Image postprocessing and Smart Histogram

[AndreVilhena]

Hello everyone,

Does anyone have any comparative experience in post-processing images using the suggested settings of Smart Histogram (tipically lower exposure time and gain) and images using more "common" settings, with exposures up to 5 min and higher gains? For what I see, in the first case, images (after stacking) are much darker and I am wondering if one would be able to get vivid images. In trying to get that, I think I am over-stretching the images and introducing noise and artifacts.

Thanks,

André

[Menno555]

I am far from being an expert on this But I know it also depends on the camera.
I have a Zwo ASI 385MC (not cooled, smal FOV) and when I use the Smart Histogram (or Brain) settings, my captures are very/extremely dark. It's almost impossible to process the stacked captures. I do a mix then of the exposure time and gain: lets say the Brain suggests 36 seconds with gain 60, I do that on 60 seconds and gain 100. Then It's still somewhat dark but I don't have to over-stretch and the results are good. Needless to say that I don't use the Brain with the 385.
But when I use my Zwo ASI294MC Pro (cooled, bigger FOV), the Brain settings are giving good results and processing is no problem whatsoever.

Menno

[AndreVilhena]

Hello Menno555,

Thanks for the feedback. Actually I use also a Zwo ASI294MC Pro and so that's good news. In my first try I found very difficult the properly stretch but then, after writing my post, I found that the conversion from 32-bit to 16-bit done by DeepSkyStacker was the culprit and when doing it in Photoshop, the noise and banding introduced was much less. I still need to stretch a lot but final result is acceptable (for a Bortle 7 sky in full moon with no filter...). I'll give another go when sky conditions are better.

Cheers,

Andre