony issued a v3 Firmware update for the a7III which added an internal intervalometer. I’ve used this new function and it works very well.

I had originally remarked that this useful function was missing. But no more! Thank you Sony!

While a built-in intervalometer is not essential, I find I often do use the Canon and Nikon in-camera intervalometers for simple shoots. So it is great to have one available on the Sony. However, like other brands’ internal intervalometers Sony’s is good only for exposures up to 30 seconds long.

Bulb Timer or Long Exposures
However, while the Sony has a Bulb setting there is no Bulb Timer as there is with the Canon. The Bulb Timer would allow setting long Bulb exposures of any length in the camera.ย 

Instead, for any exposures over 30 seconds long (or time-lapses with >30-second-long frames) the Sony must be used with an external Intervalometer. I use a $50 Vello unit, and it works very well. It controls the Sony through the cameraโ€™s Multi USB port.

In-Camera Image Stackingย 
Also missing, and present on most new Canons, are Multiple Exposure modes for in-camera stacking of exposures in a Brighten mode (for star trails) or Averaging mode (for noise smoothing).ย 

Yes, this can all be done later in processing, but having the camera do the stacking can often be convenient, and great for beginners, as long as they understand what those functions do, or even that they exist!

Time-Lapse Smoothingย 
When using its internal intervalometer, the Nikon D750 has an excellent Exposure Smoothing option. This does a fine job smoothing frame-to-frame flickering in time-lapses, something the Canon cannot do. Nor the Sony, as it has no intervalometer at all.

Light Frame Buffer in LENR
This feature is little known and utilized, and only Canon full-frame cameras offer it. Turn on LENR and it is possible to shoot three (with the 6D MkII) or four (with the 6D) Raw images in quick succession even with LENR turned on. The Canon 5D series also has this.ย 

The dark frame kicks in and locks up the camera only after the series of โ€œlight framesโ€ are taken. This is wonderful for taking a set of noise-reduced deep-sky images for later stacking. Nikons donโ€™t have this, not even the D810a, and not Sonys.ย 

Illuminated Buttonsย 
The Sonyโ€™s buttons are not illuminated. While these might add glows to long exposure images, if they could be designed not to do that (i.e. they turn off during exposures), lit buttons would be very handy at night.ย 

Limited Touch Screen Functionsย 
An alternative would be an LCD screen that was touch sensitive. The Sony a7IIIโ€™s screen is, but only to select an area for auto focus or zooming up an image in playback. The Canon 6D MkII has a fully functional touch screen which can be, quite literally, handy at night. ย 

Sony a7III with Vello Intervalometer
INTERVALOMETER
For time-lapses, the Sony must be used with an external intervalometer like this Vello unit.


Video Capabilityย 

Hereโ€™s another area where the new Sony a7III really shines.ย 

It offers 4K (or more precisely UltraHD) video recording for videos of 3840 x 2160 pixels. (True 4K is actually 4096 x 2160 pixels.)

With a fast enough UHS-II Class card it can record 4K video up to 30 frames per second and at a bit rate of either 60 or 100 Mbps.ย 

Sony-MovieSetting

At 24 fps videos are full-frame with no cropping. Hurray! You can take full advantage of wide-angle lenses, great for auroras. At 30 fps, 4K videos are cropped with a 1.2x crop factor.

In Movie Mode ISO speeds go up to ISO 102,400, but are pretty noisy, if unusable at such speeds.ย 

But when shooting aurora videos I found, to my surprise, I could “drag” the shutter speeds as slow as 1/4-second, fully 4 stops better than the Nikonโ€™s slowest shutter speed of 1/60 second in Full HD, and 3 stops better than the Canonโ€™s slowest movie shutter of 1/30 second.ย 

Coupled with a fast f/1.4 to f/2 lens, the slow shutter speed allows real-time aurora shooting at โ€œonlyโ€ ISO 6400 to 12,800, for quite acceptable levels of noise. I am very impressed!ย 

Real-time video of auroras is not possible with anything like this quality with the Nikon (Iโ€™ve used it often), and absolutely not with the Canon. And neither are 4K.ย 

Is the a7III as good for low-light video as the Sony a7s models, with their larger 8.5-micron pixels?ย 

I would assume not, but not having an a7s (either Mark I or II) to test I canโ€™t say for sure. But the a7III should do the job for bright auroras, the ones with rapid motion worth recording with video, plus offer 24 megapixels for high-quality stills of all sky subjects.ย 

I think itโ€™s a great camera for both astrophoto stills and video.

12A-Aurora Video Screen Shot
AURORA VIDEO FRAME
This is a frame grab from a real-time 4K video of a โ€œSteveโ€ aurora.

An example is in a 4K video I shot on May 6, 2018 of an usual aurora known as โ€œSTEVE.โ€

Steve Aurora – May 6, 2018 (4K) from Alan Dyer on Vimeo.


For another example of using the Sony a7III for recording real-time video of the night sky see this video of the aurora shot from Norway in March 2019.

The Northern Lights At Sea from Alan Dyer on Vimeo.


Sony a7III - Buttons and Dials

Battery Life

I found the a7III would use up about about 40% of the battery capacity in a typical 400-frame time-lapse on mild spring nights, with 30-second exposures. This is with the EVF and rear LCD Display OFF, and the camera in Airplane mode to turn off wireless functions to further conserve battery power. I was using the wired Vello intervalometer.ย 

This is excellent performance on par with the DSLRs I use. At last, we have a mirrorless camera that not only doesnโ€™t eat stars, it also does not eat batteries!ย 

One battery can get you through a night of shooting, though performance will inevitably decline in winter, as with all cameras.ย 

Planets Along the Ecliptic
MILKY WAY and PLANETS With the Sony a7III and Laowa 15mm lens at f/2 for a stack of 4 exposures for the ground to smooth noise and one exposure for the sky, all 30 seconds at ISO 3200.


Lens and Telescope Compatibilityย 

As versatile as a mirrorless camera is for lens choice, making use of that versatility requires buying the right lens adapter(s). They can cost anywhere from $100 to $400. The lowest cost units just adapt the lens mechanically; the more costly units also transfer lens data and allow auto focusing with varying degrees of compatibility.ย 

Sony a7III with MetaBones
WITH METABONES CANON ADAPTER
The MetaBones Canon EF-to-Sony E mount adapter transfers lens data and allows auto focus to function.

