Sun Dog

A sun dog, also known as a parhelion in meteorology, is an optical event in the atmosphere that consists of a bright spot on one or both sides of the Sun. The sun dog is a type of halo generated by the refraction of sunlight by ice crystals in the atmosphere. Sun dogs are often seen as a pair of softly colored patches of light around 22 degrees to the left and right of the sun, at the same altitude above the horizon as the sun. They can be viewed anywhere in the world at any time of year, but they are not always visible or bright. Sun dogs are most visible and noticeable when the sun is near the horizon.

Because the same plate-shaped ice crystals that generate sun dogs also cause the colorful circumzenithal arc, these two types of halo tend to co-occur. The rays flowing through the plate crystals become increasingly skewed from the horizontal plane as the sun climbs higher, causing their angle of deviation to increase and the sun dogs to migrate further away from the 22° halo while remaining at the same elevation.