Quote:
Originally Posted by Slawomir
I checked and maximum ADU numbers for this nebula in 2-minutes subs in my photo are under 5000 units (except for bright stars that are already at maximum ADU), so it looks like I could go for much longer subs - will try it one night and see if I can capture fainter nebulosities like in your image 
Thank you Greg for explaining that. |
Its a question of how many stars are you willing to have overexposed.
You could mask out the stars in a narrowband sub if you are doing a narrowband RGB image and use lighten mode to let the RGB stars come through.
Trial and error I think is the key. 2 minutes is certainly very short for narrowband. These are 20 minutes and John Gleason uses 40 minutes with an FSQ.
Greg.