Sundog

This Sundog, or parhelion, was seen from Mowsbury Hill LNR hanging over Claphampark Wood this evening as the sun was setting. They occur at the same elevation as the sun and 22 degrees from it, possibly one on each side of the sun, but tonight there was only one. They are caused by sunlight passing through horizontal hexagonal plate ice cystals, leaving by a face at 60 degrees to the one it entered.

Photo by Keith Balmer