Darkframe and Flatfield
In these sections you can select/create the master calibration images.
You can ignore this sections if you don't want to use the calibration images.
In order to create the master calibration images you must add a set of dark-frames and/or flatfield-frames to the respective lists.
If you already have a master-dark and/or a master-flatfield image, you can use them activating the 'use master-dark' and/or 'use master-flatfield' checkbox. Then you can select the master image by clicking the '...' button or writing the full path in the text box
Finally you can chose a correction factor by which the maste image will be multiplied in the stacking process.