Frederick William Herschel KH FRS (1738 - 1822)
William was born in Germany, and trained as a musician as a child. Aged 19, he moved to England, where he taught music before becoming an organist. In 1772, his sister Caroline joined him in England to train as a singer. During this time, William's amateur interest in astronomy grew tremendously. He rented a small telescope, but dreamed of having his own observatory from which to work.
Instead, he learned how to build a large telescope, grinding and polishing the mirrors himself. His first telescope was completed by 1774, after which he spent nine years carrying out surveys of the sky. William published his own star catalogues in 1802 and 1820.
One night observing through his telescope, he realised that one object was not a star, but a planet - William had discovered Uranus. This was the first planet to be discovered since the ancient times, and the announcement of its discovery made William famous overnight. King George III immediately made William the Royal Astronomer. He was elected a Fellow of the Royal Society, and was granted money for the construction of new telescopes.
His other work included determining the rotation period of Mars, observing the Martian polar caps, and discovering the moons Titania and Oberon (of Uranus), and Enceladus and Mimas (of Saturn). William also discovered infrared radiation, by observing its effect on a thermometer. William pioneered the use of 'spectrophotometry' in astronomical observations. This involved the use of prisms and temperature probes to measure the wavelength distribution of the spectra of stars.
When the Royal Astronomical Society was founded in 1820, William was made its first President. He died in 1822, and his work was continued by his only son, John Herschel.