For use on telescopes, the simple adapters will be sufficient, and necessary as many telescope-to-camera adapters and field flatteners are optimized for the longer lens flange-to-sensor distance of a DSLR. Even if you could get a mirrorless camera to focus without a lens adapter to add the extra spacing, the image quality across the field might be compromised on many telescopes.ย 

I used the Metabones Canon-to-Sony adapter when attaching the Sony to my telescopes using my existing Canon telescope adapters. Image quality was just fine.ย 

Sony a7III with Telescope Adapter
ADAPTING TO A TELESCOPE
The MetaBones adapter, as will other brands, adds the correct lens flange to sensor distance for telescope field flatteners to work best.


Time-Lapse Controller Compatibilityย 

Due to limitations set by Sony, controlling one of their cameras with an external controller can be problematic.ย 

Devices that trigger only the shutter should be fine. That includes simple intervalometers like the Vello, the Syrp Genie Mini panning unit, and the Dynamic Perception and Rhino sliders, to name devices I use. However, all will need the right camera control cable, available from suppliers like B&H.ย 

And, as I found, the Sony might need to be placed into Continuous shooting mode to have the shutter fire with every trigger pulse from the motion controller. When used with the Genie Mini (below) the Sony fired at only every other pulse if it was in Single shot mode, an oddity of Sony’s firmware.

Some time-lapse controllers are able to connect to a camera through its USB port and then adjust the ISO and aperture as well, for ramped โ€œholy grailโ€ sunset-to-Milky Way sequences.ย 

For example, the TimeLapse+ View (see http://www.timelapseplus.com) works great for automated holy grails, but the developer recommends that with most Sonys the minimum allowed interval between shots is longer (8 to 14 seconds) than with Canons and Nikons. See http://docs.view.tl/#camera-specific-notesย 

With the Alpine Laboratories Radian2, exposure ramping is not possible with a Sony, only basic shutter triggering. See https://alpinelaboratories.com/pages/radian-2-support-get-started_sย 

Sony a7III on Genie Mini
SONY WITH THE SYRP GENIE MINI
The Sony A7III worked well with the Syrp Genie Mini motion controller with the right shutter cable but only when placed in Continuous mode.


Recommendationsย 

In conclusion, hereโ€™s my summary recommendations for the three competitive cameras, rating them from Poor, to Fair, to Good, to Excellent.ย 

Sony a7III - Angled Front

SONY: I deducted marks from the Sony a7III for deep-sky imaging for its lack of a light frame buffer, poor red sensitivity, odd LENR performance, and purple amp glow not seen on the other cameras and that dark frames did not eliminate.ย 

However, I did not consider “star eating” to be a negative factor, as theย Sony showed just as many stars and as well-resolved as did the competitors, and what more could you ask for?

I rate the Sony excellent for nightscape imaging and for real-time aurora videos. I list it as just โ€œgoodโ€ for time-lapse work only because it will not be fully compatible with some motion controllers and rampers. So beware!

Nikon D750 Angled Front

NIKON: I deducted points for real-time video of auroras โ€“ the D750 can do them but is pretty noisy with the high ISOs needed. Its red sensitivity is not bad, but its lack of a light frame buffer results a less productive imaging cycle when using LENR on deep-sky shooting.ย 

I know โ€ฆ people shoot dark frames separately for subtracting later in processing. However, Iโ€™ve found these post-shoot darks rarely work well, as the dark frames are not at the same temperature as the light frames, and often add noise or dark holes.ย 

Canon 6D MkII Angled Front

CANON: The 6D MkIIโ€™s lack of an ISO invariant sensor rears its ugly head in underexposed shadows in dark-sky nightscapes. I like its image stacking options, which can help alleviate the noise and artifacts in still images, but arenโ€™t practical for time-lapses. Thus my Good rating for nightscapes but Fair rating for time-lapses. (See my test at https://amazingsky.net/2017/08/09/testing-the-canon-6d-mark-ii-for-nightscapes/)

While the 6D MkII has HD video, it is incapable of any low-light video work.

But โ€ฆ when well exposed, such as in tracked deep-sky images, the 6D MkII performs well. (See my test at https://amazingsky.net/2017/09/07/testing-the-canon-6d-mkii-for-deep-sky/)

And its light-frame buffer is great for minimizing shooting time for a series of deep-sky images with in-camera LENR dark frames, which I find are the best for minimizing thermal noise. Give me a Canon full-frame any day for prime-focus deep-sky shooting.ย 

Itโ€™s just a pity the 6D MkII has only a 3-frame buffer when using LENR. Really Canon? The 2008-vintage 5D MkII had a 5-frame buffer! Your cameras are getting worse for astrophotography while Sonyโ€™s are getting better.ย 

SONY a7III NIKON D750 CANON 6D Mk II
Nightscapes

Excellentย 

Excellentย  Good
Time-Lapse Goodย  Excellentย  Fair
Real-Time Video (Auroras) Excellentย  Fairย  Poor
Wide-field Deep Sky Goodย  Goodย  Excellentย 
Telescopic Deep Sky Fairย  Goodย  Excellentย 

I trust you’ll find the review of value. Thanks for reading!


ADDENDUM as of JUNE 6, 2018

Since publishing the first results a number of people commented with suggestions for further testing, to check claims that:

  1. The Sony would perform better for noise under dark sky conditions, at high ISOs, rather than the moonlit scene above. OK, let’s try that.
  2. The Sony would perform better in an ISO Invariancy “face-off” if its ISOs were kept above 640, to keep all the images within the Sony’s upper ISO range of its dual-gain sensor design, with two ranges (100 to 400, and 640 on up). Fair enough.
  3. What little “star-eater” effect I saw might be mitigated by shooting on Continuous drive mode or by firing the shutter with an external timer. That’s worth a check, too.

For the additional tests, I shot all images within a 3-hour span on the night of June 5/6, using the Sony a7III, Nikon D750, and Canon 6D MkII, with the respective lenses: the Laowa 15mm lens at f/2, the Sigma 14mm Art at f/2, and the Rokinon 14mm SP at f/2.5.

The cameras were on a Star Adventurer Mini tracker to keep stars pinpoints, though the ground blurred in the longer exposures.


DARK SKY NOISE TEST

I show only the Sony and Nikon compared here, shot at the common range of ISOs used for nightscape shooting, 800 to 12800. All images are equally well exposed. The inset image at right in Photoshop shows the scene, the Milky Way above dark trees in my backyard!

To the eye, the Sony and Nikon look very similar for noise levels, just as in the moonlit scene. Both are very good โ€“ indeed, among the best performing cameras for high-ISO noise levels. But the Sony, being four years newer than the Nikon, is not better.

BUT … what the Sony did exhibit was better details in the shadows than the Nikon.

And this was with equal processing and no application of Shadow Recovery. This is where the Sony’s Backside Illuminated sensor with presumably higher quantum efficiency in gathering photons might be providing the advantage. With its good shadow details, you have to apply less shadow recovery in post-processing, which does keep noise down. So points to Sony here.

