Sir Frederick William Herschel FRS (15 November 1738 – 25 August 1822) was a German-British astronomer, the greatest observational astronomer of the day. He is best known for discovering Uranus in 1781. He also discovered infrared radiation, binary stars, and published important catalogues of stars and nebulae. Herschel built many telescopes, including the largest in the world at that time.