Quote:
Originally Posted by LewisM
Are there any GENUINE advantages to using a combined master than a simple single auto-dark subtract for all images?
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Yes... a single dark frame contains a bunch of noise as well as dark current (read noise and also noise associated with the dark current). When you calibrate with that individual dark frame you'll remove dark current from your sub but you'll also add all that noise. A master dark composed of many individual dark frames should have much lower noise and won't introduce much additional noise to your subs during the calibration process.
The key to understanding this is to realise that dark calibration doesn't remove noise. It removes unwanted signal (bias and dark current.)
Cheers,
Rick.