Thread: QSI Arrives
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Old 28-08-2009, 03:35 PM
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Peter Ward
Galaxy hitchhiking guide

Peter Ward is offline
 
Join Date: Dec 2007
Location: The Shire
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Quote:
Originally Posted by rat156 View Post
Now, I do take bias frames and subtract them from my darks. I do this so that the darks are scaleable.

Cheers
Stuart
Yes, you can do this, but a hack like me doesn't because.

The dark noise pattern changes slowly over time
Dark noise is not completely linear
The undelying bias pattern can be (and is often) slightly random

In effect my dark library (ie Bias + dark) is constantly updated to provide the cleanest calibrated images possible.

It also doesn't work with back illuminated chips that have spectrally dependent fringing patterns (translation: flats change with colour! arrgh!)
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