Thick bands of cirrus clouds had to be worked through during the first 3-4 hours of the night. After that, the sky became more friendly and several lengthy clear periods allowed normal operations. Despite the clouds, around 15 blazars were observed polarimetrically and photometry for most of these objects could be obtained. The seeing was the best of the campaign so far, with values of 1-1.5 arcsec throughout the night. This is in amazing contrast to the seeing experienced at the start of the previous night.
The normal source of infrared weather images of Arizona (with the state
divided into counties) was not available