Johann Gottfried Galle

Johann Gottfried Galle (9 June 1812 – 10 July 1910) was a German astronomer 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. He used the calculations of Urbain Le Verrier to know where to look.

Born in Radis, Galle studied at the University of Berlin from 1830-33. 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 (today 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 2 December 1839 to 6 March 1840. He died in Potsdam at age 98.

Two craters, one on the Moon and the "happy face" one on Mars, the asteroid 2097 Galle, and a ring of Neptune have been named in his honor.

Johann Gottfried Galle

First Neptune observation

Galle's Ph.D. thesis, finished in the year of 1845, was a reduction and critical discussion of Ole Rømer's observation of meridian transits of stars and planets on the days from 20 October to 23 October 1706. Around 1845 he sent a copy of his thesis to Urbain Le Verrier, but only received an answer a year later on 18 September 1846. It reached Galle on 23 September 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 the planet 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.

External links
Obituaries

Franz, J. (1910). "Anzeige des Todes von Johann Gottfried Galle". Astronomische Nachrichten 185 (19): 309. Bibcode 1910AN....185..309F. doi:10.1002/asna.19101851906. (German)
Chant, C. A. (1910). "Johann Gottfried Galle". Journal of the Royal Astronomical Society of Canada 4: 379. Bibcode 1910JRASC...4..379C.
"Obituary Notices : Associates :- Galle, Johann Gottfried". Monthly Notices of the Royal Astronomical Society 71: 275. 1911. Bibcode 1911MNRAS..71R.275..
"Obituaries: G. V. Schiaparelli, J. G. Galle, J. B. N. Hennessey J. Coles, J. E. Gore". The Observatory 33: 311. 1910. Bibcode 1910Obs....33..311..

Astronomical Images

NASA photo of the Mars crater Galle (a.k.a. "Happy Face Crater")