nebulas – The Amazing Sky

January 24, 2025January 25, 2025

Deep-Sky Hunting in the Other Galaxy Season

Amateur astronomers soon learn that spring is “galaxy season.” But so is autumn … if you know where to look.

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 — though, as shown in this artwork based on data from the European Space Agency’s recently concluded Gaia mission, that disk is warped.

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 — and from the southern hemisphere — 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 32º 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.

Galaxies Galore!

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 1/2º across (as wide as a Full Moon diameter — the field here is 2º by 3º). 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 (1/2º 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 1.6º by 2.4º.) 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,
– and the barred spiral galaxy NGC 1365 at lower right, considered one of the best barred spirals in the sky. 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.

Bonus Nebulas!

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 1/4º 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.

About the Images

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.

— Alan, January 24, 2025 / AmazingSky.com

November 25, 2023November 25, 2023

Exploring the Dusty Realms of the Milky Way

A run of exceptionally clear nights allowed me to capture scenes of stardust along the MilkyWay.

Colourful nebulas – clouds of glowing gas – are the most popular targets in the deep sky for astrophotographers. Most nebulas emit red light from hydrogen atoms. Some glow blue by reflecting the light of nearby hot stars.

But another class of nebulas emits or reflects almost no light, and appears dark, often as shapes silhouetted against the bright starry background. They are usually made of obscuring interstellar dust – typically grains of carbon soot emitted by aging or active stars – literally stardust.

In the olden days of film photography, these dark dust clouds always appeared black in our exposures. Or they never showed up at all.

But today’s digital cameras, with the aid of processing techniques, can capture the dust clouds, often not as black clouds, but as pale blue tendrils, or as brownish-yellow streamers faintly glowing with a warm light.

In October and November 2023, a series of unusually clear and mild nights allowed me to go after some of these dark and dusty targets, from my home in rural southern Alberta, Canada. I captured a selection of scenes off the beaten track along the Milky Way. Here’s my tour of stardust sights in the northern autumn and winter sky.

Cepheus the King

The wide-field image above frames most of the northern constellation of Cepheus. The southern section of Cepheus at the bottom of the frame lies in the Milky Way and is rich in bright red nebulas, notably the large, round IC 1396. It is a popular and easy target. But the northern upper reaches of Cepheus are where more challenging dusty nebulas reside. I’ve indicated the location of two fields shown in the close-ups below.

The Iris Nebula

Located some 1300 light years away, this is a blue reflection nebula, as the dust is lit by the young blue star in its core. But surrounding the bright Iris Nebula are more extensive clouds of dust, dimly lit by reflected light and with varying densities and shades of grey and brown.

The Dark Shark and Wolf’s Cave Nebulas

This is a portrait of a field of dusty nebulas in northern Cepheus, in a stack of 30 x 6-minute exposures with the Astro-Tech AT90CFT refractor at f/4.8 and filter-modified Canon EOS R camera at ISO 800, though no filter was used when taking these frames.

This field in northern Cepheus is yellowed by reams of dust. A couple of blue reflection nebulas lie on the edges of streamers of brown dust. The object at top is called the Dark Shark, for its fanciful resemblance to a menacing shark, though one wearing a blue hat!

At the bottom of the frame is a long, snake-like dark brown nebula, Barnard 175, with the blue reflection nebula van den Bergh (vdB) 152 at its tip. This object has been dubbed the Wolf’s Cave Nebula, though that likeness is harder to discern. It is unclear where some of these nicknames come from, as many are recent appellations invented by astrophotographers. Some of the names have stuck, though few are “official.”

Perseus the Hero and Taurus the Bull

This is a portrait of the dust-filled region of sky from Perseus down to Taurus that includes the pink California Nebula (NGC 1499) at top down to the Pleiades star cluster (M45) at bottom. This is a stack of 48 x 2-minute exposures with the rare Samyang RF85mm f/1.4 lens stopped down to f/2.8, on the Canon EOS Ra camera at ISO 800. The lens was equipped with a 77mm Nisi Clear Night broadband filter.

