Giovanni Bianchini

This article is about the mathematician. For the composer and organist, see Giovanni Battista Bianchini.
Giovanni Bianchini, in Luminarium atque planetarum motuum tabulae octoginta quinque
"Blanchinus" redirects here. For the lunar crater, see Blanchinus (crater). For other people, see Bianchini.

Giovanni Bianchini (in Latin, Johannes Blanchinus) (1410 – c. 1469) was a professor of mathematics and astronomy at the University of Ferrara and court astrologer of Leonello d'Este. He was an associate of Georg Purbach and Regiomontanus. The letters exchanged with Regiomontanus in 1463–1464 mention works by Bianchini entitled: Primum mobile (astronomical tables included), Flores almagesti, Compositio instrumenti.

Bianchini was the first mathematician in Europe to use decimal positional fractions for his trigonometric tables, at the same time as Al-Kashi in Samarkand. He was also probably the first to use the decimal point.[1] In De arithmetica, part of the Flores almagesti, he uses operations with negative numbers and expresses the Law of Signs.

He was probably the father of the instrument maker Antonio Bianchino.[citation needed]

The crater Blanchinus on the Moon is named after him.

  1. ^ Marchant, Jo (2024-02-19). "The decimal point is 150 years older than historians thought". Nature. doi:10.1038/d41586-024-00473-2.