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Tips and Criticism - M31

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First time out with my new astro-mod DSLR last night (thanks @scitmon) and - according to the weather forecast - likely to be my last for a while so I'd like to polish my rather lacking Photoshop skills.

I attach below 2 files - the original tif stacked in DSS and a jpg I worked on in PS.  I'm not using any plug ins for PS other than the arcsin curves.  I'm aware there are some paid PS plug ins available which could help but I'd rather stick to working without, at least for the time being, in order to understand PS better.

It's a new camera and I still need to get to grips better with settings and technique (there's a lot of red data I need to get used to in particular) although I'm quite pleased with the result.  It won't win any prizes but for me it's good and the best image I've taken of M31 to date.  However, I'm sure there is plenty more data in the image to extract which is beyond my meagre skills.  Any tips or advice would be more than welcome, especially when it comes to dealing with the red channel.

If anyone is prepared to have a crack themselves please let me know what you do and how you get on.

For context the images were taken using a William Optics Z61ii with field flattener but no additional filter under a Bortle 5 sky with a rather bright half moon adding to the fun.  The final tif is a total of 98x60 sec subs (tracked, unguided) stacked in DSS with flats, bias, darks and dark flats (something else I'm experimenting with - this combo seemed to give the best final stack in this instance).

Thanks !



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I've had a very quick process with Pixinsight, I just did a crop, background neutralisation, colour calibration, histrogram and curves transformation:


I think I see slight elongation of stars which indicates your polar aligment is possibly slighly out, which would effect fine details.  Having said that, you have a very respectable attempt there, especially with the moon up.  I've always found it tricky to get any colour from M31, I think the trick is to get more data, preferably without LP from the moon.

Hope you are satisfied with the camera so far, you'll find it come into it's own with HA rich nebulas, not really much in M31.


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53 minutes ago, scitmon said:

I think I see slight elongation of stars which indicates your polar aligment is possibly slighly out, which would effect fine details.

Yeh it was very much a last minute decision to do anything last night.  We had torrential rain and I was about to hit the hay when the clouds parted and suddenly we had a clear night.  So rushed out at midnight, did a quick and dirty polar alignment, no guiding and restricted myself to 60sec subs.  The wind was still blowing mind which didn't help either.

Thanks for taking a quick look at the image.  I'm still fairly new to Photoshop so definitely more to learn and experiment with.  And very happy with the camera.  I would have gone for a nebula last night however time was getting on and wanted something easy to find.

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That's a nice image. 

My equipment gives very small field of view images so M31 is out of bounds!

I too stack in DSS then export to PS. I have a set routine of stretching and curves and maybe some sharpening.

I purchased what used to be known as Noel's Actions, a set of bespoke astro actions and also AstroFlat Pro or something similar. It might just be my shallow, noisy data but I've seen little in the way of desirable results from either!

YouTube is full of tutorials of advanced PS image processing that are quite astounding but life is too short and my brain is forgetting at a faster rate than it learns these days..!


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