22⁰ Circular Halos

22⁰ halos are created by refraction of light through randomly oriented hexagonal prism shaped ice crystals. These ice halos occur very frequently, even more often than rainbows! Light is refracted as it enters through one face of the hexagonal ice crystal, and is refracted once more as it exits through another face.

Due to the geometry of the ice crystal, rays of light are deflected through angles between 22⁰ and 50⁰ but more rays are deflected at angles of around 22⁰. This concentrates the light at this angle, creating a circle that is brighter than the sky around it.

 If you look carefully, you can see that the inner edge of the ice halo is red tinged, due to the fact that different colours of light refract at slightly different angles. 

Photo Taken by Michael Lane in Katikati, August 2016.

You can also get 22⁰ halos at night caused by moonlight, as shown in the photo below.

Photo taken by photographer Jonathan Usher.