I've had trouble getting morning flats and as a result in conjunction with Andor have learned that this "hardware platform" will not provide less than 100 pixel subframes. Andor has informed me they are not planning to fix this problem that their are no plans to upgrade the Aspen camera series or their filter wheels. They told me this problem isn't important enough because it affects "so few people" Apparently this flaw applies to Ethernet based camera or USB. The Alta series is unaffected. If you are having problems let me know I'd like to lobby Andor to do something about this. Not sure what I'm going to do when I have to measure PE, but depending on the software chosen this may be a non issue.