2017 December 10: William Herschel

December 10, 2017 10:30

Sonata for Organ       William Herschel (1738-1825)

"People, Look East"


William Herschel's father was oboist in the Hanover Military Band, and in due time his sons William and Jakob joined as well. At that time the crowns of Great Britain and Hanover were united under King George II, and the Hanover regiment found itself stationed in England. As the threat of war with France loomed, the Hanoverian Guards were recalled from England. After they were defeated at the Battle of Hastenbeck, Herschel's father sent his two sons to seek refuge in England. Although his older brother Jakob had received his dismissal from the Hanoverian Guards, Wilhelm was accused of desertion (for which he was pardoned by George III in 1782). Wilhelm, nineteen years old at this time, was a quick student of the English language. In England he went by the English rendition of his name, Frederick William Herschel.

In addition to the oboe, Herschel played the violin and harpsichord and later the organ, and he was a capable composer. From first violin and soloist for the Newcastle orchestra, Herschel work his way up the musical ladder, ultimately becoming organist at the Octagon Chapel, a fashionable chapel in Bath, as well as the Bath's Director of Public Concerts. His sister Caroline came to England in 1772 and lived with him in Bath, and after Herschel was appointed director of the Bath orchestra, his sister often appeared as a soprano soloist.

Herschel's music led him to the acquaintance of an amateur violinist, the Rev. John Michell, a Cambridge mathematics professor emeritus and England's leading geologist. Michell was also developing groundbreaking views on astronomy and the construction of telescopes. Michell sparked Herschel's interest in mathematics and lenses. After Michell's death in 1793, Herschel bought a ten foot long, 30-inch reflecting telescope from Michell's estate which he had to reconstruct due to damage in transport.

And thus began Herschel's lifelong passion for astronomy, and for telescope making. From the back garden of his house in Bath, and using a 6-inch aperture, 7-foot focal length Newtonian telescope "with a most capital speculum" (primary mirror) of his own making, Herschel began a systematic search of the night sky. In 1781 he discovered the planet Uranus (he originally named it the 'Georgian star' (Georgium sidus) after King George III, a politic move, but folks outside of England didn't much like the name. So for a time the planet was known as 'Herschel' until the name 'Uranus' was universally adopted.) The same year, Herschel was awarded the Copley Medal and elected a Fellow of the Royal Society, and a year later he was appointed "The King’s Astronomer". He continued his work as a telescope maker and achieved an international reputation for their manufacture, Over his career he constructed more than four hundred telescopes, the largest of which was 40 feet long with a 50 inch primary mirror.

From 1782 to 1802, with a 20 foot telescope (and others) in his backyard, Herschel conducted systematic surveys of the "deep sky". This quest meant he had to run inside and let his eyes readjust to the artificial light before he could record anything, and then he would have to wait until his eyes were adjusted to the dark before he could observe again. Later his sister Caroline became his recorder by sitting at a desk near an open window and William would shout out his observations. Ultimately he discovered over 2400 objects in the night sky. Herschel's discoveries were supplemented by those of his sister Caroline (11 objects) and his son John (1754 objects) and published by him as General Catalogue of Nebulae and Clusters in 1864. This catalogue evolved to include observations by other 19th century astronomers, and was published in 1888 as the New General Catalogue (abbreviated NGC) of 7840 deep sky objects. The NGC numbering is still the most commonly used identifying label for these celestial landmarks.

Herschel's work also included a systematic study of sunspots, the discovery of infrared radiation in sunlight, various moons of our planetary neighbors, and too many others to list here. He passed away peacefully at the age of 84.

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