Winter list of Objects
Winter marks the start of the first of two Galaxy Hunting seasons. It also sees the hub of our own Milky Way galaxy reign supreme over our night sky. I will also be mentioning a few naked eye delights – not everything requires a telescope.
As most galaxies require considerable aperture to see with much detail, I’ll limit this list to the more interesting objects. Some of the objects being mentioned will be relatively easy to acquire, but there will be a few that will test your development as an observer and push the limits of telescopes and eyeballs
Naked Eye.
• Scorpius, the constellation. Alas, most constellations do not resemble the namesake that they carry. But there are a few that are remarkable in the collection of stars. The scorpion is one of these. Starting from its broad head, then down to its red heart marked by the bright ruby star Antares, and then tracing the long sweeping “S” shape of its body all the way down to the stinger in its tail.
• A pair of crowns, Corona Borealis and Corona Australis. These are two very ancient constellations, also seen as crowns in many other ancient civilizations. The stars that make up Corona Borealis are brighter than those of Coronal Australis, but the string of stars of the latter make up a much more impressive arc.
• The Stingray – an Australian Indigenous constellation, aka the Southern Cross. Prior to European settlement of Australia, the local Aboriginal population has its own astronomical lore, and with that constellations. To some Aboriginal nations, the Southern Cross is seen as a pair of fish.
• The Cloud of Sagittarius – this is the single densest concentration of stars in the whole sky, and it lies in the direction of the core of the Milky Way. But this cloud is not the hub of the MW. Instead it is a clump of stars within the arm of our home galaxy that cuts in between us and the MW’s hub. Beyond this clump, and 30,000 light years from us lies Sagittarius A, the name of the Black Hole at the centre of our home galaxy. It is so named as it is the major source of radio waves from this direction of the sky. It is this supermassive black hole that is the driving engine of our Milky Way, whose massive gravitational pull is responsible for holding the hub together and the gross mass and gravitational pull of the hub that holds the MW together. We, our Sun, spins once around the MW’s hub every 230 million years. Now, 230 million years ago is when the age of Dinosaurs started here on Earth. Since then, the galaxy has since completed one full revolution, and now back at “point zero”, we appear on Earth… both eerie and cool at the same time!
Telescopic objects.
The Council of Giants.
Sounds like something out of Lord of the Rings, eh! Galaxies, like stars, tend to stick together in clusters. Our Milky Way galaxy sits within a cluster called the Local Group which is made up of at least 60 galaxies. Our group is tightly held, and there is a vast next to empty volume all around our local group before the next galactic cluster. But within this vast void resides twelve massive galaxies, almost like Sentinels standing guard around our local group. This is the Council of Giants.
At this time of year, several of these Sentinels can be seen. A few are relatively easy, but one is extremely challenging despite its colossal size and peculiar name. Just remember, the majority of galaxies unfortunately are a real challenge for novice eyes, especially from the suburbs as they are very easily washed out by light pollution, and certainly very little detail is hence visible in them, if anything much at all. But there are a few that do offer a little resistance to light pollution, but they do require patience and for you to trust your eyes.
• The Hamburger Galaxy, NGC 5128 in Centaurus. The Hamburger is so named because it resembles the said food as seen from side on with two buns with a pattie inbetween. It is located very close to Omega Centauri. The Hamburger from a dark site can be seen is 30mm finderscope, but from under light polluted skies it can appear as a faint “dumbbell” pair of lobes. The Hamburger is also known as Centaurus A, and was the first object to be found an enormous radio wavelength source with radio astronomy techniques, and from here in Australia! From Sydney’s Dover Heights actually.
• M83, the Southern Pinwheel, in Hydra. This is one of the easiest galaxies to see its spiral structure. But its arm structure requires a dark site and transparent sky (meaning no fog or mist, smoke or dust). Its arms have been spotted in scopes as small as 6”, but this is quite exceptional. Thankfully it sits just off the band of the Milky Way so it is not significantly obstructed by foreground stars and dust, same with the Hamberger.
• ESO 97-G13, the Circinus Galaxy, or Circinus Dwarf. This one demands the use of big aperture. It is literally “suck your eyeballs out of your head” difficult!!! This sucker is a real, REAL giant, but because it happens to sit behind a dense part of the Milky Way and hence heavily obscured, it was not discovered until 1977, and then mistakenly described as a “dwarf” galaxy because at first only its core was spotted, and it was not until several years later that its true status as a supermassive spiral galaxy was revealed. The Circinus Galaxy is more than double the diameter of our Milky Way galaxy, and our Milky Way is a blooming big sucker. There is so little observational information about the Circinus Galaxy that it took me a few years to actually identify it with my 17.5” scope. The problem is the heavy obscuring that the Milky Way does, so that the only “easy” part to spot is its core which looks like a very small unresolved globular cluster, and nothing like the big diameter round patch that is described in catalogues! Eventually I did spot it. And it was only with the time I spent on the sketch that I actually began to notice its much larger, but angel’s-breath faint disk! Oh so difficult, but oh so satisfying to nail this beastie.
