Frederick William Herschel (1738-1822) was a German-Anglo astronomer. Herschel was the first astronomer to study binary stars and, while searching for comets in 1781, he discovered Uranus, the first new planet to be discovered since ancient times. He also discovered two satellites of Uranus (Titania and Oberon, 1787), and two of Saturn (Mimas and Enceladus, 1789-90). King George III appointed William his Astronomer Royal in 1787. Herschel's sister Caroline Lucretia Herschel (1750-1848) worked alongside him and made significant contributions to astronomy, including the discovery of several comets and in particular the periodic comet 35P/Herschel-Rigollet, which bears her name.