Discovery of Neptune

Unlike Uranus and Ceres, Neptune was not discovered by accident. It was proposed that a planet beyond Uranus could account for irregularities in Uranus' orbit. Independently, two astronomers, John Couch Adams in England and Urbain-Jean-Joseph Le Verrier in France, calculated the position of this yet unknown planet.

The search began. The British astronomer James Challis, using Adams' predictions, observed the planet on the night of August 4, 1846, but failed to compare his observations with those of the previous night and did not recognize the planet. On September 23, 1846, the planet was finally found on the first try by the German astronomer Johann Galle using Le Verrier's predictions.
Who Discovered Neptune?
Who should receive credit for discovering Neptune? Adams or Le Verrier who predicted its position? Challis who saw it but did not know it? Galle who found it? Controversy raged.

It was fortunate that Neptune was discovered in the mid-19th century. Just 30 years later the planet was far from the positions predicted by both Adams and Le Verrier.