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Old 15-05-2010, 11:42 AM
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mldee (Mike)
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Join Date: Aug 2008
Location: Near Warwick, Qld, Australia
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Question: Preparing flats etc in Nebulosity

I am unable to find a clear procedure on how to prepare darks, flats and bias frames in Nebulosity 2.2.8. I have read the 2.2 manual but still a little unclear.

When preparing them, the manual says to treat them like 'light frames'. This would mean pre-proc including any subtractions, then debayer, stack, then post proc.

What is needed to make master Dark, Flat and Bias frames? Bias subtraction on darks and flats, grading? normalising? Debayering? and then the stacked frame is the master? Or is it simply bias subtraction on flats then stack without debayer? For darks, what steps? etc, etc. Specifically how they're done for Neb. The manual seems to credit me with more intelligence than I actually possess.

I understand Darks should be temp and exposure-time related to lights, but with the QHY8 at my level of quality, it's more the flats and bias I am trying to fathom out, as they're not directly related to those lights parameters and the absence of inherent dark noise is pretty impressive compared to my old 1000d or DSI III.

Finally, what are folks' experiences on Bad Pixel Mapping compared to Dark subtraction? Needed? I would prefer to leave out the Darks altogether, and so far I haven't seen any hot pixels either, but then again, there's 6 million of the little buggers
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