German astronomer who with the assistance of his student, Heinrich Louis d’Arrest, was the first person to view the planet Neptune. French astronomer and mathematician Urbain Le Verrier had predicted the existence of the planet and had written to Galle with his results. These helped the German astronomer discover Neptune and is regarded as a monumental step in 19th century science.
By the way, Galileo Galilei was the first astronomer to observe Neptune but incorrectly classified it as a fixed star.
