 Galle received Le Verrier's letter on 23 September and immediately set to work observing in the region suggested by Le Verrier.Galle's student, Heinrich Louis d'Arrest, suggested that a recently drawn chart of the sky, in the region of Le Verrier's predicted location, could be compared with the current sky to seek the displacement characteristic of a planet, as opposed to a stationary star.Neptune was discovered just after midnight, after less than an hour of searching and less than 1 degree from the position Le Verrier had predicted, a remarkable match.