Flamsteed, John (16461719), an English astronomer. Flamsteed was appointed the first astronomer royal, in 1675, and Greenwich Observatory was built for him in 1676. His lifework was a greatly improved catalog of the positions and movements of about 3,000 starsHistoria Coelestis Britannica (3 volumes, 170725). Flamsteed received only a small salary and became a teacher and clergyman to supplement his income. Much of his work was done with equipment made at his own expense.