Weather Report for September 30, 2011

All night long there were clouds to the north and clouds to the south. Later in the night, there was even some lightning to the west(!). Somehow, Kitt Peak stayed in a clear spot the whole night, except for widespread cirrus at the start and a few isolated patches of cirrus passing through that didn't significantly affect observing. It was a very dynamic night in terms of seeing, which was very poor (2-4 arcsec) right after evening twilight. The rest of the night was much better, with the seeing being around 1-1.5 arcsec most of the time. There were some odd periods, however, when the seeing degraded to over 2 arcsec. The instrument problem that cropped up last night appears to be resolved and it turned into a nice, productive night.