Jean Baptiste Joseph Delambre (1749-1822), French astronomer. In 1792, Delambre published a work detailing the orbits of the Sun, Saturn, Uranus and Jupiter and its satellites. This work played an important part in the discovery of Neptune, as Uranus's actual orbit was shown to differ from that predicted by Delambre. It was later realised that this was due to the gravitational influence of an undiscovered planet. In 1795, Delambre was admitted to the Institute de France and in 1807 he was appointed to the chair of astronomy of the College de France, Paris. Artwork from The Gallery of Portraits with Memoirs, London, 1835.