Michael Maestlin

Michael Maestlin, a German astronomer, was born Sep. 30, 1550. Maestlin taught astronomy at the University of Tübingen, in southwestern Germany. In the 50 years that had passed since Copernicus proposed that the earth is a planet and moves around the sun, very few...

John Flamsteed

John Flamsteed, an English astronomer, was born Aug. 19, 1646. Flamsteed became the first Astronomer Royal of England in 1675, and he worked at the newly-built Greenwich Observatory for 44 years, observing the planets and the moon, and compiling a detailed catalog and...

Friedrich Wilhelm Bessel

Friedrich Wilhelm Bessel, a German astronomer, was born July 22, 1784 (see third image above). Bessel was the first astronomer to measure the parallax of a star. Stellar parallax is a slight displacement of a star, caused by the motion of the earth around the sun; the...

Christiaan Huygens

Christiaan Huygens, a Dutch scientist and inventor, died July 8, 1695, at the age of 66.  Huygens had the misfortune to occupy the same century as Isaac Newton; otherwise, he would probably be acclaimed as the greatest mathematical physicist of his era. He discovered...

Peter Apian

Peter Apian, a German mathematician and printer, was born Apr. 16, 1495.   After publishing in 1524 a book on cosmography (a Renaissance genre that combined geography and astronomy), Apian moved to Ingolstadt and set up his own printing press, and in 1532 he began to...