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
Richard B. Dunn Solar Telescope adaptive optics in 2004 and remains a highly versatile astrophysical observatory which serves as an important test platform for developing new instrumentation and technologies. The Dunn Solar Telescope specializes in solar high-resolution imaging and spectroscopy. These observations allow solar astronomers worldwide to obtain a better understanding of the Sun. The telescope was inaugurated as the world's premier high spatial resolution optical solar telescope in 1969. With a horizontal rotating 40-foot-wide observing platform, such that instruments do not have to be mounted on the telescope itself, the Dunn Solar Telescope continues to offer a versatile, user-friendly setup. It has two high-order