As well as dark/flat file calibration - it can get pretty complex: https://nightskypix.com/calibration-frames/ https://nightskypix.com/calibration-frames/ http

As well as dark/flat file calibration - it can get pretty complex: https://nightskypix.com/calibration-frames/ https://nightskypix.com/calibration-frames/ https://www.astropy.org/ccd-reduction-and-photometry-guide/v/dev/notebooks/05-03-Calibrating-the-flats.html https://www.astropy.org/ccd-reduction-and-photometry-guide/v...