Sony vs Nikon High ISO Noise (Dark Sky)
SONY vs NIKON HIGH ISO under DARK SKIES
Noise levels appeared visually similar but the Sony showed more shadow details. Excellent!

I did put all the high ISO images through the classic noise reduction program Noise Ninja to measure total Luminance and Chrominance noise, and included the Canon 6D MkII’s images.

The resulting values and graph show the Sony actually measured worse for noise than the Nikon at each high ISO speed, 3200 to 12800, though with both performing much better than the Canon.

The higher noise of the Canon is visually obvious, but I’d say the Sony a7III and Nikon D750 are pretty equal visually for noise, despite the numbers.

Noise Ninja Value Graph
COMPARING NOISE WITH NOISE NINJA


DARK SKY ISO INVARIANCY

Again, here I show only the Sony and Nikon, the two “ISO invariant” cameras. The correct exposure for the scene was 30 seconds at ISO 6400 and f/2. The images shown here were shot at lower ISOs to underexposure the dark scene by 2 to 4 stops or EV. Those underexposed images were then boosted later in processing (in Adobe Camera Raw) by the required Exposure Value to equalize the image brightness.

Contrary to expectations, the Sony did not show any great loss in image quality as it crossed the ISO 640 boundary into its lower ISO range. But the Nikon did show more image artifacts in the “odd-numbered” ISOs of 640 and 500. In this test, the Nikon did not perform as well as the Sony for ISO invariancy. Go figure!

Again, the differences are in images vastly underexposed. And both cameras performed much better than the ISO “variant” Canon in this test.

Sony vs Nikon ISO Invariancy (Dark Sky)
DARK SKY ISO INVARIANCY
Here the Sony a7III performed well and better than the Nikon D750.


STAR EATER REVISITED

I shot images over a wide-range of exposures, from 2 seconds to 2 minutes, but show only the ones covering the 2-second to 4-second range, where the “star-eater” anti-aliasing or noise smoothing applied by Sony kicks in (above 3.2 seconds it seems).

I shot with the Sony a7III on Single shot drive mode, on Continuous Low drive mode (with the camera controlling the shutter speed in both cases), and a set with the Sony on Bulb and the shutter speed set by an external Vello intervalometer.

This is really pixel peeping at 400%. In Single drive mode, stars and noise soften ever so slightly at 4 seconds and higher. In Continuous mode, I think the effect is still there but maybe a little less. In shots on Bulb controlled by the External Timer, maybe the stars at 4 seconds are a little sharper still. But this is a tough call. To me, the star eater effect on the Sony a7III is a non-issue. It may be more serious on other Sony alphas.

Sony Star Eater-Shutter Control Series
STAR EATING vs DRIVE MODE
This series shows star sharpness in images taken in Single and Continuous drive modes, and in Externally Timed exposures.


DE-BAYERING STAR ARTIFACTS

An issue that, to me, has a more serious effect on star quality is the propensity of the Sony, and to some extent the Nikon, to render tiny stars as brightly colored points, unrealistically so. In particular, many stars look green, from the dominance of green-filtered photosites on Bayer-array sensors.

Here I compare all three cameras for this effect in two-minute tracked exposures taken with Long Exposure Noise Reduction (i.e. in-camera dark frame subtraction) off and on.

The Sony shows a lot of green stars with or without LENR. The Nikon seems to discolor stars only when LENR is applied. Why would that be? The Canon is free of any such issue โ€“ stars are naturally colored whether LENR dark frames are applied or not.

This is all with Raws developed with Adobe Camera Raw.

When opening the same Raws in other programs (ON1 Photo RAW, Affinity Photo, DxO PhotoLab, and Raw Therapee) the results can be quite different, with stars often rendered with fringes of hot, colored pixels. Or rendered with little or no color at all. Raw Therapee offers a choice of de-Bayering, or “de-mosaic,” routines, and each produces different looking stars, and none look great! Certainly not as good as the Canon rendered with Camera Raw.

What’s going on here is a mystery โ€“ it’s a combination of the cameras’ unique Raw file formats, anti-alias filter in front of the sensor (or lack thereof in the Sony), and the de-Bayering routines of all the many Raw developers wrestling with the task of rendering stars that occupy only a few pixels. It’s unfair to blame just the hardware or the software.

But this test re-emphasized my thoughts that Canon DSLRs remain the best for long-exposure deep-sky imaging where you can give images as much exposure time as they need, while the ISO invariant Sony and Nikons exceed at nightscape shooting where exposures are often limited and plagued by dark shadows and noise.

Sony vs Nikon vs Canon-LENR Off and On
COLORED STARS COMPARISON
The Sony shows a propensity to render small stars in many vivid and unreal colors. The Nikon can do so after LENR is applied. The Canon is more neutral and natural.

So the pixel-peeping continues!

I hope you found these latest tests of interest.

โ€” Alan, May 31, 2018 / Revised June 6, 2018, March 27, 2019 and March 27, 2021 / ยฉ 2018 Alan Dyer / AmazingSky.com

Free 2017 Amazing Sky Calendar


2017-sky-calendar-cover

My free Amazing Sky Calendar for 2017 is now available for download! Plan your astronomical year!

Once again, I have prepared a free 12-month Calendar listing loads of celestial events, Moon phases, highlighted space events, and with small charts to show what’s happening in the sky for the coming year. Plus a set of my favourite images from 2016.

You can download it as a 26-megabyte PDF at my website atย http://www.amazingsky.com/about-alan.html

Scroll down the page for the button link.

You can print the Calendarย out as you wish for your personal use.

Do share and tell others about the Calendar, but please send them to my page for them to download the file themselves.

Thanks, and here’s toย a great celestial 2017!

โ€” Alan, November 18, 2016 / ยฉ 2016 Alan Dyer / amazingsky.com

 

Free 2016 Sky Calendar


2016 Calendar Cover

Plan your cosmic year with my free 2016 Sky Calendar.

My Calendar lists all the best sky events for 2016, plus Moon phases, to help you plan your astronomical year.

Coming up we have:

โ€ข A fairly close approach of Mars

โ€ข A rare transit of Mercury

โ€ข A photogenic gathering of Mars, Saturn and Antares

… among many other sky events.

You can download the free PDF at

http://www.amazingsky.com/about-alan.html

Feel free to share the link to this page.

Happy New Year to all!

โ€” Alan, December 29, 2015 / ยฉ 2015 Alan Dyer

10 Tips for Terrific Time-Lapses


eMotimo at Dino Park #1

Here are my top tips for shootingย terrificย still-image nightscapes … and time-lapse movies of the night sky.ย 

Canon 6D

1. Go for pixel size, not pixel count

When choosing a camera for night sky scenes, the most important characteristic is not number of megapixels. Just the opposite.

