Detection of rings around Uranus

Abstract

AN occultation of the ninth-magnitude star SAO 158687 by Uranus on 10 March 1977 was predicted by Gordon Taylor¹ in 1973. Although the original prediction indicated that the occultation would be widely visible from land masses surrounding the Indian Ocean, subsequent work by Franz and Wasserman (at Lowell Observatory) showed that ground-based observations would be possible only from southern Africa and possibly from southwestern Australia². In view of the wealth of new information about Uranus which could be derived from photometric observations of this event³, we decided to attempt observations using the 61-cm Planetary Patrol telescope at Perth Observatory near Bickley, Western Australia. In fact, an occultation of the star by Uranus itself did not occur at Perth. Partial occultations of SAO 158687 by a series of rings around the planet were observed and are described here.