Exposure Vs ISO on M31

[+Stu]

Morning. After having time to experiment with my camera settings on Friday I settled on 10 minute exposures on ISO400 with my modded 700D. To have time to do darks, I only ended up with 3 usable lights. I was bowled over when DSS did it's thing and produced an image with more detail than I expected! Is it a case of longer exposures and more of them to start getting the details on the outer portion of the target? Or an increase in ISO level up to 800?

[Bottletopburly]

Best iso for your camera is 800-1600 

https://astrophotography.app/EOS.php

[Clive]

3 hours ago, Stu said:

... Is it a case of longer exposures and more of them to start getting the details on the outer portion of the target? Or an increase in ISO level up to 800?

On my 200D I shoot at ISO 1600. At that ISO to keep the sky background to a reasonable level I usually expose for 3 min on M31.

[+Stu]

Cool, I'll give higher ISO/shorter exposure a go next time 👍

[philjay]

It all depends on how your camera handles noise Stu. My old 1000d is a bit noisy at 1600 so I use 800.

With brighter objects like m32 at longer exposures there is a danger of blowing out the core so I keep it to max of 4 minutes at 800 and take more subs.

[philjay]

M31 that should have said, doh