Discovery images of Pluto's moon, Charon, captured by astronomer Anthony Hewitt. The images were then sent to astronomer Jim Christy for further analysis, and it was Christy who made the discovery of Pluto's moon.
Plates taken in 1915 by Thomas Gill at Lowell Observatory. Unbeknownst to Gill, these plates contained images of Pluto. The team that discovered Pluto in 1930 later realized this after comparing their own plates to pre-existing ones .