The Discovery of Neptune
The discovery of Neptune is a more complicated story than that of the other discoveries on this site, mostly because different astronomers and nations wished to take credit for its discovery.
Neptune was certainly observed by astronomers before its official discovery but was never recognised as a planet. Galileo even observed it in 1613.
Scientists were unsure about some small changes in the orbit of Uranus. They theorised that another large body was changing its orbit and the hunt was on for another planet. A British astronomer, John Couch Adams and a French astronomer, Urban le Verrier produced calculations of its orbit independently of one another.
Le Verrier sent his calculations to the Berlin Observatory where Galle and D'Arrest observed it telescopically on the same day.
To this day it is a subject of controversy about who should rightfully claim credit for it's discovery.