Astronomer. Born Joseph Lefrançais de Lalande in Bourg-en-Bresse, France, he was a professor at the Paris Observatory who made important measurements of the Solar System. He devoted himself to the improvement of the planetary theory publishing in 1759, a corrected edition of "Edmond Halley's Tables" with a history of Halley's Comet whose return in that year he helped astronomer Alexis Clairaut to calculate it's position. In 1795, his staff made plots in the direction of Neptune's position in the sky and that Neptune might appear in the observation records. As a lecturer and writer he helped popularize astronomy in the 18th Century. He died in Paris, France.
Bio by: John "J-Cat" Griffith