Crepuscular Ray Over Abilene, Texas

November 20, 2011

Crepuscular over AbileneIMG_0056-1 (2)

: Steve Templeton; Steve's Web site
Summary Author: Steve Templeton; Jim Foster

The photo above showing what looks like a scene from a science-fiction film was captured in Abilene, Texas on August 29, 2011. This shaft of blue light penetrating a tear in a stratus cloud deck is simply a crepuscular ray seen from a sideways perspective. Though "crepuscular" refers to twilight, when such rays are most noticeable, crepuscular rays can occur anytime a cloud or a cloud layer moves in front of the Sun, even in the middle of the day. Because this ray is shadowed by the cloud layer above, it has a bluish hue -- only blue skylight is reaching the shadows.

Photo details: Camera Maker: Canon; Camera Model: Canon EOS 5D Mark II; Focal Length: 50.0mm; Aperture: f/10.0; Exposure Time: 0.0040 s (1/250); ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; Exposure: program (Auto); White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB; Software: QuickTime 7.6.6.