Happy 10-10-10! Campaign 21 finishes on a pretty good night. Some very light cirrus occassionally visited the mountain from the north throughout the night. This was of little consequence to the polarimetry, but care had to be taken with the differential photometry and flux measurements of a few targets may have to be discarded. Thicker bands of cirrus during the last 2 hours of the night prevented all attempts at photometry and slowed polarimetry. Seeing was moderate (1.5 arcsec) with some periods near 2 arcsec.