The region of sky between Perseus and Taurus is rich in bright nebulas set amid large tendrils of dust in Taurus. The Pleiades star cluster lights up a portion of the dust clouds. And the pink California Nebula lies at the end of a large lane of dust.

The California Nebula

The California Nebula (named for its resemblance to the shape of the state) lies in Perseus. It is a bright emission nebula glowing in the red and pink light of hydrogen atoms, perhaps excited by blue-white Xi Persei, aka Menkib, at bottom. But it sits amid wider clouds of dust, here recorded as white and yellow.

IC 348

This complex mix of reflection and dark nebulas surrounds Omicron Persei. In some sections the dust is so dense it blocks all light from more distant stars. Once thought to be holes in the heavens, the photos of pioneering astrophotographer Edward Emerson Barnard in the early 20th century proved that dark nebulas are nearby, and obscure what’s behind them.

IC 348’s distance of only 700 light years means there isn’t much between us and the surrounding dark clouds. Oddly, though a popular target, as best I can tell, no one has come up with a nickname for this field. What can you see in the dark shapes?

The Pleiades / Messier 45

This frames the famous Pleiades or Seven Sisters star cluster (aka Messier or M45) set amid a dusty starfield in Taurus. The field is about 4.7° by 3.2°. This is a stack of 30 x 6-minute exposures with the Astro-Tech AT90CFT refractor at f/4.8 (using its 0.8x Reducer) and the filter-modified Canon R camera at ISO 800.

There’s no more famous deep-sky object than the blue Pleiades, or Seven Sisters. They feature in the mythology of almost all cultures around the world. The young blue stars are surrounded by bright blue reflection nebulosity, most prominent below the lower star Merope, a bit of nebula catalogued separately as NGC 1435.

While the Pleiades light up the core of the dust clouds blue, the dust clouds extend much wider and permeate the entire constellation of Taurus. However, the outlying clouds are very faint as they have no nearby source of illumination. The arc of nebulosity at top is most obvious. It was found by Barnard and is catalogued as IC 353.

Taurus the Bull

This is a portrait of the dust-filled region of sky in Taurus that frames the Hyades star cluster (at bottom) with bright yellow Aldebaran, up to the blue Pleiades star cluster (M45) at top. This is a stack of 48 x 2-minute exposures with the Samyang RF85mm f/1.4 lens at f/2.8, on the Canon EOS Ra camera at ISO 800.

Overlapping the previous constellation field, this framing extends farther south, continuing past the Pleiades down into the main section of Taurus the Bull, with the luminous yellow star Aldebaran marking the Bull’s eye. It is surrounded by the stars of the V-shaped Hyades star cluster, legendary half-sisters to the Pleiades.

Notable in this framing are the large dark tendrils of the Taurus Molecular Clouds, dense streams of dust only about 430 light years away. They are on my shot list for close-ups on upcoming clear winter nights.

NGC 1555 and Area

This is a framing of dust clouds among the stars of the Hyades star cluster in Taurus. The field of view is 4.7° by 3.2°. This is a stack of 30 x 6-minute exposures with the Astro-Tech AT90CFT refractor at f/4.8 and the filter-modified Canon EOS R camera at ISO 800, though no filter was used in taking the images.

This complex field lies on the northern edge of the Hyades. At upper right is the odd nebula NGC 1555, discovered by John Russell Hind in 1852 and variable in brightness due to changes in its embedded source star T Tauri, a prototype of a class of young, newly formed stars. An adjacent object, NGC 1554, was catalogued by Otto Struve, but has faded from view; thus it is called Struve’s Lost Nebula.

At lower left is the emission nebula Sharpless 2-239 embedded in the dense and brownish dust cloud LDN (Lynds Dark Nebula) 1551. It is dark indeed, but not black. Like most dark nebulas it has some warm colour.

Orion the Hunter

The most photogenic constellation is surely Orion the Hunter. It is filled with a rich collection of nebulas, including the eponymous Orion Nebula, bright enough to be visible to the unaided eye in the Sword of Orion, and #42 in Charles Messier’s catalogue.

