William Herschel

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Herschel was born as Friedrich Wilhelm Herschel in Hanover, Germany, one of ten children (of which four died very young). He changed his name after moving to England at age nineteen to pursue a career as a musician. At the time, the crowns of England and Hanover were united under George II, and he had learned English when he had been sent to England a year earlier as a musician in the Hanoverian Guards regiment.

He became a successful music teacher and bandleader, played the organ and the oboe, and composed numerous musical works, most of which are largely forgotten today. He became Director of Public Concerts in Bath. His sister Caroline also came to England and lived with him.

His interest in astronomy grew stronger after 1773, and he built some telescopes and made the acquaintance of Nevil Maskelyne. He observed the Moon, measuring the heights of lunar mountains, and also worked on a catalog of double stars.

The turning point in his life was March 13, 1781, while residing at 19 New King Street, Bath, when he discovered Uranus. This made him famous and enabled him to turn to astronomy full-time. Naming the new planet Georgium Sidus in honour of King George III also brought him favour (the name didn't stick). That same year, Herschel was awarded the Copley Medal and was elected a Fellow of the Royal Society. In 1782, he was appointed "The King’s Astronomer" and he and his sister subsequently moved to Datchet (then in Buckinghamshire but now in Berkshire) on August 1, 1782. He also continued his work as a telescope maker, selling a number of them to other astronomers.

In 1783 he gave Caroline a telescope and she began to make astronomical discoveries in her own right, particularly comets. Caroline also served as his full-time assistant, taking notes while he observed at the telescope.

In June 1785, due to damp conditions, he and Caroline moved to Clay Hall in Old Windsor, and on April 3, 1786, they moved to a new residence on Windsor Road in Slough. William Herschel lived the rest of his life in this residence, which came to be known as Observatory House. It is no longer standing, having been demolished in 1963 to make way for a high-rise office building.

On May 7, 1788, he married the widow Mary Pitt (née Baldwin) at St Laurence's Church, Upton, near Slough. His sister Caroline then moved to separate lodgings, but continued to work as his assistant.

On August 28, 1789, he erected his renowned 40ft (focal length), 48 in aperture, telescope, discovering a new moon of Saturn on the very first night's observation, and a second moon within the first month of observation. The 40ft telescope proved very cumbersome, however, and most of his observations were done with a smaller telescope of 20ft focal length.

William and Mary had one child, John, born at Observatory House on March 7, 1792. In 1816, William was knighted "Sir William Herschel" by the Prince Regent. He helped to found the Astronomical Society of London in 1820, which in 1831 received a royal charter and became the Royal Astronomical Society.

On August 25, 1822, Herschel died at Observatory House and is buried at nearby St Laurence's Church, Upton.

His son John Herschel also became a famous astronomer. One of William's brothers, Alexander, also moved permanently to England, near Caroline and William though not in the same household, but was not a scientist.

His house in Bath, where he made many telescopes and first observed Uranus, is now home to the William Herschel Museum.

Other astronomical work

In his later career, Herschel discovered two satellites of Saturn, Mimas and Enceladus; as well as two satellites of Uranus, Titania and Oberon. He did not give these satellites their names; rather, they were named by his son John in 1847 and 1852, respectively, well after his death.

He also worked on creating an extensive catalog of nebulas. He also continued to work on double stars, and was the first to discover that most double stars are not mere optical doubles as had been supposed previously, but are true binary stars.

He also discovered infrared radiation (c.1800).

From studying the proper motion of stars, he was the first to realize that the solar system is moving through space, and he determined the approximate direction of that movement. He also studied the structure of the Milky Way and concluded that it was in the shape of a disk.

He also coined the word "asteroid".

He was known for eccentric theory that the Sun was inhabited.

William Herschel and Infrared Radiation

Herschel discovered infrared radiation by passing sunlight through a prism and holding a thermometer just beyond the red end of the visible spectrum. The thermometer indicated a temperature increase and this led to Herschel's conclusion that there must be an invisible form of energy.