46°-halo

46°-Ring 

EE 12

Crystal orientation:

at random

Path of light:

3-1

Occurrence:

rarely
4-10 days a year

Picture of 22° and 46°-halo.
Photo: © Karl Kaiser, Schlägl / Austria, 11/10/96

Description:

A 46°-halo, also called the large ring, is a circle of light which has a radius of 46° with the sun in its centre. It is broader than the small ring, but also less bright. 46°-halos add up to only 2% of the cases when halos were reported. At sun elevations between 15° and 27° it may be mixed up with the supralateral arc. In fact, many reports of a 46°-halo seem to having actually been observations of the supralateral arc.

Formation:

A 46°-halo is caused by randomly orientated ice crystals with a refraction angle of 90°. The light enters a prism face of the crystal and leaves a base face.