in A Dictionary of Astronomy
P ublished online February 2018 .
Reference Entry. Subjects: Astronomy and Astrophysics; Astronomical Instrumentation, Methods, and Techniques; Galaxies. 130 words.
On 1846 September 23, observing at the Berlin Observatory with the German astronomer Heinrich Ludwig d’Arrest (1822–75), he was the first to locate the planet Neptune, having started his...