The best cameras are usually models with more modest megapixel counts. Each of their individual pixels is larger and so collects more photons in a given exposure time, yielding higher a signal-to-noise ratio โ€“ or lower noise, critical for night shooting.

Cameras with pixels (the โ€œpixel pitchโ€) 6 to 8 microns across are best. Many high-megapixel cameras have tiny 4-micron pixels.

Large-pixel cameras are often the full-frame models, such as the Canon 5D MkIII and 6D, the Nikon D610, D750, and Df, and the Sony a7s and a7S II.

Many โ€œcropped-frameโ€ cameras are now 18- to 24-megapixel models with smaller, noise-prone pixels. They can certainly be used, but will requireย more care in exposing well at lower ISOs, and in processing to smooth out noise without blurring detail.

Manual Settings

2. Learn to fly on manual

While DSLRs and Compact System Cameras have amazing automatic functions we use none of them at night.

Instead, we use the camera on Manual or Bulb, dialling in shutter speed, aperture and ISO speed manually. We also have to focus manually, using Live View mode to focus on a bright star or distant light.

Learn the tradeoffs involved: Increasing ISO sensitivity of the sensor keeps exposure times down but increases noise. Opening up the lens aperture to f/2 or f/1.4 also keeps exposures short but introduces image-blurring aberrations, especially at the frame corners.

To prevent stars from trailing due to the skyโ€™s motion adhere to the โ€œ500 Rule:โ€ the maximum exposure time is roughly 500 divided by the focal length of your lens.

Histogram-Correct

3. Expose to the rightย 

At night, always give the sensor plenty of signal.

Use whatever combination of shutter speed, aperture and ISO will provide a well-exposed image. The image โ€œhistogram,โ€ the graph of number of pixels at each brightness level shown above, should never be slammed to the left.

It should be a well-distributed โ€œmountain rangeโ€ of pixels, extending well to the right. If the 500 Rule restricts your shutter speed, and your desire for sharp images across the frame demands you shoot at f/2.8 or even slower, then donโ€™t be afraid to bump up the ISO speed to whatever it takes to produce a good histogram and a well-exposed image.

Noise will look far worse if you underexpose, then try to boost the image brightness later in processing. Expose to the right!

File Format #2 7D

4. Shoot Raw!

Shoot Raw. Period.

When comparing Raw and compressed JPG versions of the same image, you can be fooled into thinking the JPGs look better (i.e. smoother) because of the noise reduction the camera has applied to the JPG that is beyond your control. However, that smoothing has also wiped out fine detail, like stars.

By shooting Raw you get to control whatever level of noise reduction and sharpening the image needs later in processing.

JPGs are also 8-bit images with a limited tonal range โ€“ย or palette โ€“ย in which to record the subtle gradations of brightness and colour present in our images.

Imported Raw files are 16-bit, with a much wider tonal scale and colour palette. Thatโ€™s critical for all astrophotos when, even with a well-exposed image, many tonal values are down in the dark end of the range. Processing Raw images makes it possible to extract detail in the shadows and highlights.

Even when shooting a time-lapse sequence, shoot Raw.

LENR

5. Take dark frames (sometimes!)

LENR reduces noise.

Itโ€™s a topic of some debate, but in my experience it is always better to turn on the cameraโ€™s Long Exposure Noise Reduction (LENR) function when shooting individual nightscape images. Doing so forces the camera to take a โ€œdark frame,โ€ an exposure of equal length but with the shutter closed.

It records just the noise, which the camera then subtracts from the image. Yes, it takes twice as long to acquire an image, but the image is cleaner, with fewer noisy pixels.

This is especially true when shooting on hot summer nights (the warmer the sensor the higher the noise). That said, you cannot use LENR when shooting frames for star trail composites or time-lapse movies.

For those, the interval between images should be no more than 1 to 5 seconds. Using LENR would introduce unsightly gaps in the trails or jumps in the star motion in time-lapses.

As an alternative, it is possible to take separate dark frames at the end of the night by simply covering the lens and taking exposures of the same duration and at the same ISO as your “light frames.”

Some stacking software, such as StarStax and the Advanced Stacker Actions have places to put these dark frames, to subtract them from the stack later in processing.

811eBU4sBkL._SL1500_

6. Use fast lenses

A fast lens is your best accessory.

While the โ€œkit zoomโ€ lenses that come with many DSLRs are great for shooting bright twilight or Full Moon scenes, they will prove too slow for dark starlit scenes with the Milky Way.

In addition to exposing to the right and shooting Raw, the secret to great nightscapes is to shoot with fast lenses, usually โ€œprimeโ€ lenses with fixed focal lengths. They are usually faster and have better image quality than zooms.

Your most-used lens for nightscape and time-lapse shooting is likely to be a 14mm to 24mm f/2 to f/2.8 lens.

Fortunately, because we donโ€™t need (and indeed canโ€™t use) autofocus we can live happily with low-cost manual lenses, such as the models made in Korea and sold under brands such as Rokinon, Samyang and Bower. They work very well.

The quarter Moon reflected in the waters of Reesor Lake, Alberta in Cypress Hills Interprovincial Park. Taken on July 5, 2014. This is with the 14mm Rokinon lens and Canon 6D at ISO800. This is a high dynamic range stack of6 exposures from 1/15 to 0.6 seconds taken just before using the camera to take a motion control time-lapse. The Moon was in conjunction with Mars (right of Moon) and Spica (left of Moon) but in the bright twilight they are not showing up here.

7. Get to know the Moon & Milky Way

For many nightscape and time-lapse shoots, the Moon is your light source for illuminating the landscape.

When the Moon is absent, the Milky Way is often your main sky subject.

Knowing where the Moon will be in the sky at its various phases, and when it will rise (in its waning phases after Full Moon) or set (in its waxing phases before Full) helps you a plan a shoot, so youโ€™ll know whether a landscape will be well lit.

Astronomy apps for desktop computers and mobile devices are essential planning aids. A good one specifically for photographers is The Photographer’s Ephemeris.

Knowing in what season and time of night the Milky Way will be visible is essential if you want to capture it. Donโ€™t try for Milky Way shots in spring โ€“ it isn’t up!

Me with cameras shooting time-lapses at Crawling Lake reservoir, Alberta, June 30/July 1, 2013. Perpetual twilight of summer solstice shines to the north and very weak noctilucent clouds.

8. Keep it simple to start

Don’t be seduced by the fancy gear.ย 

Time-lapse imaging has blossomed into a field replete with incredible gear for moving a camera incrementally during a shoot, and for automating a shoot as day turns to night.

