Marto wrote: Hi, just about those dark frames, should they be the same exposure as the actual exposures?
It is not necessary to take them in the optical system and keep orientation of everything?
Dark need to be at same exposure/ISO but with cap on (also its recommended to block the viewfinder) and same sensor temperature - the light train can be altered, you were probably thinking of Flats where light train must remain identical (focus, orientation, etc..) - Note that Flats would help also to reduce vignetting!
  