On 23 September 1846, Galle and astronomy student Heinrich Louis d’Arrest, since 1845 assistant at the observatory, discovered the planet Neptune, on the basis of positional calculations send by the Frenchman Urbain Le Verrier. After an initial lack of success they conferred the Le Verrier data with a newly published sheet of the „Berliner Akademische Sternkarte", edited by the Prussian Academy of Science. The letter from Le Verrier had coincidentally reached his close acquaintance Galle on the same day as Encke's 55th birthday, who gave his permission to search around the given celestial positions. At other observatories, the request of the French astronomer was viewed as not having sufficiently promising chances of success, of detecting another large planet on the basis of the deviations between theory and observations for the orbit of Uranus. This included Paris Observatory, whose director Le Verrier later became. By virtue of the discovery of Neptune, Berlin Observatory gained worldwide renown.