A sun dog or mock sun, formally called a
parhelion in meteorology, is an atmospheric optical phenomenon that consists of
a bright spot to one or both sides of the Sun. Two sun dogs often flank the Sun
within a 22° halo.
As the crystals sink through the air they
become vertically aligned, refracting the sunlight horizontally so that sundogs
are observed. Sundogs, or parahelia, are bright spots in the sky caused by the
refraction of sunlight off tiny ice crystals in the atmosphere.-
