Lacaille (la-kah-ye), who was born at Rumigny in France, started his career as a theology student, becoming a deacon before taking up astronomy. He became professor of mathematics at Mazarin College. In the late 1730s he worked with Jacques CASSINI on measuring the French meridian by means of triangulation. In 1751 he went to South Africa while Joseph de LALANDE went to Berlin to attempt to determine the lunar parallax, their separation by 85° giving them a sufficient base for an accurate result. While in South Africa he observed 10,000 stars, publishing a catalog of 2,000 of them in Coelum australe stelliferum (1763; Catalog of the Southern Sky).