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Old 25-10-2013, 02:32 PM
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2stroke (Jay)
The devil's advocate

2stroke is offline
Join Date: Jul 2011
Posts: 816
Originally Posted by naskies View Post
With darks and dark flat frames, each pixel consists of the following:

LightPixel = Bias + Dark + LightSignal
FlatPixel = Bias + DarkFlat + FlatSignal
DarkPixel = Bias + Dark
DarkFlatPixel = Bias + DarkFlat

Calibration involves the following:

Calibrated Light Pixel = (LightPixel - DarkPixel) / (FlatPixel - DarkFlatPixel)
= (Bias + Dark + LightSignal - Bias - Dark) / (Bias + DarkFlat + FlatSignal - Bias - DarkFlat)
= LightSignal / FlatSignal
Thanks for that that sums it up even better. This looks like a very nice method so what are darkflats? I get that your using them to do away with bais but how are they taken? Are these a reversed values of flats? or flats - bais

Dark Flat
This is taken using the same settings (Exposure and ISO) as your "Flats (as above)" but with the telescope capped off so not to allow any light to enter the camera sensor. Take at least 25 exposures. googled lol to much codiene hahah
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