On this day, in 1966, Saturn's moon Epimetheus was discovered by the astronomer Richard Walker. In 1978, Stephen Larson and John Fountain realised that the previous observations were best explained if there were two objects sharing very similar orbits, which was later confirmed by the Voyager 1 spacecraft. Epimetheus has a sibling called Janus, and Larson and Fountain officially share with Walker the discovery of Epimetheus.