sunhalo
A sun halo is an optical phenomenon that occurs when sunlight is refracted by ice crystals suspended in the atmosphere. These ice crystals, typically in the form of hexagonal prisms, act like tiny prisms, splitting the sunlight into its component colors, much like a raindrop creates a rainbow. The most common form of sun halo is a bright ring around the sun, often appearing at a distance of 22 degrees from the sun. This 22-degree halo is caused by light passing through the sides of hexagonal ice crystals.
Other less common sun halos can also be observed. These include sun dogs, which are bright spots