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
Space exploration winds of any planet in the Solar System, measured as high as 2,100 km/h. "Voyager 2" also examined Neptune's ring and moon system. It discovered 900 complete rings and additional partial ring "arcs" around Neptune. In addition to examining Neptune's three previously known moons, "Voyager 2" also discovered five previously unknown moons, one of which, Proteus, proved to be the last largest moon in the system. Data from "Voyager 2" supported the view that Neptune's largest moon, Triton, is a captured Kuiper belt object. The dwarf planet Pluto presents significant challenges for spacecraft because of its great distance from Earth