Lacaille, Nicolas Louis de

Lacaille, Nicolas Louis de

(nēkôlä` lwē də läkä`yə), 1713–62, French astronomer. As a result of his success in making meridional measurements in France under the patronage of the duke of Bourbon he was elected to the French Academy. He also became professor of mathematics at the Collège Mazarin, where he established an observatory in 1746. He was at the head of an astronomical expedition (1750–54) to the Cape of Good Hope. There he made observations of 10,000 southern stars, recording their positions; made the first measurement of an arc of the meridian of South Africa; and determined the lunar and solar parallax. Among his works are Astronomiae fundamenta (1757), Tables solaires (1758), Coelum australe stelliferum (1763), and Journal historique du voyage fait au cap de Bonne-Esperance (1763).

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.


Astronomiae fundamenta novissimis solis et stellarum observationibus stabilita. Paris, 1757.
Coecum australe stalliferum. Paris, 1763.


Berry, A. Kratkaia istoriia astronomii, 2nd ed. Moscow-Leningrad, 1946. (Translated from English.)