Georg Joachim Rheticus

Georg Joachim von Lauchen, also known as Rheticus (February 16 1514 – December 4 1574), was a mathematician, cartographer, navigational and other instrument maker, medical practitioner, and teacher. He is perhaps best known for his trigonometric tables, and for facilitating the publication of Nicolaus Copernicus' De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres).

New surname

Rheticus was born at Feldkirch, Austria. Rheticus' parents both possessed considerable wealth and his father, Georg Iserin, was the town doctor of Feldkirch. Iserin, however, abused the trust of many of his patients, stealing items and money from many of their homes. He was convicted and executed for his crimes in 1528, and his family was stripped of their surname as a result. The son took as his last name a form of the Latin name for his home region, Rhaetia, a Roman province that had included parts of Austria, Switzerland and Germany; he would be called Rheticus.

Patrons

After Iserin's death, Achilles Gasser took over his medical practice. Gasser helped Rheticus continue his studies and was a strong support to him. Rheticus studied at Feldkirch, Zürich and the University of Wittenberg, where he received his M.A. in 1536.

Philipp Melanchthon, the theologian and educator, greatly assisted Rheticus in obtaining appointments at several universities. During the Reformation, Melanchthon reorganized the whole educational system of Germany, reforming and founding several new universities. In 1536 Rheticus was aided by Melanchthon in obtaining appointment to a teaching position in astronomy and mathematics at Wittenberg University.

Two years later, Melanchthon arranged for Rheticus to visit and study with noted astronomers of the day. Rheticus took this opportunity to visit Copernicus in Frombork (Frauenburg), Poland. On the way he first went to Nuremberg and visited the publisher Johannes Schöner and the printer Petreius. From there he proceeded on to Peter Apian in Ingolstadt and Joachim Camerarius in Tübingen, then to Achilles Gasser in his hometown.

Service to Copernicus

In May 1539 he arrived in Frombork (Warmia) and spent two years there with Copernicus. In September 1539 Rheticus went to Danzig (Gdańsk), just west of Frombork, and visited the mayor who gave Rheticus some financial assistance to publish the First Report or Narratio Prima. This Narratio Prima, published by Rhode in Danzig in 1540, is still considered to be the best introduction to Copernicus' De revolutionibus orbium coelestium. While in Danzig he interviewed the pilots to find out navigational problems. Rheticus had also visited the bishop of Chełmno Tiedemann Giese of Danzig.

In August 1541 Rheticus presented a copy of his work Tabula chorographica auff Preussen und etliche umbliegende lender (Map of Prussia and Neighboring Lands) to Duke Albrecht who had been trying to compute the exact time of sunrise. Rheticus made an instrument for him that determined the length of the day. Rheticus asked and received the permission of the duke for the publication of the Copernicus De revolutionibus. Albrecht requested of Rheticus that he return to his teaching position. He returned to the University of Wittenberg in October 1541, after earlier publishing the trigonometrical sections of the Copernicus De revolutionibus. In 1542 he traveled to Nürnberg to supervise the printing of the Copernicus material, published upon Copernicus' death in 1543.

Later years

The canon of Warmia Georg Donner and the bishop of Warmia Johannes Dantiscus were both patrons of Rheticus. Rheticus was also commissioned to make a staff for king Sigismund II of Poland, while he held a position as teacher in Kraków for many years. From there he went to Košice in the Kingdom of Hungary, where he died.

Science of triangles

For much of his life, Rheticus displayed a passion for the study of triangles, or trigonometry. In 1542 he had the trigonometric sections of Copernicus' Revolutions (chapters 13 and 14) published separately under the title, De lateribus et angulis triangulorum (On the Sides and Angles of Triangles). In Leipzig in 1551, Rheticus produced a tract titled, Canon of the Science of Triangles, the first publication of six-function trigonometric tables, though the term trigonometry was not used until 1595. This pamphlet was to be an introduction to Rheticus' greatest work, a full set of tables to be used in angular astronomical measurements. (Danielson, 140-141)

At his death, the Science of Triangles was still unfinished, but, paralleling his own relationship with Copernicus, Rheticus had acquired a student who devoted himself to completing his teacher's work. Valentin Otto oversaw the hand computation of approximately one hundred thousand ratios to at least ten decimal places. When completed in 1596, the volume, Opus palatinum de triangulus, filled nearly fifteen hundred pages. Its tables of values were accurate enough to be used as the basis for astronomical computation into the early twentieth century. (Danielson, 194-201)

References

• Richard S. Westfall, Indiana University. Rheticus, George Joachim. "Catalog of the Scientific Community of the 16th and 17th Centuries," The Galileo Project.
• J.J. O'Connor and E.F. Robertson, University St. Andrews, Scotland.
• Dennis Danielson (2006). The First Copernican: Georg Joachim Rheticus and the Rise of the Copernican Revolution. Walker & Company, New York. ISBN 0-8027-1530-3

External links

• O'Connor, John J.; Robertson, Edmund F., "Georg Joachim Rheticus", MacTutor History of Mathematics Archive, University of St Andrews
• Scienceworld article on Rheticus
• Narratio Prima