The largest feature (though one best seen only in photos) is the arc of Barnard’s Loop, a possible supernova remnant or stellar wind-blown bubble that encircles Orion. It is usually plotted on sky atlases as just an easternmost arc, though it extends down and below Orion, all the way over to blue Rigel at bottom right.

At top is the large circular emission nebula Sharpless 2-264, surrounding the head of Orion and the star Meissa and a loose open star cluster Collinder 69. The nebula has become known as the Angelfish Nebula. It sits above orange Betelgeuse (at left) and blue-white Bellatrix (at right), marking the shoulders of Orion.

As you can see, there’s a winter-full of targets to go after in Orion. However, in my tour, I focused on two areas of dust and reflection nebulas.

Messier 78 Area

This is the bright reflection nebula complex that includes Messier 78 (the largest blue-white nebula) and NGC 2071 above it. This is a stack of 30 x 4-minute exposures through the Astro-Tech AT90CFT refractor with its 0.8x Reducer for f/4.8, and with the filter-modified Canon R camera at ISO 1600. No filter was employed here.

This frames one of the other often-neglected nebulas in Orion, Messier 78, one of the objects catalogued by Charles Messier in the 1780s. His is the popular “hit list” of deep-sky targets for all amateur astronomers.

In this case, M78 is accompanied by another smaller reflection nebula, NGC 2071. They are set in a region of dark clouds of interstellar dust, and framed by the red-magenta arc of Barnard’s Loop, aka Sharpless 2-276. The small reflection nebula at upper left on the edge of another dark cloud is van den Bergh 62. The large faint star cluster left of centre on the edge of the Loop is NGC 2112.

The Witch Head Nebula

This is the reflection nebula called the Witch Head, but officially IC 2118 (also with the catalogue number NGC 1909), near the very bright star Rigel, at lower left in Orion. This is a stack of 29 x 6-minute exposures through the Astro-Tech AT90CFT refractor with its 0.8x Reducer for f/4.8, and with the filter-modified Canon R camera at ISO 800. No filter was employed here.

The hot, blue giant star at lower left is Rigel at the foot of Orion. It illuminates the dust cloud that forms the fanciful shape of the blue Witch Head Nebula, or IC 2118. The nebula is actually over the border in Eridanus the River. Some magenta emission nebulosity also populates the field in Orion.

Indeed, as the wide-field photo above attests, all of Orion is filled with some form of nebulosity, be it emission, reflection, or dark.

There’s much more to go after when exploring the nebulous and dusty realms of the Milky Way. The sky is filled with stardust. Indeed, we are made of it!

— Alan, November, 2023 / www.amazingsky.com

November 6, 2019November 25, 2019

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.

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 “astronomical” 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 “Garnet Star” 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:

• How the Ra compares to previous “a” models and third-party filter-modified cameras

• How the Ra works for normal daylight photography

• Noise levels compared to other cameras

• 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 -15° C.

UPDATE — 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.

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. But …

• The EOS Ra has a factory adjusted white balance for ease of “normal” use — 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 — you can’t.

• And the Ra retains the sensor dust cleaning function. Camera modifier companies remove it or charge more to reinstall it.

• And the 30x live view magnification is very nice.

• 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.

That’s my take on it. I’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 — 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.

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 — 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 — 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 — 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.

February 17, 2019

Touring the Wonders of the Winter Sky

I present a tour of the deep-sky wonders of the winter sky.

While some might think the Milky Way is only a summer sight, the winter Milky Way is well worth a look!

In January and February we are looking outward from our location in the Milky Way, toward the Orion Spur, the minor spiral arm we live in. In it, and in the major Perseus Arm that lies beyond, lie hotbeds of star formation.

Artist's impression of the Milky Way (updated - annotated) — Courtesy European Southern Observatory

These star forming areas create a panorama of star clusters and glowing nebulas along the winter Milky Way and surrounding the constellation of Orion. The montage above shows the best of the deep-sky sights at this time or year.

