Yeah well the weather forecast said it was going to be clear tonight starting just after nightfall. I had a hard time believing this since the cloud ceiling was about 100' AGL all day. But, like clockwork, the clouds just magically shuffled off at about 5pm. However, they left behind a high thin layer that was semi-transparent but ubiquitous. Unfortunately, tonight's basically full moon made the entire layer of cirrus clouds glow brightly. We could see a few bright stars (enough to get an alignment) but there wasn't anything to look at other than the moon, so we were only out there for about an hour. No chance to calibrate the camera.