How to generate a master flat from light frames?
sorry if this was already described somewhere, but I couldn't find it... is there a way in APP to generate a master flat using a large number of light frames?
Yes there is. You need to load all flat subs into APP in the 1) LOAD tab. Then if you have bias and dark frames and/or a master bias or dark, load those as well. In 2) CALIBRATE scroll all the way down and make sure that “create MasterBias, -Dark, -Flat” is ticked. Then click “create Masters and assign to Lights”.
thanks for your answer. But what I meant is to use light subs (with stars, and nebulae, and everything in) with the hope that taking a large number of them and with some clever averaging, it could be possible to build a flat field.
I usually take dark frames during each session, it's quite easy (simply putting the cap in front of my scope, and using the same settings for the capture as for the light frames); but capturing flat frames is more tricky, since it requires a color neutral uniformly illuminated field...
Maybe this is what you are looking for?