Georg Joachim Rheticus

Georg Joachim Rheticus, who lived from 1514 to 1574 and was born Georg Joachim Iserin, was an Austrian mathematician, astronomer, cartographer, instrument maker, medical practitioner and teacher. He is best known for his trigonometric tables and as the sole pupil of Nicolaus Copernicus, whose De revolutionibus orbium coelestium he helped bring into print. Born at Feldkirch, where his father was the town physician, he took the surname of his mother's family, de Porris, after his father's execution in 1528, and later adopted the toponym Rheticus from Rhaetia, the Roman province that included his home region. Achilles Gasser took over his father's practice and helped him continue his studies, and he went on to Wittenberg, where he received his master's degree in 1536 and was appointed professor of the lower mathematics, arithmetic and astronomy through the patronage of Philipp Melanchthon. In 1539 he travelled to Frombork and spent two years with Copernicus. The lunar crater Rhaeticus and the asteroid 15949 Rhaeticus are named for him.