Moon Corona

When the moon is shining through thin clouds, especially on a cold night, you may see it surrounded by a circle of faint color a few degrees in diameter. This is called a corona, and is formed by diffraction of light by water droplets or ice crystals. The same effect is sometimes seen around the sun, but may not be as readily noticed because it is so close to the overpowering light of the sun.

Date: January 27, 2007
Time: 6:43 p.m. MST
Location: Phoenix, Arizona
Camera: Olympus OM-1 35mm SLR on fixed tripod
Film: Fuji Provia 100F slide
Focal length: 50 mm
Aperture: f/4
Exposure time: 2 seconds
Scanner: Nikon Coolscan LS-2000 (cropped slightly)