Quote:
Originally Posted by mldee
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  |
G'day Mike, I use Neb v2 and can briefly describe how I do them. You don't need to do Bias frames if you're doing Darks and Flats.
I prepare Darks first. Choose Batch, Align and Combine. In that window I pick Save Stack output method, None (fixed) alignment method, Std Dev 1.25 stacking function. Save as master_dark_ISO800_4min.fit or something like that. The None alignment method is the most important part there.
Next, Flats. Exactly same as Darks, but save as master_flat.fit.
Lights I Pre-process first, applying the master darks and flats. Then normalise, sometimes I use grade, then demosaic. Finally align and combine and save the stack as NGC1234_ISO800_20x4m.fit or something like that.
Hope that makes sense.
I haven't used the Bad Pixel Mapping side of things, so can't help you there. Hope this answers most of your questions.