Sundogs Over Barrow, Alaska

June 18, 2019

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Photographer: Grant Gunn 
Summary Authors: Grant Gunn; Jim Foster

Featured above is a pair of dazzling sundogs (parhelia) observed from Barrow, Alaska on April 18, 2019. These mock suns, 22 degrees on either side of the Sun (when it’s near the horizon) and at the same solar altitude, form when sunlight is refracted through plate-shaped, hexagonal ice crystals. In this case, the crystals are free falling and not contained in clouds. For them to form, however, most of the crystals must be similarly oriented as they fall. Sundogs can be seen from any latitude and at any time of the year but are most conspicuous when the Sun is low in the sky.