ABSTRACT
Recognized by his contemporaries as an ingenious mathematical astronomer, he never published any of his work, and his reputation nearly vanished. In the 1980s, several copies of Nicolaus Copernicus’s (1473-1543) De revolutionibus (1543) have been identified as heavily annotated in Wittich’s hand, and these marginalia give a greater appreciation of his influence as an itinerant teacher of technical details of the New Astronomy. In particular, diagrams in a copy of Copernicus’s book show that Wittich had proposed a partial geoheliocentric system, an embryonic form of the Tychonic system. Marginalia in another copy of De revolutionibus show Wittich at work on the prosthaphaeresis method, whereby multiplication and division could be reduced to addition and subtraction through the use of trigonometric identities.
