A Sundog is an "icebow". It forms when the sun shines through the ice crystals of cirrus clouds at a specific angle. The crystals break up the white light of the sun into the spectrum - ROY G. BIV (red, orange, yellow, green, blue, indigo and violet). Sometimes a pale halo of light can be seen around the sun or moon when the light shines through the thin layer of ice crystals. Kenny and I spotted this one afternoon in mid-January 2007 on the way to Atlanta to John Shaw's nature photography workshop.