Re flat frame I very well know the situation without flats - sometimes I forget them, or for one reason or the other they are not useful :-)
I completely understand that dust is not easy to get ignored - maybe it can be detected by means of the fact that it does not move at all while - at least at the resolution I use - most 'real' details move or are at least 'warped'. And dust usually is significantly larger than one pixel, but not very large. Just some ideas which come to my mind but maybe you have better ideas. Or just implement flats ;-)
If you need solar data as a use case just let me know.
Edited by LauraMS, 21 May 2019 - 05:12 AM.