I explain how to use all the fancy gear in my ebook, linked to below, however … Great time-lapses, and certainly still-frame nightscapes, can be taken with no more than a DSLR camera with a good fast lens and mounted on a sturdy tripod. Invest in the lens and donโ€™t scrimp on the tripod.

Another essential for shooting multi-frame star trails and time-lapses is a hardware intervalometer ($50 to $150).

TC-80N3 Masked

9. Learn the intricacies of intervals

For time-lapses, an intervalometer is essential.

Mastering exposure and focus in still images is essential for great time-lapse movies because they are simply made of hundreds of well-exposed still frames.

But move to time-lapses and you have additional factors to consider: how many frames to shoot and how often to shoot them. A good rule of thumb is to shoot 200ย to 300 frames per sequence, shot with an interval of no more than 1 to 5 seconds between exposures, at least for starry night sequences.

However, most intervalometers (the Canon TC-80N3 is an exception) define their โ€œIntervalโ€ setting to mean the time from when the shutter opens to when it opens again. In that case, you set the Interval to be a value 1 to 5 seconds longer than the exposure time you are using. That’s also true of theย intervalometer function Nikon builds into their internal camera firmware.

Test first!

The summer Milky Way with a meteor streaking at centre as a bonus. An aurora to the north off frame is lighting the foreground with a green glow. Haze and forest fire smoke obscure the horizon. I shot this at the Battle Scene viewpoint at Writing-on-Stone Provincial Park, in southern Alberta. Sagittarius and the galactic centre is on the horizon at left of centre. Capricornus is amid the haze at left of centre. On the horizon are the Sweetgrass Hills in Montana. The Milk River winds below amid the sandstone formations that are home to historic First Nations petroglyphs.  This is a single 30-second exposure with the Nikon D750 at ISO 3200 and Sigma 24mm Art lens at f/2, taken as part of a time-lapse sequence.

10. Go to beautiful places

While the gear can be simple, great shots demandย anย investment in time.

By all means practice at home and at nearby sites that are quick to get to. Try out gear and techniques at Full Moon when exposures are short (the Full Moon is bright!) and you can see what you are doing.

But beautiful images of landscapes lit by moonlight or starlight require you to travel to beautiful locations.

When you are on site, take the time to frame the scene well, just as you would during the day. Darkness is no excuse for poor composition!

While shooting nightscapes and time-lapses can be done with a minimal investment in hardware and software, it does require an investment in time โ€“ time to travel and spend nights shooting at wonderful places under the stars.

Enjoy the night!

I cover all these topics, and much more, in detail in my ebook How to Photograph & Process Nightscapes and Time-Lapses. Click the link below to learn more.

โ€” Alan, September 16, 2015 / ยฉ 2015 Alan Dyer / www.AmazingSky.com

Canon vs. Nikon for Astrophotography


Canon and Nikon Cameras

I’ve been an avowed Canon DSLR user for a decade. I may be ready to switch!

[NOTE: This review dates from 2015. Tests done today with current models would certainly differ. Canon’s EOS R mirrorless series, for example, offer much better ISO Invariancy performance but lack the “dark frame buffer” advantage of Canon DSLRs. And indeed, I have used the Nikon D750 a lot since 2015. But I did not give up my Canons!]

Here, in a technical blog, I present my tests of two leading contenders for the best DSLR camera for nightscape and astronomical photography: the Canon 6D vs. the Nikon D750. Which is better?

To answer, I subjected both to side-by-sideย outdoor tests, using exposures you’ll actually use in the field for typical nightscapes and for deep-sky images.

Both cameras are stock, off-the-shelf models. They haveย notย had their filters modified for astronomy use.ย Both are 20- to 24-megapixel, full-frame cameras, roughly competitive in price ($1,900 to $2,300).

For images shot through lenses, I used the Canon L-Series 24mm on the Canon 6D, and the Sigma 24mm Art lens on the Nikon D750.

The bottom line:ย Both are great cameras, with the Nikon D750 having the edge for nightscape work, and the Canon 6D the edge for deep-sky exposures.

NOTE: Click on the test images for higher-resolution versions for closer inspection. All images and text ยฉ 2015 Alan Dyer and may not be reproduced without my permission.


TEST #1 โ€” Noise

The 24.3-megapixel Nikon D750 has 5.9-micron pixels, while the 20.2-megapixel Canon 6D has slightly larger 6.5-micron pixels which, in theory, should lead to lower noise for the Canon. How do they compare in practice?

The scene used to test for noise (here with the Nikon images) showing the development settings applied to both the Nikon and Canon sets. NO noise reduction (colour or lunminance) was applied to any of the images, but Exposure, Shadows, Contrast and Clarity were boosted, and Highlights reduced.
The scene used to test for noise (here with the Nikon images) showing the development settings applied to both the Nikon and Canon sets. NO noise reduction (colour or lunminance) was applied to any of the images, but Exposure, Shadows, Contrast and Clarity were boosted, and Highlights reduced.

I shot aย moonlit nightscape scene (above) at five ISO settings, from 800 to 12800, at increasingly shorter exposures to yield identically exposed frames. I processed each frame as shown above, with boosts to shadows, clarity, and contrast typical for nightscapes. However, I applied no noise reduction (either luminance or color) in processing. Nor did I take and apply dark frames.

Noise - Canon

Noise - Nikon

The blowups of aย small section of the frame (outlined in the box in the upperย right of the Photoshop screen) show very similar levels of luminance noise. The Canon shows slightly more color noise, in particular more magenta pixels in the shadows at high ISOs. Its larger pixels didn’t provide the expected noise benefit.


TEST #2 โ€” Resolution

Much has been written about the merits of Canonย vs. Nikon re: the most rigorous of tests, resolving stars down at the pixel level.

I shot the images below of the Andromeda Galaxy the same night through a 92mm aperture apo refractor. They have had minimal but equal levels of processing applied. At this level of inspection the cameras look identical.

M31 (Canon 6D)

M31 (Nikon D750)

But what if we zoom in?

For many years Nikon DSLRs had a reputation for not being a suitable for stellar photography because of a built-in noise smoothing that affected even Raw files, eliminating tiny stars along with noise. Raw files weren’t raw. Owners worked around this by turning on Long Exposure Noise Reduction, then when LENR kicked in after an exposure, they would manually turn off the camera power.

This so-called “Mode 3” operation yielded a raw frame without the noise smoothing applied. Clearly, this clumsy workaround made it impossible to automate the acquisition of raw image sequences with Nikons.

Are Nikons still handicapped? In examining deep-sky images at the pixel-peeping level (below), I saw absolutely no difference in resolution or the ability to record tiny and faint stars. With its 4-megapixel advantage the Nikon should resolve finer details and smaller stars, but in practice I saw little difference.