Other objects
• NGC 4038 & 4039, the Antennae Galaxies, a pair of interacting galaxies in Corvus. This is a challenging pair of galaxies to see, and aperture is the key to seeing detail here. Though difficult, the Antennae Galaxies are a stunning example of galaxies that are highly distorted due to the enormous gravitational tidal forces acting on both systems. There are strands of stars and material being ripped out of both systems, some connecting both, and others being flung at high speed out of both into the empty abyss of space, lost for ever more to the inky darkness.
• M68, Globular Cluster in Hydra. A lovely orb of thousands of stars, not too well know because it sits so close to some other stunning objects in the same patch of sky.
If you have binos, grab ‘em! This is prime bino territory too!
Scorpius – The constellation contains a wealth of treasures along with its neighbour Sagittarius. Not only individual objects, but this area of the sky is riddled with masses of dark nebulosity that in most cases is invisible to telescopes, but wholly the realm of binos and small aperture rich field telescopes.
• M4, a gorgeous, somewhat loose globular cluster with a distinct “belt” of bright stars that cuts through its middle.
• The Table of Scorpius, around Zeta (ζ) Scorpii, is a contrast boon, with some brilliant supergiant stars beside some four individual open clusters of very different sizes and illumination of components stars and of a couple of nebulous complexes, and stunning asterisms, all within a small 3° field of view.
• M6, the Butterfly Cluster, so named because of its curious two-lobe structure resembling a butterfly. It is a naked eye object even from the big smoke (can be difficult from Sydney and Melbourne naked eye).
• M7, Ptolemy’s Cluster. OMG! My single most favourite in the whole sky! This big sucker is just AMAZING! Sure it is big and bright, but within its boundaries there lie three other open clusters, a globular cluster, half a dozen planetary nebulae, and a stunning criss-cross network of dark nebulosity that is totally invisible to telescopes other than rich field scopes and binos! The GC NGC 6453 is very remote and heavily obscured by the foreground Milky Way. It is but a small faint fuzzy patch that resists resolution. The planetary nebulae within Scorpius are all very small and need a technique called “blinking” in order to have any chance of spotting. Blinking makes use of an OIII filter placed on a paddle that is flicked in and out between your eye and eyepiece. The PN is easy to spot as it “pops” out.
Follow this link to get an idea on how to do the blinking method.
Sagittarius – one of two centaurs in the sky – no prizes for guessing which is the other… Sagittarius is the richest constellation in the sky for stars and deep sky objects. It is also the direction in which the core of our Milky Way resides. AND it is a killing field, where one poor small dwarf galaxy is in the process of being devoured by our monster Milky Way.
• M8, M20 & M21 trio. I’ve grouped these three together as they all within the field of view of binos and rich field scopes, and the lacework of dark nebulosity that intertwines around the three really needs mentioning too. This trio in being so close together are visible naked eye from all but the worst of light polluted skies. In many instances if you can shield your eyes from bright lights you may be able to catch of glimpse of their soft glow as two adjacent small fuzzy patches of light. The Lagoon and Trifid (M8 and M20 respectively) are two of the brightest nebulae in the sky. The Lagoon largely resembling a swirling oval cloud of smoke with a dark streak running through it, and the Trifid as a round patch with thin dark line cutting it into sections. M21 is a small bright open cluster beside M20, and it is what is mostly seen naked eye rather than M20 itself.
• M22, one of the largest globular clusters in the sky. M22 is one of some two dozen globular clusters within Sagittarius. It is a gorgeous silvery orb with a brilliant and large core, and dozens of strings of stars running in all directions as small ribbons within it.
• The Ink Spot (Barnard 86 or B86) is one of the blackest, most dense dark nebulae in the sky. What helps this is it lies deep within the mass of the Cloud of Sagittarius. Adding to the spectacle of its inkiness is it lies beside a small but brilliant open cluster, NGC 6520. Together the juxtaposition is a joy to behold. This particular challenge doesn’t stop here. Very close to this duo is a small/faint globular cluster, Djorg 2. This GC is very difficult to spot because is lies behind the densest star cloud in the sky. But thankfully it happens to sit within a small trough within the Cloud that is a little dimmer than the rest of the Cloud, and this line of sight coincidence allows the soft round glow of Djorg 2 to be seen. It lies just north west of the B86/NGC 6520 duo, about as far from the Ink Spot as the duo grouping is wide. Happy Hunting here!
• M17, the Omega or Swan Nebula. Another naked eye object that can be seen from urban skies. It happens to have a large round dark nebula sit over it that makes the bright arc of light around it resemble the neck of a swan.
Alex.