Quote:
Originally Posted by Startrek
To add more confusion to the topic of Calibration, I received a recommendation / suggestion on the APT forum by a member to use the following method -
Calibrate your Flats with Dark Flats
Don’t calibrate your Darks or Dark Flats , you only integrate them into a Master Dark and Master Dark Flat
You then calibrate your Flats using the Master Dark Flat , instead of using the Master Dark , and then integrate your Flats into a Master Flat
To clarify my understanding of the Calibration terminology -
Calibrate means to stack your Light frames with specific calibration frames ( dark, flat , dark flat or bias or alternatively a Master ) ?
Master means create a stacked file of the same type of calibration frame to be used with your Light frames in final stacking process ?
Integrate means to stack 2 types of calibration frames to form a single stack Master calibration file ?
Appreciate advice and confirmation on the above ( by the way I use Deep Sky Stacker )
Whoosh ........,
Thanks
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I think different people and different software approaches it differently. But, the idea is that you may need to calibrate your calibration frames.
Eg, darks may be calibrated with bias. Flats may be calibrated with bias or dark flats. Dark flats may be calibrated with bias. Bias is not calibrated by anything. Lights are then calibrated by the masters of all of the above.
Although I don't use PixInsight much the workflow I follow with that is basically - create master bias, create master darks by calibrating from master bias, create master dark flat by calibrating with bias, create master flat by calibrating with master dark flat, then use bias, flat and dark masters (but not dark flat master) to calibrate lights. At least, if memory serves, this was my process.
In APP I just stick all calibration frames into it and it does the work, but if for example I try and make a master flat without adding bias or dark flats it will have a whinge that it needs to calibrate the flats (with bias or dark flat) to make an accurate master flat.
Aside from processing software, individual cameras will also vary in terms of requirements, eg I have heard bias frames do not work with certain cameras, and for example on the 533, I can generally not bother with darks as long as my data is well dithered, as the combo of dithering and pixel rejection algorithms in the integration means that all hot pixels are removed and thermal noise is very low anyway. I have never been able to perceive much, if any, difference with the 533 between a stack from well dithered data sans darks, and the same data with darks.