In 1846, using mathematical predictions by French mathematician Urbain Le Verrier, German astronomer Johann Gottfried Galle became the first person to observe which planet?
Johann Gottfried Galle Galle, and a ring of Neptune have been named in his honor. Google celebrated Johann Gottfried Galle's 200th Birthday with Google Doodle https://www.google.com/doodles/johann-gottfried-galles-200th-birthday! Johann Gottfried Galle Johann Gottfried Galle (9 June 1812 – 10 July 1910) was a German astronomer from Radis, Germany, at the Berlin Observatory who, on 23 September 1846, with the assistance of student Heinrich Louis d'Arrest, was the first person to view the planet Neptune and know what he was looking at. Urbain Le Verrier had predicted the existence and position of Neptune, and sent the coordinates to Galle, asking him to verify. Galle found Neptune
Urbain Le Verrier intensely engaged for months in complex calculations to explain small but systematic discrepancies between Uranus's observed orbit and the one predicted from the laws of gravity of Newton. At the same time, but unknown to Le Verrier, similar calculations were made by John Couch Adams in England. Le Verrier announced his final predicted position for Uranus's unseen perturbing planet publicly to the French Academy on 31 August 1846, two days before Adams's final solution was privately mailed to the Royal Greenwich Observatory. Le Verrier transmitted his own prediction by 18 September in a letter to Johann Galle of the Berlin