Jerry,  You are not being a pain. Thanks for the benefit of your studied on eye on the flats and darks.   I am a sure that I downloaded what was in the "darks" directory and not the bias directory.  I was perplexed as you are, principally because the files in the GRAS-14 calibration directories are prefixed "G12" - which would indicate that they are for the GRAS-12 scope.  The GRAS owner, Arnie Rosen does not respond on email.  He hangs out on Skype to provide live tech support.  I have not installed Skype, so I have not contacted him. Clear Skies - Kurt