Sky lights up when cold weather comes
Photo: Arne Ader
Translation: Liis
Halo. Nõuni, Otepää hills.
It will be colder in the latter half of the week, and even the sun will show; with the heavenly lamp shining it can be worthwhile to look for halo phenomena. Halos appear when ice crystals reflect and refract the rays of the sun at a certain angle (most often an angle of 22 degrees): a ring of light appears in the sky.
In the atmosphere near the earth ice crystals usually float around only in winter weather. The crystals act as small glass prisms: one part of the rays is mirrored, one part is refracted in the prism. The halo rings can be complete or partial, depending where the ice crystals are located
Tags: 
