M31 , the "Andromeda" galaxy


I thought it appropriate, and I hope not stepping on any toes, to toss out what is only a fair-to-middling processing of the Andromeda Galaxy, obtainable to backyard astronomers with modest wildlife photography rigs.

Specific Feedback Requested:

All comments welcome!

Pertinent technical details or techniques:

This was from about 5 years ago and the processing software has stripped camera data. Without going back to another LR catalog to see the source files, I’m going to make a good guess that it was the Canon 7D2 and Canon 400 DO II, tracked on an Orion Sirius. Probably 4-5 hours of 1 minute subs, about 200 “dark” frames, about 50 “flat” frames and about 200 “bias” frames. Processed in PixInsight when I was about 1/3 of the way up the learning curve. The curve is a parabola so 1/3 wasn’t very far…

Getting good astro images is about getting good “subs” and using processing that will do a lot of heavy lifting.

The image is flipped from @Dan_Kearl’s recent post because my tracker followed the target across the meridian which flipped the image 180 degrees, and the initial camera rotation on the lens axis was a little different.

Is this a composite? No.

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What a beautiful image, Diane!
By “backyard astronomer” can I assume you took this in your backyard, not at a dark sky location? Is that why there are so many images taken, to allow the software to build a file that negates the effect of backyard sky pollution? Or maybe your backyard is in a dark sky area?
Anyway, this is just so impressive and beautiful.

Wow, this is amazing! I know absolutely nothing about astro and am too intimidated to try at this point, but goddamn it’s a beautiful genre. If this is 1/3 up the learning curve I can’t even imagine what 2/3 etc looks like…

Thanks guys! @Mark_Muller, I did take this in my backyard (actually side yard), but we’re in a pretty rural location. Sky darkness and clarity varies, but looking north on a clear, dark night (no moon) can be pretty good. Looking south we have light pollution from Santa Rosa and the greater San Francisco North Bay area. The clearer the air the less light pollution, which is bounce light off particulates in the air. That clarity is increasingly rare and part of the reason I have given up astrophotography, in addition to it being a bottomless pit for equipment and software.

The number of “subs” is due to the need to reduce noise beyond anything we could contemplate for daytime work. An individual 1 min exposure for this would yield almost no tonal structure. Good software will reduce noise of several different types and let the resulting histogram be stretched beyond anything we could imagine to bring out tonal detail – all without blowing out stars. That is the mind-boggling part for me!

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Thanks @Matthew_Chatham! 2/3 is about 1000 steps up. I can’t imagine it either… There is wonderful stuff on the internet, and a lot of horrible stuff.

Here are a few very quick grabs:


There are many more…

Here’s a much better M31 by Chris White (above):

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Mastering this kind of thing does sound daunting and so even more kudos for taking it on and doing so well with it. For me, astro photography is a little like underwater photography - it has hurdles and technical needs beyond what I have, use or am familiar with and that adds a patina of mystery to the images. That it’s out of reach and therefore more valuable or special. So I’m glad you posted this even if I don’t understand half of what goes into making it.

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Put a fox or groundhog in the middle of that and I might try to shoot it. Otherwise, I’m lost!
Absolutely none of the technical jargon made any sense to me, but it’s an impressive image. Nice work.

Now this is very impressive, the level of detail is amazing. The image is just so crisp and clear, it’s very clean looking. Now I see what you mean about software in terms of the results it can deliver. I also prefer the orientation or tilt of Andromeda here, it has a very dynamic look as a result.

As I said in the other Andromeda post, I am completely un-educated about this genre of photography, but that doesn’t diminish my appreciation of this . I gather the “subs” enhances the level of detail and the contrast of tonalities. Regarding colors however, is it fair to say that is more a matter of creative choice, or does the skill in using the software enter into what you get in terms of color? For example, In Chris Whites image there is more variety of color in the small stars than in your post. Is that creative choice, or skill level of the processing software?

Thanks guys! @Ed_McGuirk, the quality of the images involves all the above. Chris probably had darker skies, and most likely collected more photons, and probably had better optics – I haven’t dug back to his original post for this image. Some people will image a target over several nights and they can all be combined. Telescopes do better than camera lenses and special CCD sensors do better than our all-purpose cameras. But it’s all about collecting lots of images (subs) in order to get the level of noise reduction that lets detail and color be brought out. In addition to the images of the target itself, so-called Dark Frames and Bias Frames allow reduction of other kinds of sensor noise that we never see in daytime work, and Flat Frames correct for the light falloff at the edges of our lenses, which is significant when we start pulling out tonal detail. Then it becomes about software. Chris uses PixInsight, as I was, but he was much more accomplished with it. It is quite unlike any of the things we use. The initial histogram, after all the noise correction, is very dark with only a ghost of the object hiding in the darkest tones, and the stars occupying the right edge of the histogram. The histogram is stretched and a range of corrections is then made. It takes dark skies with minimal thermal disturbance, a lot of initial raw files, good software and some skill and knowledge to bring out a good image.

He does nature photography as well – I should try to recruit him here!

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Thanks for the explanation, it sounds like a lot of work, but the end result is beautiful.

Wow, this is amazing, Diane! Truly awe-inspiring. Actually, I can’t imagine having the patience tp both capture this and then process it! That said, I’m so happy you had that patience and perseverance. Thank you for sharing!

Your astronomic image are amazing. I feel as though I’m again back in that planetarium at the observatory in Griffith Park looking up at the ceiling. That was such a great show they put on. I loved your b&w image but the color version is even better. Although, I prefer the orientation in the original.