Askar – 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