William Herschel

William Herschel (1738-1822) was a German-born astronomer and musician who became one of the most important observational astronomers in history after emigrating to Britain in 1757. A skilled telescope maker, Herschel built some of the largest and most powerful reflecting telescopes of his era and used them to conduct systematic surveys of the night sky. On March 13, 1781, he discovered the planet Uranus, the first planet found in recorded history using a telescope, an achievement that doubled the known size of the solar system and won him a royal pension and the position of King's Astronomer. Herschel went on to catalogue thousands of double stars, nebulae and star clusters, developed influential theories about the structure of the Milky Way, and in 1800 discovered infrared radiation while investigating sunlight with a prism and thermometer. He worked closely throughout his career with his sister, the astronomer Caroline Herschel, who assisted his observations and made her own independent discoveries.