Quote:
Originally Posted by Camelopardalis
Have we figured out a way to get more than 12-bit data from the camera?
My angle is how we may need to adapt the way we image to the CMOS generation.
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get as much bit depth as you want by stacking:
1 sub = 12 bits
2 subs = 13 bits
4 subs = 14 bits
8 subs = 15 bits
16 subs = 16 bits
etc...
since you can do hundreds of short subs, the sky is the limit. 12 bits is not an issue at all
just stacked 19x 30 second subs and 10x 60 second subs of m83 to see how much of an SNR hit there was going to the shorter subs. I was using gain 100 and calculated that 1 minute should be about right. Images below show a linear mapping of the bottom 1000 ADU for the 30sec and 2000 ADU for the 60 seconds - no attempt was made to non-linear stretch, so everything bright is saturated.
Looks like the calculations were about right - the 60 second data looks good, but the 30 second data is down a bit on detail (seeing was worse as well, but contrast is down a bit). I had thought that 20 second subs would be OK and it still looks that way, provided that the gain is pushed up to maybe 200 to get the read noise right down.
By the way, there was no calibration or processing of these images - the camera is as smooth as.