Closeup of telescope view of Andromeda Galaxy with Canon 6D 4 minute exposure at ISO 800 No noise reduction applied in processing
Closeup of telescope view of Andromeda Galaxy with Canon 6D
4 minute exposure at ISO 800
No noise reduction applied in processing

Closeup of telescope view of Andromeda Galaxy with Nikon D750 4 minute exposure at ISO 800 No noise reduction applied in processing
Closeup of telescope view of Andromeda Galaxy with Nikon D750
4 minute exposure at ISO 800
No noise reduction applied in processing

On the other hand I saw no evidence for Nikon’s “star eater” reputation. I think it is time to lay this bugbear of Nikons to rest. The Nikon D750 proved to beย just as sharp as the Canon 6D.

Note that in the closeups above, the red area marks a highlight (the galaxy core) that is overexposed and clipped. Nikon DSLRs also have a reputation for having sensors with a larger dynamic range than Canon, allowing better recording of highlights before clipping sets in.

However, in practice I saw very little difference in dynamic range between the two cameras. Both clipped at the same points and to the same degree.


TEST #3 โ€” Mirror Box Shadowing

An issue little known outside of astrophotography is that a DSLR’s deeply-inset sensor can be shadowed by the upraised mirror and sides of the mirror box. Less light falls on the edges of the sensor.

The vignetting effect is noticeable only when we boost the contrast to the high degree demanded by deep-sky images, and when shooting through fast telescope systems.

Here I show the vignetting of the Canon and Nikon when shooting through my 92mm refractor at f/4.5.

The circular corner vignetting visible in the images below is from the field flattener/reducer I employed on the telescope. It can be compensated for by using Lens Correction in Adobe Camera Raw, or eliminated by taking flat fields.

Demonstrating the level of vignetting and mirror-box shadowing with the Canon 6D on a TMB 92mm apo refractor with a 0,85x field flattener/reducer lens
Demonstrating the level of vignetting and mirror-box shadowing with the Canon 6D on a TMB 92mm apo refractor with a 0.85x field flattener/reducer lens

Demonstrating the level of vignetting and mirror-box shadowing with the Nikon D750 on a TMB 92mm apo refractor with a 0,85x field flattener/reducer lens
Demonstrating the level of vignetting and mirror-box shadowing with the Nikon D750 on a TMB 92mm apo refractor with a 0.85x field flattener/reducer lens

The dark edge at the bottom of the frame is from shadowing by the upraised mirror. It can be eliminated only by taking flat fields, or reduced by using masked brightness adjustments in processing.

Both cameras showed similar levels of vignetting, with the Canon perhaps having the slight edge.


TEST #4 โ€” ISO Invariancy

So far the Nikon D750 and Canon 6D are coming up fairly equal in performance. But not here. This is where the Nikon outperformsย the Canon by quite a wide margin.

Sony sensors (used in Sony cameras and also used by Nikon) have a reputation for being “ISO Invariant.”

What does that mean?

A typical Milky Way nightscape with the Nikon D750 and Sigma 24mm Art lens. With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances. Lens correction and basic development setttings applied.
A typical Milky Way nightscape with the Nikon D750 and Sigma 24mm Art lens.
With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances.
Lens correction and basic development setttings applied.

A typical Milky Way nightscape with the Canon 6D and Canon 24mm L lens (original model). With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances. Lens correction and basic development setttings applied.
A typical Milky Way nightscape with the Canon 6D and Canon 24mm L lens (original model).
With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances.
Lens correction and basic development setttings applied.

In the examples above, the correct exposure for the starlit scene was 15 seconds at f/1.4 at ISO 6400. See how the two cameras rendered the scene? Very similar, albeit with the Canon showing more noise and discoloration in the dark frame corners.

What if we shoot at the same 15 seconds at f/1.4 … but at ISO 3200, 1600, 800, and 400? These are now 1-, 2-, 3-, and 4-stops underexposed, respectively.

Then we boost the Exposure setting of the underexposed Raw files later in processing, by 1, 2, 3 or 4 f-stops. What do we see?

Nikon D750 - Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)
Nikon D750 – Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)

With the Nikon (above) we see images that look nearly identical for noise to what we got with the properly exposed ISO 6400 original. It really didn’t matter what ISO speed the image was shot at โ€“ย we can turn it into any ISO we want later with little penalty.

Canon 6D - Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)
Canon 6D – Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)

With the Canon (above) we get images with grossly worse noise in the shadows and with ugly magenta discoloration. Canons cannot be underexposed. You must use as high an ISO as needed for the correct exposure.

This “ISO Invariant” advantage of Nikon over Canon is especially noticeable in nightscapes scenes lit only by starlight, as above. The Canon turns ugly purple at -3EV underexposure, and loses all detail and contrast at -4EV underexposure.

For nightscape imaging this is an important consideration. We are limited in exposure time and aperture, and so are often working at the ragged edge of exposure. Dark areas of a scene are often underexposed and prone to noise. With the Nikon D750 these areas may still look noisy, but not much more so than they would be at that ISO speed.

With the Canon 6D, underexpose the shadows and you pay the price of increased noise and discoloration when you try to recover details in the shadows.

ย For more technical information on the topic of ISO invariancy, see DPReview.com and many of their recent reviews of DSLRs, such as this page about the Canon 5Ds/r models.ย 

Apparently, the difference comes from where the manufacturer places the analog-to-digital circuitry: on the sensor (ISO invariant) or outboard on a separate circuit (ISO variant), and thus where in the signal path the amplification occurs when we boost ISO speed.


TEST #6 โ€” Features

One could go on endlessly about features, but here I compare the two cameras on just a few key operating features very important to astrophotographers.

Nikon Intervalometer Start

Intervalometer:

The Canon 6D has none, though newer Canons do. The Nikon D750, as do many Nikons, has a built-in intervalometer (shown above), even with a deflickering “Exposure Smoothing” option. However, exposure time is limited to the camera’s maximum of 30 seconds. Any longer requires an outboard intervalometer, as with the Canon.

If you use your camera with any motion control time-lapse unit, then it becomes the intervalometer, negating any capability built into the camera. But it’s nice to have.

Small Advantage: Nikon


Interval Length:

REVISED JUNE 2020:

When taking time-lapse or star trail images with the Canon I can set an interval as short as 1 second between frames, for a minimum of gaps or jumps in the stars. With the Nikon, controlled internally by its built-in intervalometer, a 1-second interval is possible but only if you set the interval to 33 seconds for a 30-second shutter speed.

