Ice Crystal Halos

MMT Observatory in Arizona has an automatic all sky camera that records the sky day and night. Archived videos are available from 2006 ( 1 ). Halos are visible in these recordings (although many displays are lost to the overexposure). Here are some examples:

• 22° halo / circumscribed halo. In the beginning possibly 9° halo ( 2 )
• Parhelion and patches of parhelic circle starting at 15:46 ( 3 )
• Parhelic circle starting at 13:58. Also 120° parhelion appears. The image above shows 60 seconds stacks of the display ( 4 )
• Parhelic circle appears at 21:15 ( 5 )
• 22° halo and some upper tangent arc, best starting at 02:00 ( 6 )

Ágnes Kiricsi, Marko Mikkilä and Mónika Landy-Gyebnár went through several months of the recordings listing the ones with halos ( 7 - 8 - 9 ). In ( 7 ) the best displays are pasted orange. Much of the MMTO Sky Camera material is still unchecked with regard to halos, certainly there are some decent displays to be found.