Frederick William Herschel was born in Hanover, Germany on 15th November 1738. At the age of 14 he joined the local regimental band as an oboist, and 4 years later he visited England with this band. He emigrated to England in 1757, and earned his living as a musician, including a stint of 16 years as organist at the Octagon chapel in Bath.
During this period he became fascinated by astronomy. In 1772 he bought his sister Caroline to England; she shared his interest in astronomy and they worked closely together thereafter.
The Herschels started work constructing telescopes and grinding mirrors in 1773. The first large telescope to be constructed was a 1.8-m Gregorian reflector built in 1774.
This and subsequent telescopes were used to survey the skies. Catalogues of double stars were published in 1782, 1785 and 1821, listing 848 stars in total. The resolving power of the Herschel telescopes revealed that the nebulae in the Messier catalogue were in fact clusters of stars. Catalogues of nebulae were published in 1802 (2500 objects) and 1820 (5000 objects). These subsequently formed the bulk of the New General Catalogue, published by Johan Dreyer in 1888, the nomenclature of which is still widely used.
The Herschels' most famous discovery was the discovery of the planet Uranus in 1781, the first new planet to be discovered since classical times. The sky survey revealed this as a disk, only 4 arcseconds in diameter. It was initially named 'Georgium Sidum' in honour of King George III. As a result of this discovery William Herschel was appointed court astronomer, and elected as a Fellow of the Royal Society. Grants were provided for the construction of new telescopes.
Herschel pioneered the use of astronomical spectrophotometry as a diagnostic tool, using prisms and temperature measuring equipment to measure the wavelength distribution of stellar spectra.
Other work included an improved determination of the rotation period of Mars, the discovery that the Martian polar caps vary seasonally, the discovery of Titania and Oberon (satellites of Uranus) and Enceladus and Minas (satellites of Saturn).
Herschel visited Paris in 1801 and met Laplace and Napoleon Bonaparte. He was knighted in 1816. He died on 26th August 1822, and his work was continued by his only son, John Frederick William Herschel.
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