Born in what is in present-day Austria to wealthy parents (my dad was the town physician), we were as a family stripped of our surname when my dad was executed for stealing from his patients.
After studying and receiving a M.A. from the University of Wittenberg, I was appointed a professor of lower mathematics (arithmetic and geometry) at the Wittenberg University.
I left this position to study with noted astronomers, but ended up studying as the only student ever of Copernicus.
One of the inventions I made was an instrument for determining the length of a day, and gave it as a gift to Albert, Duke of Prussia.
My mathematical passion was the study of triangles, now called trigonometry; for example, I published the trigonometric sections of Copernicus' De revolutiobis under the spearate title On the Sides and Angles of Triangles.
Later, I published the tract Canon of the Science of Triangles, which contained the first published six-function trigonometric tables.
I died before publishing my opus Science of Triangles, but one of my students completed it, overseeing the hand computation of approximately 100,000 ratios to at least ten decimal places....still useable today in astronomical computations.
Georg Joachim de Porris, aka Rheticus (1514 – 1574)