Remarkable Halo of August 21

Abstract

THE accompanying diagram is a sketch of the Danzig phenomenon as observed at Blackpool on Saturday, August 21, between 11.45 a.m. and 0.30 p.m. There had been heavy rain and stormy winds on the previous night and in the early morning up to 10 a.m. At 11.45 a.m. thunder cloud and cumulus extended all around the horizon, but in the vicinity of the zenith, where the 22° halo and the western portion of the mock sun ring now appeared, there was no trace of cirrus or other cloud form, although a very pale milky tint might be discerned. At noon the sky was overcast, but by 0.25 p.m. it was again clear at the zenith, and the complete phenomenon stood out very prominently, the 22° halo very vivid and brilliant with what would appear to be its arc of upper contact, the mock sun ring being very clear and of a silvery hue, and the mock suns; the two furthest from the real sun being apparently at the intersection of the mock sun ring with the 90° halo. This halo, however, was nowhere else visible.