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What is a Sundog?

A “sun dog” is a common name for an optical effect known as a “parhelion.” which is a type of halo, usually found in pairs, on the edges of a 22 degree halo on either side of the sun.
It is also sometimes called a “mock sun” because the bright spot in the sky resembles a small sun to the right and/or left of the actual sun.

Sun dogs are formed by plate-shaped hexagonal ice crystals in high and cold cirrus clouds or during very cold weather where ice crystals drift in the air at low levels, also known as diamond dust.

The sunlight refracts or bends as it shines through the ice crystals, which act as tiny prisms, sometimes separating the light into colors.
 John Shaw Sundogs: "Reflecting the Light to make the world a better place"
Photo Credit: Leah K.
Taken 10/15/2015