Friedrich Risner

Friedrich Risner (about 1533 to 15 September 1580), in Latin Fridericus Risnerus, was a German mathematician from Hersfeld in Hesse. From about 1565 he was an assistant to Petrus Ramus and in 1576 he became the first chair of mathematics at the Collège Royal in Paris. He is known above all for his 1572 edition Opticae thesaurus, which printed for the first time the seven books of Alhazen (Ibn al-Haytham) on optics together with Alhazen's work on twilight and the rising of clouds and the tenth book of Witelo (Vitello), two early pioneers of optics. The volume gave later mathematicians and scientists such as Kepler, Snellius, Descartes and Huygens a convenient route to medieval optical theory. Risner was also the first to propose a portable camera obscura for artists, a lightweight wooden hut with lensed holes in each wall and a paper cube inside for drawing. After the St. Bartholomew's Day massacre he fled back to Hersfeld, where he died and was buried in the abbey.