Flats with ASI071

Discussion of using SharpCap for Deep Sky Imaging
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ChrisFC
Posts: 6
Joined: Sat Feb 18, 2017 12:19 am

Flats with ASI071

#1

Post by ChrisFC »

I'm taking flats in SC by shooting clear sky before sunset. All good. Have gain=0 and set exposure time so that rgb histograms between 30-60%. I average 16 (usually) then save as a monochrome flat. I'm using raw16 bin x1 or x2 but the file is saved as a tiff.

The trouble is when I open the flat file in fitswork or fits liberator (16 bit) the histogram is saturated, at near max levels.

So I'm worried that I'm losing the dynamic range of the flat when stacking, which I assume will lead to undercompensation of vignetting. Is there something wrong with the flats or is it the way fitswork/liberator read the file?
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