Astrojedi

Don, Thank you for this. It may also make sense to mention the SX Ultrastar cameras in the guide as well since they are also supported now. Not sure if you were already thinking about doing this in a subsequent version. Hiten

I agree that there is no difference in stacking vs. not stacking when we are talking about total photons collected as long as you are capturing sufficient dynamic range (less of an issue with low read noise cameras like the ASI224 or 187). But there are some other key differences. Stacking does reduce noise more quickly by averaging but the benefit disappears after a few subs. After stacking a few subs you are just focusing on collecting more photons (this is because the reduction in noise has a inverse square relationship to subs hence most of the gains are achieved with the first 5-7 subs). I have written my own scripts in Python for stacking, image analysis and lucky imaging which clearly show a reduction in noise/artifacts when I average the subs vs. an equivalent single exposure. The effect disappears with meaningfully longer exposures as the SNR of the the single exposure catches-up. Also the way the math works you need to use floating point and sufficient bit depth for stacking otherwise you lose dynamic range. But the real benefit of stacking is so obvious that it is easy to ignore. Stacking allows you to use lower quality mounts and achieve high quality results without doing a precise polar alignment or using guiding. Essentially it allows you to collect more photons than what your mount would permit were you not stacking. I have been imaging for 15 years and even now going beyond 3-5min subs takes a lot of effort wrt to polar alignment, mount quality, guiding, PEC etc. In comparison by stacking short exposures I was able to do 15 min integrations on a Nexstar SE Alt Az mount.

Don, Thank you and very thoughtful. Hiten