Lunar Pyramidal Crystal Halos, Chioggia near Venice imaged by Matteo Fuolega March 6, '09 23:26 local time. ©Matteo Fuolega, shown with permission.
Chioggia is on the Venetian Lagoon and there the three-quarter Moon was 49° high in Gemini. Surrounding it were several odd-radius halos generated by pyramidal ice crystals.
The innermost is the 9° radius halo. Beyond that and crossing Procyon is an 18° halo. There are perhaps traces of a 20° halo. The outer circles of 22,23 and 24° radius are not easy to tell apart.
The 13 to 20 faces of pyramidal crystals allow many ray paths. The numbers between square brackets [ ] give the entrance and exit ray face numbers.
|
