3 arcsec at 290mm focal length › Forums › Photometry › Hyperstar for photometry? › 3 arcsec at 290mm focal length 29 August 2018 at 11:26 pm #579924 Robin LeadbeaterParticipant 3 arcsec at 290mm focal length is just 4.2um so with most cameras you are likely to be undersampled unless you defocus aren’t you ? Robin
