|The Open Door Web Site|
HISTORY OF SCIENCE AND TECHNOLOGY
SIR WILLIAM HERSCHEL (1738 - 1822)
Sir William Herschel was born Friedrich Wilhelm Herschel in Hanover, Germany in 1738. His father, Isaac Herschel, was an oboe player in a military regiment band. Friedrich Wilhelm Herschel was one of ten children. He was sent to the garrison school where he learned to play the violin and the oboe. At the age of fourteen he joined the military and, like his father, played in his regiment’s band. Herschel visited England in 1755 when his regiment was posted there. This is not as strange as it might seem since the English king at that time was King George II, who was also the king of Hanover. Herschel’s return to Germany, along with his regiment, coincided with the start of the Seven Years War in 1756. How Herschel avoided military action in the war is unclear; some sources suggest that it was on health grounds and that Herschel’s “delicate health” allowed him to avoid the conflict. Whatever the true reason, Herschel left the military and, in 1757, at the age of nineteen, he arrived in England and changed his name to William Herschel.
Herschel learnt English quickly and joined the Durham militia where, not surprisingly, he played the oboe in the regimental band. By 1765 he was teaching music in Halifax and becoming well known as an organist. The following year he found employment as an organist and conductor in the Octagon Chapel in Bath. Bath was a very fashionable city and Herschel was able to join many groups and societies, becoming interested in philosophy and astronomy. He was also an avid student, studying harmonics which led to mathematics. He became fascinated with telescopes but was frustrated by their poor performance. He studied optics and started to build his own telescopes, using reflective lenses rather than refractive lenses that produced poor quality images.
Herschel built reflective telescopes that were fitted with large mirrors to greatly improve their ability to focus light. He became a very competent telescope maker. In 1772 his sister, Caroline, joined her brother and the two lived together for many years. Caroline helped Herschel make his telescopes and record observations of the night skies. Herschel constructed over 400 telescopes during his lifetime. His most famous telescope, first used in 1789, was over 12 metres long and contained a 1, 2 metre mirror. It remained the most powerful telescope in existence for the next fifty years.
Even with his first, less-powerful telescopes, Herschel could see a great deal more in the night sky than had ever been seen before. In 1774 he found the Orion Nebula and, in 1781, the planet Uranus. Later he was to discover Oberon and Titania, two of the moons of Uranus. These discoveries made Herschel famous. He was made a member of the Royal Society and awarded its highest honour, the Copley Medal for scientific achievement. The king, now George III, awarded Herschel £200 pounds per year and appointed him to the post of Court Astronomer.
Herschel and Caroline moved to “Observatory House” in Slough, near London in 1786. Here Herschel set up his “great” telescope and proceeded to systematically sweep the night sky. Over the next twenty years Herschel and Caroline observed 2500 new nebulae as well as adding substantially to our knowledge of the solar system. They discovered two more moons of Saturn and it was Herschel who introduced the word “asteroid” to the English language. His observations allowed Herschel to work out the shape of the Milky Way galaxy.
It is hard to believe that Herschel had the time to do anything else! However, his experiments on light heat, in 1800, led him to discover infra-red radiation and, in later life, he discovered that different types of quartz crystals would bend polarized light in different directions. In recognition of his outstanding achievements, Herschel was knighted by the Prince Regent in 1816. He founded the Astronomical Society in 1820 (since 1831 the Royal Astronomical Society) only two years before his death at the age of eighty four.