Abstract

Halos of unusual radii were seen in parts of southern England and in Holland in April 1974. This presentation is concerned with the phenomena observed in England on the evening of (according to most accounts) Easter Sunday 14 April 1974, from 1730hrs-1855hrs GMT. The most interesting feature of the display in that period was the variation of brightness around the circumference of the halos, which appeared to be due to the presence of incipient arcs of contact. The present investigation is an attempt to represent these features interms of crystal sub-types and/or orientations.

© 1983 Optical Society of America