That’s true of Canon and Sony built-in intervalometers as well, because on all cameras setting the exposure to 30 seconds really gives you a 32-second exposure. A little known fact! So the interval between shutter firings has to be set to 33 seconds. It’s tricky.

Advantage: None to either


Nikon D750 with Radian

Tiltable LCD Screen:

The Canon 6D has none. The Nikon D750 has a very useful tilt-out screen as shown above. This is hugely convenient for all forms of astrophotography. Only cropped-frame Canons have tilt-out screens. This feature might add weight, but it’s worth it!

Big Advantage: Nikon


Dark Frame Buffer:

The Nikon has none. With Long Exposure Noise Reduction ON, the Canon 6D allows up to four exposures to be shot in quick succession before the dark frame kicks in and locks up the camera. (Put the camera into Raw+JPG.)

[JUNE 2020: With the Canon 6D MkII the buffer allows three frames to be taken in quick succession.]

This is very useful for deep-sky imaging, for acquiring a set of images for stacking that have each had a dark frame subtracted in-camera, with a minimum of “down-time” at the camera.

Big Advantage: Canon


Live View Screen Brightness:

As pointed out to me by colleague Christoph Malin, with the Nikon you cannot dim the screen when in Live View mode and with Exposure Simulation ON. So it can be too bright at night. With the Canon you can dim the Live View screen โ€” the LCD Brightness control affects the screen both during Live View as well as duringย playback of images.

Small Advantage: Canon


Canon with GBTimelapse

Software Compatibility:

Canon EOS cameras are well supported by advanced software, such as GBTimelapse (above) that controls only Canons, not Nikons, in complex time-lapse sequences, and Nebulosity, popular among deep-sky imagers for DSLR control.

Small Advantage: Canon


Myย take-away conclusions:ย 

โ€ข Nikon DSLRs now are just as good for astrophotography as Canons, though that wasn’t always the case โ€“ย early models did suffer from more noise and image artifacts than their Canon counterparts.

โ€ข Canon DSLRs, due to their sensor design, are more prone to exhibiting noise and image artifacts when images are greatly underexposed then boosted later in processing. Just don’t underexpose them – good advice for any camera.


All images and text are ยฉ 2015 Alan Dyer.

โ€“ Alan, August 27, 2015 & Revised June 25, 2020 / ยฉ 2015 Alan Dyer / www.amazingsky.com

How to See & Shoot the Perseids


A trio of Perseid meteors shoot at left in the pre-dawn sky over Lake Minnewanka in Banff National Park. The overexposed waning crescent Moon shines between Venus (below) and Jupiter (above), with Jupiter near the Hyades and below the Pleiades in Taurus. Taken the morning of Sunday, August 12, 2012 with the Canon 5D MkII and 24mm Canon L-series lens. This is a composite of three exposures, one for each meteor, each for 40 seconds at ISO 2000 and f/5. Landscape is from one image, two other meteors from two other frames layered in and registered in the correct position in the base layer.

It’s Perseidย meteor shower time. Here are tips for seeing and shooting the meteors.

What are the Perseids?

They are an annual meteor shower, perhaps the most widely observed of the year, that peak every year about August 12. They are caused by Earth passing through a dust stream left by Comet Swift-Tuttle, last seen near Earth in 1992.

Each “shooting star” is really a bit of comet dust burning up in our atmosphere as it ploughs into us at 200,000 kilometres an hour. They don’t stand a chance ofย surviving โ€“ and none do.

All Perseid particles burn up. None reach Earth.

Perseid meteor caught night of August 12-13 2009 from Cypress Hills Prov Park in Saskatchewan at the annual Saskatchewan Summer Star Party. One frame of 250 shot as part of a time-lapse movie. Taken with Canon 5D MkII and 24mm lens at f/2.5 for 30s at ISO1600.
Perseid meteor caught night of August 12-13 2009 from Cypress Hills Prov Park in Saskatchewan at the annual Saskatchewan Summer Star Party. One frame of 250 shot as part of a time-lapse movie. Taken with Canon 5D MkII and 24mm lens at f/2.5 for 30s at ISO1600.

When are the Perseids?

The peak night of the Perseids this year is the night of Wednesday, August 12 into the early morning hours of August 13, with the peak hour occurring about midnight Mountain Daylight Time or 2 a.m. on the 13th for Eastern Daylight Time.

For North America, this is ideal timing for a good show this year. However, a good number of meteors will be visible the night before and night after peak night.

Even better, the Moonย is near New and so won’t interfere with the viewing by lighting up the sky.

In all, exceptย for the mid-week timing, conditions this year in 2015 couldn’t be better!

Perseid meteor caught night of August 12-13 2009 from Cypress Hills Prov Park in Saskatchewan at the annual Saskatchewan Summer Star Party. One frame of 260 shot as part of a time-lapse movie. Taken with Canon 20Da and 15mm lens at f/2.8 for 45s at ISO1600.
Perseid meteor caught night of August 12-13 2009 from Cypress Hills Prov Park in Saskatchewan at the annual Saskatchewan Summer Star Party. One frame of 260 shot as part of a time-lapse movie. Taken with Canon 20Da and 15mm lens at f/2.8 for 45s at ISO1600.

What do they look like?

Any meteor looks like a brief streak of light shooting across the sky. The brightest will outshine the brightest stars and are sure to evoke a “wow!” reaction.

However, the spectacular Perseids are the least frequent. From a dark site, expect to see about 40 to 80 meteors in an hour of patient and observant watching, but of those, only a handful โ€“ perhaps only 1 or 2 โ€“ will be “wow!” meteors.

A pair of Perseid meteors shoot at left in the late night sky at the Upper Bankhead parking lot in Banff National Park. The  waning crescent Moon is just rising above the trees. A faint Perseid is at right, while a satellite trail goes from left to right as well.  Taken the night of Saturday, August 11 into the wee hours of Sunday, August 12, 2012 with the Canon 7D and 10-22mm Canon lens. This is a stack of two exposures, one for each meteor, each for 60 seconds at ISO 1250 and f/4. The stars are trailed slightly due to the two-minute exposure time in total.
A pair of Perseid meteors shoot at left in the late night sky at the Upper Bankhead parking lot in Banff National Park. The waning crescent Moon is just rising above the trees.ย 
Taken the night of Saturday, August 11 into the wee hours of Sunday, August 12, 2012 with the Canon 7D and 10-22mm Canon lens. This is a stack of two exposures, one for each meteor, each for 60 seconds at ISO 1250 and f/4.ย 

Where do I look?

All the meteors will appear to radiate from a point in the constellation of Perseus in the northeastern sky in the early hours of the night, climbing to high overhead by dawn.

So you can face that direction if you wish, but Perseids can appear anywhere in the sky, with the longest meteor trails often opposite the radiant point, over in the southwest.