(And yes, for southern hemisphere viewers I know this is your summer sky! But for us northerners, Orion is forever associated with frosty winter nights.)

The closeups below are all with a 200mm telephoto lens providing a field of view similar to that of binoculars. However, most of these nebulas are photographic targets only.

The Belt and Sword of Orion

This is the heart of the star formation activity, in the centre of Orion.

The bright Orion Nebula (or Messier 42 and 43) at bottom in Orion’s Sword is obvious in binoculars and glorious in a small telescope.

The Horsehead Nebula above centre and just below Orion’s Belt is famous but is a tough target to see through even a large telescope.

Barnard’s Loop at left is a wave of nebulosity being blown out of the Orion area by strong stellar winds. Any sighting of this object by eye is considered a feat of observing skill!

The Rosette Nebula and Area

Rosette and Christmas Tree Cluster with 200mm — The area of the Rosette Nebula (bottom) and Christmas Tree Cluster (top) in Monoceros with the Fornax Lightrack tracker and 200mm lens and filter modified Canon 5D MkII. This is a stack of 10 x 3 minute exposures at ISO 800.

The small cluster of hot young stars inside the Rosette Nebula is blowing a hole in the nebula giving it its Rosette name. Above is a loose star cluster called the Christmas Tree, surrounded by more faint nebulosity that includes the tiny Cone Nebula.

Gemini Clusters and Nebulas

The Clusters and Nebulas of Gemini — This is a stack of 10 x 3-minute exposures with the filter-modified Canon 5D MkII at ISO 800 and 200mm Canon L-Series lens at f/2.8. Some light haze passing through in some exposures added the natural star glows. I left those in as part of the stack to add the glows. Taken with the Fornax Lightrack tracker as part of testing. Taken from home on a rare fine and mild winter night, January 4, 2019.

This field of clusters and nebulosity is above Orion in Gemini, with Messier 35 the main open star cluster here at top. Below M35 is the tiny star cluster NGC 2158. The nebulosity at left between Mu and Eta Geminorum is IC 443, a remnant of a supernova explosion, and is aka the Jellyfish Nebula. The nebula at bottom is IC 2174, just over the border in Orion and aka the Monkeyhead Nebula.

Auriga Clusters and Nebulas

The Clusters and Nebulas of Auriga — This is a stack of 5 x 3-minute exposures with the filter-modified Canon 5D MkII at ISO 800 and 200mm Canon L-Series lens at f/2.8. Taken with the Fornax Lightrack tracker as part of testing. Diffraction spikes added with Astronomy Tools actions. Taken from home on January 4, 2019.

Above Gemini and Orion lies Auriga, with its rich field of clusters and nebulosity, with — from left to right — Messier 37, Messier 36, and Messier 38, as the main open star clusters here. Below M38 is NGC 1907. The nebulosity at right is IC 410 and IC 405, the Flaming Star Nebula.

In between them is the colourful asterism known as the Little Fish. Messier 38 is also known as the Starfish Cluster while Messier 36 is called the Pinwheel Cluster. The bright red nebula at top is Sharpless 2-235. The little nebulas at centre are NGC 1931 and IC 417.

The California Nebula

Now we enter Perseus, more an autumn constellation but well up through most of the winter months. It contains the aptly named California Nebula, NGC 1499, at top left, with the bright star Zeta Persei. at bottom A small region of reflection nebulosity, IC 348, surrounds the star Atik, or Omicron Persei, at bottom right. The star just below NGC 1499 is Menkib, or Xi Persei, and is likely energizing the nebula.

The Pleiades, or Seven Sisters

Pleiades M45 with 200mm Lens — The Pleiades with the Fornax Lightrack tracker and 200mm lens + Canon 5D MkII in a stack of 10 x 3 minute exposures at ISO 800.

Obvious to the eye and central to the sky lore of many cultures is the Pleiades, aka the Seven Sisters, in Taurus the bull. It is also called Messier 45.

This is a newly formed cluster of hundreds of stars, passing through a dusty region of the Milky Way, which adds the fuzzy glows around the stars — an example of a reflection nebula, glowing blue as it reflects the blue light of the young stars.

