1713-1762

French astronomer whose redetermination of the Paris meridian revealed errors in Jacques Cassini's earlier measurements. This supported Isaac Newton's prediction that Earth is flattened at the poles. Lacaille observed nearly 10,000 stars during his Cape of Good Hope expedition (1750-1754) and included 1,942 of these observations in his Coelium australe stelliferum (1763). In conjunction with Joseph Lalande in Berlin, he measured the lunar parallax. Lacaille's 1761 Earth-Sun distance estimate was the first to treat Earth as other than a perfect sphere.