Giovanni Bianchini (1410 – c. 1469) was a professor of mathematics

Mathematics

Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 and astronomy

Astronomy

Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 at the University of Ferrara

University of Ferrara

The University of Ferrara is the main university of the city of Ferrara in the Emilia-Romagna region of northern Italy. In the years prior to the First World War the University of Ferrara, with more than 500 students, was the best attended of the free universities in Italy...

 and court astrologer of Leonello d'Este

Leonello d'Este

thumb|220px|Leonello D'Este portrayed by Pisanello.Leonello d'Este was marquis of Ferrara and Duke of Modena and Reggio Emilia from 1441 to 1450.-Biography:...

. He was an associate of Georg Purbach

Georg Purbach

Georg von Peuerbach was an Austrian astronomer, mathematician and instrument maker.-Biography:...

 and Regiomontanus

Regiomontanus

Johannes Müller von Königsberg , today best known by his Latin toponym Regiomontanus, was a German mathematician, astronomer, astrologer, translator and instrument maker....

. In the letters exchanged with Regiomontanus 1463/4 are mentioned works of Bianchini: Primum mobile including astronomical tables, 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

Samarkand

Although a Persian-speaking region, it was not united politically with Iran most of the times between the disintegration of the Seleucid Empire and the Arab conquest . In the 6th century it was within the domain of the Turkic kingdom of the Göktürks.At the start of the 8th century Samarkand came...

. 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.

The crater Blanchinus

Blanchinus (crater)

Blanchinus is a lunar crater that is situated in the rugged south-central highlands of the Moon. Adjacent to the south of Blanchinus is the crater Werner, and La Caille is attached to the northwest rim...

 on the Moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 is named after him.

See also

Giovanni Bianchini should not be confused with two similarly-named Italians with their own lunar craters: Francesco Bianchini

Francesco Bianchini

Francesco Bianchini was an Italian philosopher and scientist. He worked for the curia of three popes, including being camiere d`honore of Clement XI, and secretary of the commission for the reform of the calendar, working on the method to calculate the astronomically correct date for Easter in a...

 (1662–1729) (and the Bianchini crater), and Giuseppe Biancani

Giuseppe Biancani

Giuseppe Biancani was an Italian Jesuit astronomer, mathematician, and selenographer, after whom the crater Blancanus on the Moon is named...

 (1566–1624) (and the crater Blancanus

Blancanus (crater)

Blancanus is a lunar impact crater located in the rugged southern region of the Moon, to the southwest of the walled plain Clavius. To the northwest lies the comparably sized crater Scheiner, and south-southwest of Blancanus is the worn Klaproth....

crater).