CMOS Sensors - Comparison of Few Longer Subs and Mnay Shorter Subs

[gorann]

5 hours ago, symmetal said:

Do you have very dark skies gorann? I reach the sky background 10xRN^2 level at around 60s for lum with my Bortle 3 skies.

For gain 139, offset 50 as you use, the sky background10xRN^2 ADU level (16 bit) is 1290. If the median of your subs is much greater than this you can take more shorter subs and so reduce star bloating and get a bit more dynamic range. 

Alan

My SQM usually lies between 21.0 and 21.6, so quite dark with no major city within 100 km. The problem with shorter subs is of course data storage and stacking time. In a good night with 5 min subs I may still get nearly 100 subs to stack,

[wimvb]

1 hour ago, gorann said:

The problem with shorter subs is of course data storage and stacking time.

Yesterday I collected abt 880 frames. Thank heavens my camera is only 2.3 MP, file size 4.6 MB. But that's still 4 GB for one night. Unfortunately I had to throw the majority out due to clouds and the target disappearing behind the obsy wall. I must install my cloud detector.