A Solar Halo Phenomenon

Abstract

A PHENOMENON which I have not seen described before occurred in a part of the horizontal ring of a solar halo on August 9, 1944. It consisted of dark bands moving like waves through the very bright ring. The sky was very clear at Cambridge on the morning of that day when a cloud trail was formed by an aeroplane. The trail moved from north-west in an easterly direction. At 11.20 a.m. a section of the horizontal mock sun ring appeared in that part of the cloud which in the north-east had the same altitude as the sun. As the cloud moved on, being steadily deformed and taking the shape of the letter S, the halo shifted slowly from left to right.