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Old 09-11-2018, 07:36 PM
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Peter Ward
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Peter Ward is offline
 
Join Date: Dec 2007
Location: The Shire
Posts: 8,090
Ah! This old chestnut.

A bias is a zero second exposure duration dark.

So, if you take a dark frame longer than zero seconds, you already have the bias information.

Not all cameras have perfectly linear responses, including my not-so-cheap SBIG STX16803, hence a dark library that matches the exposure times of the light frames, is the best way to calibrate your data IMHO.

Last edited by Peter Ward; 09-11-2018 at 07:42 PM. Reason: clarification
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