Royal Observatory, Cape of Good Hope Spencer Jones, was active in an international project for determining the solar parallax through observations of the minor planet Eros. In the second half of the twentieth century Alan Cousins set up very precise southern standards for UBV and introduced a widely used system of VRI photometry that enjoyed international recognition for precision. In 1977 the occultation of the star SAO 158687 was observed by Joseph Churms from the former Royal Observatory and these observations provided needed confirmation of the Uranian rings discovered from the Kuiper aeroplane by Elliot et al. During the 19th century the Observatory was regarded as
Ring system it now appears that Saturn's rings might be quite old, dating to the early days of the Solar System. Fainter planetary rings can form as a result of meteoroid impacts with moons orbiting around the planet or, in case of Saturn's E-ring, the ejecta of cryovolcanic material. The composition of ring particles varies; they may be silicate or icy dust. Larger rocks and boulders may also be present, and in 2007 tidal effects from eight 'moonlets' only a few hundred meters across were detected within Saturn's rings. The maximum size of a ring particle is determined by the specific strength