born April 8, 1732, Germantown, Pa.
died June 26, 1796, Philadelphia, Pa., U.S.
U.S. astronomer and inventor.
He was a clockmaker by trade but also built mathematical instruments and, it is believed, the first telescope in the U.S. In 1769 he observed Venus moving across the face of the Sun and noted that Venus has an atmosphere. Rittenhouse served as treasurer of Pennsylvania (1777–89), first director of the U.S. Mint in Philadelphia (1792–95), and president of the American Philosophical Society (1791–96).