The Hyades

Below the Pleiades in Taurus lies the larger Hyades star cluster. The V-shaped cluster stars are all moving together and lie about 150 light years away. Bright yellow Aldebaran, the eye of Taurus, is an intruder and lies at only half that distance, so is not a member of Hyades but is a more nearby star. The smaller, more distant star cluster NGC 1647 appears at left.

Seagull Nebula

Low in my northern winter sky is the brightest star in the sky of any season, Sirius. Just above and to the east of Sirius lies the Seagull Nebula (at top left), also called IC 2177, on the Canis Major-Monoceros border. Like many of these nebulas. the Seagull is too faint to easily see even with a telescope, but shows up well in photographs.

Lambda Orionis Nebula

This is the head of Orion, with the red supergiant star Betelgeuse at bottom left and the blue giant star Bellatrix right at bottom right. The brightest star at top is Meissa or Lambda Orionis, and is surrounded by a large and very faint area of hydrogen nebulosity. The open cluster around Meissa is catalogued as Collinder 69.

While the winter Milky Way might not look as bright and spectacular as the summer Milky Way of Sagittarius and Scorpius, it does contains a wealth of wonders that are treats for the eye and telescope … and for the camera.

PS.: The techniques for taking and processing images like these form the content of our new Deep Sky with Your DSLR video course now being promoted on KickStarter until the end of February, and available for purchase once it is published later this spring.

See my previous blog post for details. Thanks and clear skies!

September 7, 2017September 7, 2017

Testing the Canon 6D Mark II for Deep-Sky

Following up on my earlier tests, I compare the new Canon 6D MkII camera to earlier Canon full-frame models in long, tracked exposures of the Milky Way.

A month ago I published tests of the new Canon 6D MkII camera for nightscape images, ones taken using a fixed tripod in which exposures usually have to be limited to no longer than 30 to 60 seconds, to prevent star trailing.

Despite these short exposures, we still like to extract details from the dark shadows of the scene, making nightscape images a severe test of any camera.

I refer you to my August 9, 2017 blog Testing the Canon 6D MkII for Nightscapes for the results. The 6D MkII did not fare well.

Here I test the 6D MkII for what, in many respects, is a less demanding task: shooting long exposures of deep-sky objects, the Milky Way in Cygnus in this case.

Why is this an easier task? The camera is now on a tracking mount (I used the new Sky-Watcher Star Adventurer Mini) which is polar aligned to follow the rotation of the sky. As such, exposures can now be many minutes long if needed. We can give the camera sensor as much signal as the darkness of the night sky allows. More signal equals less noise in the final images.

In addition, there are no contrasty, dark shadows where noise lurks. Indeed, the subjects of deep-sky images are often so low in contrast, as here, they require aggressive contrast boosting later in processing to make a dramatic image.

While that post-processing can bring out artifacts and camera flaws, as a rule I never see the great increase in noise, banding, and magenta casts I sometimes encounter when processing short-exposure nightscape scenes.

6D MkII at Four ISOs — The Canon 6D MkII at four typical ISO speeds in tracked exposures.

6D at Four ISOs — The original Canon 6D at four typical ISO speeds in tracked exposures.

5D MkII at Four ISOs — A Canon 5D MkII that has been filter-modified at four typical ISO speeds in tracked exposures.

For this test, I shot the same region of sky with the same 35mm lens L-Series lens at f/2.2, using three cameras:

• Canon 6D MkII (2017)

• Canon 6D (2012)

• Canon 5D MkII (2008)

Note that the 5D MkII has been “filter-modified” to make its sensor more sensitive to the deep red wavelengths emitted by hydrogen gas, the main component of the nebulas along the Milky Way. You’ll see how it picks up the red North America Nebula much better than do the two off-the-shelf “stock” cameras. (Canon had their own factory-modified “a” models in years past: the 20Da and 60Da. Canon: How about a 6D MkIIa?)

I shot at four ISO speeds typical of deep-sky images: 800, 1600, 3200, and 6400.

