An isolated patch of cirrus moved in around sunset and took its time moving away/dissipating during the early portion of the night. This prevented some photometry during the first two hours of the night, but wasn't much of a hindrance in obtaining polarization measurements. The rest of the night was clear, but very windy, with some gusts in excess of 30 mph. Slightly stronger winds are expected over the next two days.
The seeing was generally good (<1.5 arcsec) at the beginning of
the night and during a period after midnight. At other times, it
hovered around 2 arcsec.