Multiple Light Pillars
April 29, 2013
Photographer: Sebastian Riel; Sebastian's Web site
Summary Author: Sebastian Riel; Jim Foster
The multiple vertical shafts pictured above are light pillars. Whereas Sun pillars can be observed on occasion near sunrise and sunset, when sunlight glints off the undersides of ice crystals in cirrus clouds, these pillars have another light source; highway and shopping mall lights. In this case, the artificial lighting is being reflected off diamond dust falling just above the surface. Diamond dust is ice (ice crystals) that forms when the air is very cold and the lower atmosphere is quite stable. With this type of precipitation, accumulation is negligible since little moisture is squeezed out of the cold, dry atmosphere. The temperature when I took this shot was about - 4 F (- 20 C) Note that a light pillar's color depends on the color of the artificial lighting. Photo taken in the early morning hours of December 27, 2012.
Photo details: 30 second exposure; f/7.1; ISO 100; with an exposure adjustment of plus 2 (to keep the snow from looking grey).