Exposures were 4 minutes, 2 minutes, 1 minute, and 30 seconds, respectively, to produce equally exposed frames with a histogram shifted well to the right, as it should be for a good signal-to-noise ratio.

Noisy deep-sky images with DSLR cameras are usually the result of the photographer underexposing needlessly, often in the mistaken belief that doing so will reduce noise when, in fact, it does just the opposite.

The above set of three images compares each of the three cameras at those four ISO speeds. In all cases I have applied very little processing to the images: only a lens correction, some sharpening, a slight contrast and clarity increase, and a slight color correction to neutralize the background sky.

However, I did not apply any luminance noise reduction. So all the images are noisier than what they would be in a final processed image.

Even so, all look very good. And with similar performance.

All frames were shot with Long Exposure Noise Reduction (LENR) on, for an automatic dark frame subtraction by the camera. I saw no artifacts from applying LENR vs. shots taken without it.

The 6D and 6D MkII perhaps show a little less noise than the old 5D MkII, as they should being newer cameras.

The 6D MkII also shows a little less pixelation on small stars, as it should being a 26 megapixel camera vs. 20 to 21 megapixels for the older cameras. However, you have to examine the images at pixel-peeping levels to see these differences. Nevertheless, having higher resolution without the penalty of higher noise is very welcome.

3 Canons at ISO 1600 — The three cameras compared at ISO 1600. Note the histogram and region of the frame we are examining up close.

3 Canons at ISO 3200 — The three cameras compared at ISO 3200. Note the histogram and region of the frame we are examining up close.

3 Canons at ISO 6400 — The three cameras compared at ISO 6400. Note the histogram and region of the frame we are examining up close.

Above, I show images from the three cameras side by side at ISOs 1600, 3200, and 6400. It is tough to tell the difference in noise levels, the key characteristic for this type of astrophotography.

The new 6D MkII shows very similar levels of noise to the 6D, perhaps improving upon the older cameras a tad.

Because images are well-exposed (note the histogram at right), the 6D MkII is showing none of the flaws of its lower dynamic range reported elsewhere.

That’s the key. The 6D MkII needs a well-exposed image. Given that, it performs very well.

3 Canons Stacked & Processed — The three cameras in stacked and processed final images.

This version shows the same images but now with stacked frames and with a typical level of processing to make a more attractive and richer final image. Again, all look good, but with the modified camera showing richer nebulosity, as they do in deep-sky images.

The lead image at the very top is a final full-frame image with the Canon 6D MkII.

As such, based on my initial testing, I can recommend the Canon 6D MkII (and plan to use it myself) for deep-sky photography.

Indeed, I’ll likely have the camera filter-modified to replace my vintage yet faithful 5D MkII for most of my deep-sky shooting. The 6D MkII’s tilting LCD screen alone (a neck, back, and knee saver when attached to a telescope!) makes it a welcome upgrade from the earlier cameras.

The only drawback to the 6D MkII for deep-sky work is its limited dark frame buffer. As noted in my earlier review, it can shoot only three Raw files in rapid succession with Long Exposure Noise Reduction turned on. The 5D MkII can shoot five; the 6D can shoot four. (A 6D MkIIa should have this buffer increased to at least 4, if not 8 images.)

I make use of this undocumented feature all the time to ensure cleaner images in long deep-sky exposures, as it produces and subtracts dark frames with far greater accuracy than any taken later and applied in post-processing.

I hope you’ve found this report of interest.

With the 6D MkII so new, and between smoky skies and the interference of the Moon, I’ve had only one night under dark skies to perform these tests. But the results are promising.

For more tips on deep-sky imaging and processing see my pages on my website:

Ten Tips for Deep-Sky Images

Ten Steps to Deep-Sky Processing

Thanks and clear skies!

December 19, 2015

A Panorama of the Entire Northern Milky Way

Panorama of the Northern Milky Way

In a sweeping panorama, here is the entire northern hemisphere Milky Way from horizon to horizon.

