page_title: William Herschel
section_title: Astronomy
hierarchical_section_title: William Herschel / Astronomy
caption_attribution_description: English: Model of Telescope with which William Herschel discovered Uranus. In the Herschel Museum of Astronomy in Bath. The secret of Herschel's success as an observer was the power and magnification of his telescopes. This seven foot long, six inch diameter, ƒ14 reflector was particularly favoured. Its main mirror at the bottom of the tube and the secondary mirror near the top in front of the ocular were made of speculum metal. It was with a seven foot telescope that Herschel made the discovery of the planet Uranus in 1781
context_page_description: Frederick William Herschel, KH, FRS was a German-born British astronomer and composer of music. Frequently he collaborated with his younger sister and fellow astronomer Caroline Lucretia Herschel. Born in the Electorate of Hanover, William Herschel followed his father into the Military Band of Hanover, before emigrating to Great Britain in 1757 at the age of nineteen.
  Herschel constructed his first large telescope in 1774, after which he spent nine years carrying out sky surveys to investigate double stars. Herschel published catalogues of nebulae in 1802 and in 1820. The resolving power of the Herschel telescopes revealed that many objects called nebulae in the Messier catalogue were actually clusters of stars. On 13 March 1781 while making observations he made note of a new object in the constellation of Gemini. This would, after several weeks of verification and consultation with other astronomers, be confirmed to be a new planet, eventually given the name of Uranus. This was the first planet to be discovered since antiquity, and Herschel became famous overnight. As a result of this discovery, George III appointed him Court Astronomer.
context_section_description: Herschel's reading in natural philosophy during the 1770s indicates his personal interests but also suggests an intention to be upwardly mobile socially and professionally. He was well-positioned to engage with eighteenth-century "philosophical Gentleman" or philomaths, of wide-ranging logical and practical tastes.
  Herschel's intellectual curiosity and interest in music eventually led him to astronomy. After reading Robert Smith's Harmonics, or the Philosophy of Musical Sounds (1749), he took up Smith's A Compleat System of Opticks (1738), which described techniques of telescope construction. He also read James Ferguson's Astronomy explained upon Sir Isaac Newton's principles and made easy to those who have not studied mathematics (1756) and William Emerson's The elements of trigonometry (1749), The elements of optics (1768) and The principles of mechanics (1754).
  Herschel took lessons from a local mirror-builder and having obtained both tools and a level of expertise, started building his own reflecting telescopes. He would spend up to 16 hours a day grinding and polishing the speculum metal primary mirrors. He relied on the assistance of other family members, particularly his sister Caroline and his brother Alexander, a skilled mechanical craftsperson.
  He "began to look at the planets and the stars" in May 1773 and on 1 March 1774 began an astronomical journal by noting his observations of Saturn's rings and the Great Orion Nebula (M42).
  The English Astronomer Royal Nevil Maskelyne visited the Herschels while they were at Walcot (which they left on 29 September 1777).
  By 1779, Herschel had also made the acquaintance of Sir William Watson, who invited him to join the Bath Philosophical Society. Herschel became an active member, and through Watson would greatly enlarge his circle of contacts.
caption: Replica in the William Herschel Museum, Bath, of a telescope similar to that with which Herschel discovered Uranus
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