High humidity prevents observations during the entire night. The weather front that ended observations early last night passed though just before noon. This dropped some rain on Kitt Peak and all of southern Arizona. It also dramatically dropped temperatures. The sky cleared shortly after sunset, but this dropped temperatures even further, which elevated the humidity to a point where observing was impossible. Light fog formed on Kitt Peak after 0300.
This night ends the first official Fermi/Steward Observatory observing campaign for Cycle 4. During the 12 nights of the campaign at the Bok Telescope, just about every weather pattern that one can get in Arizona (except snow, and we didn't miss that by much) was experienced. Fortunately, plenty of data were obtained as well.
The next campaign is scheduled at the Kuiper
Telescope in late October. In fact, Mt. Bigelow will be the base
of operations for the program until at
least after the holidays.