This is the result of one of the major projects on my recent trek to Arizona and New Mexico – a mosaic of images shot along the Milky Way over several hours.

The goal is a complete 360° panorama of the entire Milky Way, and I’ve got most of the other segments in previous shoots from Alberta, Australia and Chile. But I did not have good shots of the northern autumn segments, until now.

The panorama sweeps from Cygnus (at top, setting in the western sky in the evening), across the sky overhead in Perseus, Auriga and Taurus (in the middle), and down into Orion, Canis Major, and Puppis (at bottom, low in the southern sky at midnight).

The view is looking outward to the near edge of our Milky Way, in the direction opposite the centre of our Galaxy. In this direction the Milky Way becomes dimmer and less defined. Notable are the many red H-alpha emission regions along the Milky Way, as well as the many lanes of dark interstellar dust nearby and obscuring the more distant stars.

However, a diffuse glow in Taurus partly obscures its Taurus Dark Clouds — that’s the Gegenschein, caused by sunlight reflecting off cometary dust particles directly opposite the Sun and marking the anti-solar point this night, by coincidence then close to galactic longitude of 180° opposite the galactic centre.

Panorama of the Northern Milky Way (with Labels)

Here I provide a guided map of the mosaic. Orion is at lower right, while the Pleiades and Andromeda Galaxy lie near the right edge. The Andromeda Galaxy is the only thing in this image that is not part of the Milky Way.

The bright star Canopus is just rising at bottom, in haze. Vega and Altair are just setting at the very top. So the panorama sweeps from Altair to Canopus.

The sky isn’t perfect! Haze and airglow in our atmosphere add discolouration, especially close to the horizon. In my final 360° pan, I’ll use only the central portions of this panorama.

Now let’s put the horizon-to-horizon panorama into cosmic perspective…

Illustration of the Northern Milky Way Panorama

In this diagram, based on art from NASA’s Spitzer Space Telescope Institute, I show my Northern Milky Way Panorama in perspective to the “big picture” of our entire Galaxy, using artwork based on our best map of how our Galaxy is thought to look.

We are looking in a “god’s eye” view across our Galaxy from a vantage point on the far side of the Galaxy.

Where we are is marked with the red dot, the location of our average Sun in a minor spiral arm called the Orion Spur.

The diagram places my panorama image in the approximate correct location to show where its features are in our Galaxy. As such it illustrates how my panorama taken from Earth shows our view of the outer portions of our Galaxy, from the bright Cygnus area at right, to Perseus in the middle, directly opposite the centre of the Galaxy, then over to Orion at left.

The panorama sweeps from a “galactic longitude” of roughly 90° at right in Cygnus, to 180° in Perseus, over to 240° in Orion and Canis Major at left.

In the northern autumn and early winter seasons we are looking outward toward the outer Perseus Arm. So the Milky Way we see in our sky is fainter than in mid-summer when we are looking the other way, toward the dense centre of the Galaxy and the rich inner Norma and Sagittarius arms.

Yet, this outer region contains a rich array of star-forming regions, which mostly show up as the red nebulas. But this region of the Milky Way is also laced with dark lanes of interstellar “stardust.”

NOTE:

For larger images, see my Flickr site at https://www.flickr.com/photos/amazingsky/

TECHNICAL:

The panorama is composed of 14 segments, most being stacks 5 x 2.5-minute exposures with the filter-modified Canon 5D MkII at ISO 1600 and 35mm lens at f/2.8.

The end segments near the horizons at top and bottom are stacks of 2 x 2.5-minute exposures.

Each segment also has an additional image shot through a Kenko Softon filter to add the star glows, to make the bright stars show up better.

The camera was oriented with the long dimension of the frame across the Milky Way, not along it, to maximize the amount of sky framed on either side of the Milky Way.

The camera was on the iOptron Sky-Tracker. I shot the segments for this pan from Quailway Cottage, Arizona on December 8/9, 2015, with the end segments taken Dec 10/11, 2015. I decided to add in the horizon segments for completeness, and so shot those two nights later when sky conditions were a little different.