Shows unusual Perseid meteor varying in brightness? Or is this a satellite that mimics Perseid for position (it comes right out of the radiant point).  Taken at SSSP, August 14, 2010, using Canon 5D MkII and 15mm lens.
Shows unusual Perseid meteor varying in brightness? Or is this a satellite that mimics Perseid for position (it comes right out of the radiant point).ย Taken at Saskatchewan Star Party, August 14, 2010, using Canon 5D MkII and 15mm lens.

How do I look?

Simple โ€“ just lie back on a comfy lawn chair or patch of grass and look up!

But … you need to be at a dark location away from city lights to see the most meteors. You’ll see very little in a city or light-polluted suburbs.

Head to a site as far from city lights as you can, to wherever you’ll be safe and comfortable.

How do I take pictures?

To stand any chance of capturing these brief meteors you’ll need a good low-noise camera (a DSLR or Compact System Camera) with a fast (f/2.8 or faster) wide-angle lens (10mm to 24mm).

Sorry, keep your point-and-shoot camera and phone cameraย tucked away in your pocket โ€“ they won’t work.

Set up you camera on a tripod, open the lens to f/2.8 (wide open perhaps) and the ISO to 800 to 3200) and take a test exposure of 20 to 40 seconds. You want a well-exposed image but not over-exposed so the sky is washed out.

Set your exposure time accordingly โ€“ most cameras allow a maximum exposure of 30 seconds. Exposuresย longer than 30 seconds require a separate intervalometer to set the exposure, with the camera set on Bulb (B).

Take lots of pictures!

To up your chances of catching a meteor, youย need to set the camera to shoot lots of frames in rapid succession.

Use an intervalometer to take shots one after the other with as little time between as possible โ€“ because that’s when a meteor will appear!

Barring an intervalometer, if you have standard switch remote control, set the camera on High Speed Continuous, and the shutter speed to 30 seconds, then lock the remote’s switch to ON to keep the camera firing. As soon as one exposure ends it’ll fire another.

Twin Perseids in this photo? Or are these satellites?  Taken at SSSP, August 14, 2010, using Canon 5D MkII and 15mm lens.
Twin Perseids in this photo? Or are these satellites?ย Taken at SSSP, August 14, 2010, using Canon 5D MkII and 15mm lens.

What else do I need to know?

โ€ข Focus the lens carefully so the stars are sharp โ€“ the Live Focus mode helps for this. Focus on a bright star or distant light.

โ€ข Aim the camera to take in a wide swath of the sky but include a well-composed foreground for the most attractive shot.

โ€ข Aim northeast to capture meteors streaking away from the radiant. But you can aim the camera to any direction that lends itself to a good composition and still capture a meteor.

โ€ข To increase your chances, shoot with two or more cameras aimed to different areas of the sky. Meteors always appear where your camera isn’t aimed!

โ€ข Be patient! Despite shooting hundreds of frames only a handful will record a meteor, as only the brightest will show up.

Can I track the sky?

If you have a motorized equatorial mount or a dedicated sky tracking device (the iOptron Sky Tracker and Sky-Watcher Star Adventurer, each about $400, are popular), you can follow the stars while taking lots of shots. This avoids the stars trailing and allows you to use longer exposures.

The video above shows a Star Adventurer tracking the sky as it turns about its polar axis which is aimed up to a point near Polaris. Click the Enlarge and HD buttons to view the videoย properly.

Polar align the tracker, but then perhaps aim the camera to frame the summer Milky Way overhead. Take lots of 1-ย to 3-minute exposures, again at f/2.8 and ISO 800 to 1600. Some exposures will pick up meteors โ€“ with luck!

Tracking then stacking

Later, in processing, because the sky has remained fixed on the frame, it’s then possible to stack the images (using aย “Lighten” blend mode on each image layer) so that the final composite frame contains more meteors, for an image with lots of meteors captured over an hour or more of shooting.

While it is possible to stack shots taken on a static tripod to produce such a meteor composite, doing so requires a lot of manual cutting, pasting and aligning of meteor images by hand. The result is a bit of a fake, though I’ve done it myself โ€“ the image at top is an example, though with only a trioย of meteors.

Good luck and happy meteor watching!

โ€“ Alan, August 6, 2015 / ยฉ 2015 Alan Dyer / www.amazingsky.comย 

Heads Up! Sight the Thin Moon by Mercury & Venus


Jan 21 Planets

On Wednesday, January 21 look low in the southwest for a conjunction of the Moon and inner planets.

Mercury is ending its brief evening appearance and proximity to Venus. But this week you can still spot it a binocular field or so below Venus as it descends back toward the Sun.

On Wednesday, January 21, look low in the southwest to sight the thin waxing crescent Moon sitting near Venus and Mercury, forming a wide triangle of inner rocky worlds.

The other rocky planet in the inner solar system, Mars, shines higher up in the evening twilight as a moderate brightness reddish star. The next night, January 22, the waxing Moon will sit beside Mars in a wide conjunction.

Catch the Moon-Mercury-Venus trio early, as they will set an hour or so after local sunset.

Clear skies!

โ€“ Alan, January 19, 2015 / ยฉ 2015 Alan Dyer / www.amazingsky.com

Marvelling at the Milky Way


RAO Milky Way Night Panorama

Peopleย gather at a rural observatory to gaze at the Milky Way on a summer night.

The clouds drifted through now and then but skies were mostly clear for the last of the Rothney Astrophysical Observatory‘s annual Milky Way Nights for 2014.

A tradition since 2009 and the Year of Astronomy, these dark-of-the-moon nights at the Observatory have proven hugely popular each summer despite the 10 p.m. start and 2 a.m. finish!

The main image at top shows a 360ยฐ panorama as people were gathering at the portable telescopes and lining up โ€“ in a blur โ€“ for a look inside the observatory domes.

RAO Milky Way Night #1 (Aug 30, 2014)

Roland from the Royal Astronomical Society of Canada provided laser-guided star tours. How did we point out the stars and constellations before green lasers? In the hands of responsible astronomers they are a great tool for public education.

RAO Milky Way Night #4 (Aug 30, 2014)

Here he’s pointing out Vega and the stars of the Summer Triangle. Look way up!

About 400 people attended on Saturday night, the last in a trio of nights this past week. As you can see, the event attracts people of all ages. It’s even a popular date night attraction.

RAO Milky Way Night #6 (Aig 30, 2014)

At these summer stargazing sessions many people bring blankets to just lie back and look up, at a site away from the ugly glow of the city, here lighting up the clouds to the north.

It was a great night of public stargazing!

โ€“ Alan, August 31, 2014 / ยฉ 2014 Alan Dyer

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