John Thanks, one issue I've read about is occasional frosting/dew of the interior glass of the camera during high humidity. I've heard people allude to sbig putting in a heater to combat this. Have you experienced this or heard anything about it. My other question is spacing; that looks like a field flattener (AT2ff ?) in your imaging train any issues w/spacing to sensor (55mm I think) ? Thanks for your time, Marc
PS Happy w/it overall?

Good info John thanks. Looks like I'm in for a fun ride. Marc

Not sure why you can't see pic(?) it's showing up in my sent mail. I'm going to post as if it was a regular pic on the site. I had stretched the dark to check and see how even it was (check for light leaks) and I got that white band on the left side. I don't stretch for actual calibration. I was curious if you had ever stretched a dark and what yours looked like? Not sure what "normal" is on a ccd camera. Thanks, Marc