Johannes Werner

Johann(es) Werner (Latin: Ioannis Vernerus; February 14, 1468 – May 1522) was a German mathematician. He was born in Nuremberg, Germany, where he became a parish priest. His primary work was in astronomy, mathematics, and geography, although he was also considered a skilled instrument maker.

His mathematical works were in the areas of spherical trigonometry, as well as conic sections. He published an original work on conic sections in 1522 and is one of several mathematicians sometimes credited with the invention of prosthaphaeresis, which simplifies tedious computations by the use of trigonometric formulas, sometimes called Werner's formulas.

In 1500 he observed a comet, and kept observations of its movements from June 1 until the 24th.

This work further developed the suggestion of Regiomontanus that the occurrences of eclipses and cometary orbits could be used to find longitude, giving a practical approach for this method by means of the cross-staff. (The approach did not actually solve the problem as the instrument was not sufficiently accurate.)

His trepidations method to describe precession of the equinoxes De motu octauæ Sphær was posthumously challenged in 1524 by Nicolaus Copernicus in The Letter against Werner.

He is most noted for his work, In Hoc Opere Haec Continentur Nova Translatio Primi Libri Geographicae Cl Ptolomaei, written in 1514, a translation of the work Geographia (Ptolemy), written by Ptolemy.

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