This has been the coldest night so far in this very cold campaign. The temperature dropped to 15 deg F by morning twilight. Skies were clear at the start of the night, but cirrus clouds moved in a little after 2200 local time and were a hindrance until about 0200. Work continued through the clouds and not a great deal of time was actually lost. Valid photometry was obtained for most targets. There were a a few periods of poor seeing (2-2.5 arcsec) at the beginning of the night, but otherwise the seeing stayed around 1.5 arcsec.
One more cold night is forecast and then temperatures are expected to