Tuesday, August 26, 2008

Sun Dog over Salisbury

Late Tuesday afternoon a sun dog appeared in the western sky over Salisbury. This is an interesting phenomenon that occurs when the sun is near the horizon and sunlight is refracted through ice crystals in the upper atmosphere. The University of Illinois website "WW 2010" explains it this way....

"Sun dogs, also known as mock suns or "parhelia", are a pair of brightly colored spots, one on either side of the sun.

Sun dogs form as sunlight is refracted by hexagonal plate-like ice crystals with diameters larger than 30 micrometers and their flat faces horizontally oriented.
Sun dogs are visible when the sun is
near the horizon and on the same horizontal plane as the observer and the ice crystals. As sunlight passes through the ice crystals, it is bent by 22 degrees before reaching our eyes, much like what happens with 22 degree halos. This bending of light results in the formation of a sun dog."

Interesting to look at to say the least.

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