M31 with multiple exposures

[Ishtar]

Hello all

Recently I have collected lots of data on M31 using my Atik 314L CCD. All these data were taken on separate days.

2 hours of Luminance @ 90 seconds

2 hours of Luminance @ 30 seconds

30 minutes of Luminance @ 15 seconds

Now my question:

Should I stack all these data together in Deep Sky Stacker and then post process in Photoshop as one image?

--- OR --

Should I stack the exposure groups separately, post process the individual images and then layer them into one using Photoshop?

Would anybody be able to point me to a good tutorial for imaging and processing M31?

Many thanks for your help.

[martin_h]

Take a look at this thread - http://stargazerslounge.com/imaging-tips-tricks-techniques/115901-imaging-over-several-nights.html

[Tim]

Or, you can stack each sequence in DSS, then use the Entropy stacking method to stack the three results into one image that should, in theory, contain the wider range of data.

DSS sorts your sets into their own little sub sets anyway, i'm just not sure what it does with them after that.

[Ishtar]

Thanks everyone