Hello readers. First off, apologies for the long delays between posts. Work’s changed up a bit recently…still working for the same company, just on a different contract. The new contract has a schedule very incompatible with my natural sleep schedule, and the winddown on the old contract took some extra time. I thought I’d have posted three or four new things by now, but alas. Anyway, I’ve got a LOT of stuff to share, stretching right back into the heart of summer. I’m working on getting all of that organized and written up as blogs, but in the mean time, I thought I’d share my latest astrophotography masterpiece: Andromeda Galaxy.
I don’t image galaxies all that often. Surprising as it may sound, imaging galaxies is a very different beast than imaging nebula. And some kinds of galaxies, particularly those closer to us, are quite different than imaging more distant galaxies. I’ve tried my hand at imaging more distant galaxies, without all that much luck. At the time, I had very little skill, an issue which I have remedied throughout most of this year. I’ll demonstrate my progress soon here with another image. Andromeda is one of the brightest objects in the sky. It is quite large, spanning an area of sky over three degrees by one degree. To put this size in perspective, the moon covers about half a degree (thirty arcseconds), which means you could fill up the area of Andromeda Galaxy with TWELVE MOONS! That’s BIG! It’s huge, actually.
Most people living in urban and suburban areas will never see Andromeda with their naked eye. Pollution from city lights, cars, and all the rest of the extensive amounts of energy we expend at night light up the sky, reflecting off of dust, clouds, and other particulate, blotting out the real sky and reflecting back a dull grayish-orange. For those who live well out of town, in rural areas, you may be able to glimpse Andromeda Galaxy. It sits out in front of Cassiopeia a short ways, in the neighboring constellation Andromeda itself. It’s a “fuzzy”, a dim, irregularly shaped object that often needs a slightly averted eye to see. If you live under exceptionally dark skies…the kind of dark skies you get when you are 100 miles from the nearest populated area, with no artificial light around, spend an hour or so to let your eyes adjust to true darkness, and you should be able to pick out Andromeda, as well as a number of other “fuzzies” in the same general quadrant of sky such as Triangulum Galaxy, the Double Cluster, and a few other globular clusters, with relative ease.
If you examine the image above more closely, you will notice two additional objects besides just the large galaxy itself. The scientific designation of Andromeda is M31, which stands for Messier 31, as it is one of the original night sky objects cataloged by the French astronomer Charles Messier in the years up through 1771. In addition to M31, M32 and M110 also make an appearance. M32 is the small globular structure just above the galactic disc. M32 is thought to be a separate but otherwise closely related entity from Andromeda, a massive globular cluster of stars that is orbiting it’s parent galaxy. M32 is a source of great insight into our own galaxy. It is thought that M32 is similar to our galaxies own Omega Centauri cluster, which in more recent years was reclassified as an object external to the Milky Way, nearly 16,000 light years distant…that is orbiting our home galaxy in a galactic polar orbit.
The other major object in this image is M110. This object is thought to be a companion galaxy to Andromeda, orbiting a couple hundred thousand light years away from it’s parent. M110 also very likely has parallels with our own galaxies neighbors. In our case, we have the Large and Small Magellanic Clouds, which are themselves in proximity and possibly orbiting the Milky Way by a couple hundred thousand light years themselves. Our galaxy, if viewed by an observer in the Andromeda Galaxy, would look very much the same to them as Andromeda does to us…with Omega Centauri appearing as a large globe above the galactic disk, and the SMC & LMC appearing much like M110 does.
From a scientific standpoint, Andromeda itself is a part of our “local group” of galaxies. The local group is about 10 million light years in size, which is itself a part of a galactic cluster hundreds of millions of light years in size, which itself is further a part of a supercluster, which in turn is a part of significantly larger structures in the universe that span billions of light years. Andromeda it about 2.5 million light years distant from the Milky Way, and is larger in overall size. Andromeda has more stars than the Milky Way, yet estimates of it’s overall mass are lower. It is a less dense, year more broadly spread galaxy than the Milky Way. It is thought that both galaxies are the two primaries of our local group, with the Triangulum Galaxy coming in third. M110 along with the LMC and SMC and a handful of other small irregular and elliptic galaxies, make up the next largest constituents, followed by several dozen small dwarf galaxies and objects barely more than faint blobs of light a few million light years away make up the rest. There are over 40 objects in total that make up the local group. Andromeda itself is part of a region packed with over a dozen of these objects, most of which cannot be seen without extremely large telescopes.
Total Integration Time: 3hr 5m
Number of Subs: 74
Flat Frames: 30x
Bias Frames: 200x
Exposure per Sub: 150s ISO 400 f/4.5
Integrated with DeepSkyStacker
Initial processing with PixInsight
Final processing with Photoshop w/ Carboni’s Astronomy Actions
Imaged under Bortle Scale Orange Zone, suburban city light pollution (grayish-orange skies), from my back yard outside of the Denver Metro area.