Nicolas Louis de Lacaille
Lacaille, Nicolas Louis de
Born May 15, 1713, in Rumigny, Ardennes Department; died Mar. 21, 1762, in Paris. French astronomer. Member of the Paris Academy of Sciences (1741).
In 1739–40, Lacaille verified the measurement of the extensive French arc from Dunkirk to Perpignan. From 1750 to 1754 he directed the astronomical expedition of the Paris Academy of Sciences to the Cape of Good Hope. He determined the position of 10,035 stars of the southern sky and measured arcs of the meridian greater than 1° and the acceleration of gravity. In 1758 he published solar tables that for the first time contained corrections for perturbations caused by the planets. Lacaille provided a method for determining cometary orbits and calculated the orbits of many comets. An exact value for the lunar parallax was obtained by comparing his observations of the moon in the southern hemisphere with similar observations made in Europe by J. Lalande.
WORKS
Astronomiae fundamenta novissimis solis et stellarum observationibus stabilita. Paris, 1757.Coecum australe stalliferum. Paris, 1763.