Discovery and exploration of the Solar System Domenico Cassini later discovered four more moons of Saturn and the Cassini division in Saturn's rings. Edmond Halley realised in 1705 that repeated sightings of a comet were recording the same object, returning regularly once every 75–76 years. This was the first evidence that anything other than the planets orbited the Sun. Around this time (1704), the term "Solar System" first appeared in English. In 1781, William Herschel was looking for binary stars in the constellation of Taurus when he observed what he thought was a new comet. Its orbit revealed that it was a new planet, Uranus, the first
Palomar Distant Solar System Survey trans-Neptunian objects and centaurs. and were among the objects discovered by this survey. It redetected Sedna but no other objects in Sedna-like orbits were identified. Palomar Distant Solar System Survey The Palomar Distant Solar System Survey (PDSSS) was a wide-field survey aimed at finding distant trans-Neptunian objects that used the robotic 1.2 m Samuel Oschin Telescope at Palomar Observatory and the QUEST large-area CCD camera. The survey was specifically designed to identify putative members of a Sedna-like population with perihelia greater than 45 AU. The limiting magnitude of this study was 21.3 in the R-band, it was sensitive out to