Happy Birthday, William
Frederick William Herschel, born Friedrich Wilhelm Herschel, was born today in 1738. Herschel is most famous for the discovery of Uranus in addition to two of its major moons, Titania and Oberon. He also discovered two moons of Saturn - Enceladus and Mimas, shown below (they're tiny! yet large enough to be rounded by self-gravity), Enceladus against the clouds and Mimas below the rings. Mimas, by the way, is the "Death Star moon", its huge Herschel crater prominent in the photo at the bottom.