Johann Gottfried Galle
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Johann Gottfried Galle (June 9, 1812 in Radis, Saxony-Anhalt – July 10, 1910 in Potsdam, Brandenburg) was a German astronomer at the Berlin Observatory who, 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 (September 23, 1846). He used the calculations of Urbain Le Verrier to know where to look.
He had started to work as an assistant to Johann Franz Encke in 1835 immediately following the completion of the Berlin observatory. In 1851 he moved to Breslau (now Wrocław) to become professor of astronomy and the director of the local observatory.
Throughout his career he studied comets, and in 1894 (with the help of his son Andreas Galle) he published a list with 414 comets. He himself had previously discovered three comets in the short span from December 2, 1839 to March 6, 1840.
Craters on the Moon and Mars, and a ring of Neptune, were named in his honor.
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[edit] First Neptune observation
Galle's Ph.D. thesis finished in 1845 was a reduction and critical discussion of Ole Rømer's observation of meridian transits of stars and planets on the days from October 20 to October 23, 1706. Around 1845 he sent a copy of his thesis to Urbain Le Verrier, but only received an answer a year later on September 18, 1846. It reached Galle on September 23 and in it Le Verrier asked him to look at a certain region of sky to find a predicted new planet, which would explain the perturbations of Uranus. The same night, after Encke gave him the permission against his own judgement, an object fitting the description was found, and it was confirmed as being a planet over the next two evenings.
