Background

Giovanni Antonio Magini was born on June 13, 1555, in Padua, Republic of Venice (now Veneto, Italy) to the family of a Padua citizen Pasquale Magini.

Education

Giovanni Antonio Magini graduated with a degree in philosophy from the University of Bologna in 1579.

Career

In 1588 Giovanni Antonio Magini was appointed to one of the two chairs of mathematics at the University of Bologna, having been preferred for that post to his younger contemporary Galileo. (The other chair was held by Pietro Cataldi, a mathematician of great prestige.) Magini alternated lectures on Euclid with classes in astronomy, which, stimulated by his passion for astrology, was actually his chief scholarly interest. Astrology itself had been taught at Bologna since 1125. Its study produced results occasionally useful to astronomers, as, for example, the more accurate calculation of celestial movements. Magini wrote several astrological works that were admired in their time, and also served the Gonzaga prince of Mantua as a judicial astrologer (with varying results). For this reason, he spent long periods of time in that city.

Magini’s mathematical work was essentially practical. In 1592 he published his Tabula tetragonica, a table of the squares of natural numbers which was designed to permit the determination of the products of two factors as the difference between two squares. In 1609 he brought out extremely accurate trigonometric tables, in which he introduced new terms for what is now called cosines, cotangents, and cosecants. Magini’s nomenclature enjoyed some currency and was later adopted by Cavalieri, who succeeded him at Bologna. Magini made further contributions to practical geometry, including works on the geometry of the sphere and the applications of trigonometry, for which he invented certain calculating devices that may be reconstructed from his texts. Of his lectures on Euclid, some notes relating to the third book are extant in the Ambrosian Library in Milan.

Although Magini’s fame in his own century rested upon these and other accomplishments (including his studies on mirrors and especially the concave spherical mirrors that he fabricated, one of which he presented to the emperor Rudolf II), he is today remembered chiefly as a geographer and cartographer. One of his earliest works was a commentary on Ptolemaic geography, in which he took up the problem of the topographical representation of the earth. He then embarked upon the ambitious project that, with interruptions, occupied him the rest of his life - an atlas of Italy, providing maps of each region (showing the borders of each state) with exact nomenclature and historical notes. The most complete edition of this atlas was published by his son, Fabio, in 1620, three years after Magini’s death. Unfortunately, even this edition represents only a small part of Magini’s actual work, since his notes for a greater volume, together with much of his library (particularly astrological works), were confiscated by the Roman Inquisition and apparently lost or destroyed.

Giovanni Antonio Magini corresponded with Tycho Brahe, Clavius, Abraham Ortelius, and Johann Kepler. His correspondence was edited in 1886 by Antonio Favaro.

Achievements

• Giovanni Antonio Magini was a recognized and respected scientist of his time, sometimes even more honored than his contemporaries memory of whom is stronger nowadays. The lunar crater Maginus is named after him. A United Kingdom Software company takes its name from the Maginus crater named in his honour.

Works

More photos

• book

  • Novae Coelestium Orbium Theoricae Congruentes Cum Observationibus N. Copernici 1608
  • Italia 1620
  • Ephemerides Coelestium Motuum 1620
  • Breue instruttione sopra l'apparenze et mirabili effetti dello specchio concauo sferico 1628
  • Continuatio ephemeridum coelestium motuum 1630
  • Patauini mathematicarum in almo bononiensi gymnasio professoris Tabulæ primi mobilis, quas directionum vulgo dicunt, quibus non solum directiones, tam secundum viam rationalem, quam
  • Primum mobile duodecim libris contentum, in quibus habentur trigonometria sphaericorum, et astronomica, gnomonica, geographicaque problemata, ac praeterea magnus trigonometricus canon emendatus, et au
  • Histoire Universelle Des Indes Orientales, Vol. 2: Divisée En Deux Livres

• map

  • Patrimonio di S. Pietro, Sabina et Ducato di Castro 1620
  • Marca D'Ancona olim Picenum 1620
  • Stato della Republica di Lucca 1620
  • Territorio di Orvieto 1620
  • Territorio di Brescia, et di Crema 1620
  • Territorio Trevigiano 1620

  • Moscoviae Imperivm

    1608

  • Ducato Di Urbino

    1620

  • Romagna olim Flaminia

    1598

Views

Like his astrological works, Magini’s writings on astronomy remain of only historical interest, due in large part to his adherence to Ptolemaic principles. He rejected the Copernican theory, which was then being vindicated by Galileo; the conservatism of his thought indeed made him Galileo’ enemy, and Magini more or less openly lent his support to libels against the younger man. Within the boundaries of his Ptolemaicism, Magini drew up complex theories, among them the multiplication of Ptolemaic spheres and orbits, and also performed some useful calculations. He was, in fact, much more skilled in calculation than in theory, and his ephemerides remained valid for a long time.

Magini devised his own planetary theory, in preference to other existing ones. The Maginian System consisted of eleven rotating spheres, which he described in his Novæ cœlestium orbium theoricæ congruentes cum observationibus N. Copernici (Venice, 1589).

A strong supporter of astrology, Magini defended its use in medicine in his De astrologica ratione (Venice, 1607). Magini collaborated closely with Valentine Naibod, and in this book he published De annui temporis mensura in Directionibus and De Directionibus from Naibod's unfinished manuscript Claudii Ptolemaei Quadripartitae Constructionis Apotelesmata Commentarius novus et Eiusdem Conversio nova. He was also interested in metoposcopy.

Connections

Giovanni Antonio Magini had a son named Fabio. Supposedly he was married.

Father:

Pasquale Magini

Son:

Fabio Magini

opponent:

Galileo Galilei

Acquaintance:

Tycho Brahe

Acquaintance:

Johannes Kepler

References

• Dictionary of Scientific Biography: Volumes 9 & 10
  1980