I have recently tested my camera with narrow band filters. Both N.I.N.A and Sharpcap recommended me to take 80 second subs at unity gain.
- 240 second
- 120 second
- 90 second
subs at various emission nebulae. 80 second sounds small for an osc camera with a duo-narrow band filter, but it does work.
my 4x80s (320 second) subs stacked looked very much like a single 1x300s, with the benefit of better stars. Both versions shot at the same temp/gain/offset.
Last night I was waiting for Saturn to approach the Meridian and to pass time, I was live-stacking the Eagle Nebula with 4 second subs and 2x the unity gain.
All that on an alt-az mount and not even using a flattener or cooling. At 10 minute integration, with sigma clipping enabled the image looked suprisingly nice, beside the amp glow and some elongated stars near the edges, which is expected.
So, it can be done, I also confirmed by doing this, that my flattener is junk, because the stars look good (no waterdrop like shape) without a flattener.
Also, easy way to check if you blown the stars:
- Also I learned something. Check your subs you're taking in both stretched and un-stretched. In un-stretched view if you see a lot shining stars, those are all over saturated. Just turn the stretching on/off in NINA after taking a sub.
There always be a few, but if you get a lot, you're over saturating your image. The less stars shown on an unstretched image (some will be blown, no matter what) the better chance for a nice image.
Edited by unimatrix0, 23 July 2021 - 09:48 AM.