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Geminiano Montanari.

Geminiano Montanari (June 1, 1633 – October 13, 1687) was an Italian astronomer, lens-maker, and proponent of the experimental approach to science.

He is best known for his observation, made around 1667, that the second brightest star (called Algol as derived from its name in Arabic) in the constellation of Perseus varied in brightness. It is likely that others had observed this effect before, but Montanari was the first named astronomer to record it. The star's names in Arabic, Hebrew and other languages, all of which have a meaning of "ghoul" or "demon", imply that its unusual behaviour had long been recognised.

Montanari was born in Modena, studied law in Florence, and graduated from the University of Salzburg. In 1662 or 1663 he moved to Bologna, where he drew an accurate map of the Moon using an ocular micrometer of his own making. He also made observations on capillarity and other problems in statics, and suggested that the viscosity of a liquid depended on the shape of its molecules. In 1669 he succeeded Giovanni Cassini as astronomy teacher at the observatory of Panzano, near Modena, where one of his duties was to compile an astrological almanac. He did so in 1665, but perpetrated a deliberate hoax by writing the almanac entirely at random, to show that predictions made by chance were as likely to be fulfilled as those made by astrology. In the period shortly after Galileo Galilei, experimentalists like Montanari were engaged in a battle against the more mystical views of scientists such as Donato Rossetti.

On 21 March 1676 Montanari reported a sighting of a comet to Edmund Halley.

Montanari's observations of the great comet of 1680 are mentioned twice in the third volume of Newton's Principia.[1]

In 1679 Montanari moved to a teaching post in Padua, but almost all records of this period of his life have been lost. A letter survives from 1682 recording a sighting of Halley's Comet. He also wrote on economics, observing that demand for a particular commodity was fixed, and making comments on coinage and the value of money (1683).

A crater on the Moon, at 45.8S, 20.6W, is named after him.


Prostasi fisicomatematica, 1669
  • De motionibus naturalibus a gravitate pendentibus (1667)
  • Pensieri fisico-matematici (1667)
  • La Livella Diottrica (The Spirit Level) (1674)
  • Trattato mercantile delle monete (1680)
  • L'Astrologia Convinta di Falso col Mezzo di Nuove Esperienze e Ragioni Fisico-Astronomiche o sia la Caccia del Frugnuolo (1685), in which Montanari describes his and his colleagues' random predictions intended to disprove astrology


  1. ^ Isaac Newton, The Principia: Mathematical Principles of Natural Philosophy, edited by Bernard I. Cohen and Anne Whitman, Berkeley, University of California Press, 1999, pp. 913-915, 927.

Further reading[edit]

  • Gómez López, Susana, Le passioni degli atomi. Montanari e Rossetti: Una polemica tra galileiani, Florence, Leo S. Olschki, 1997.
  • Rotta, Sergio, 'Scienza e "pubblica felicità" in G. Montanari', in Miscellanea Seicento, Florence, Le Monnier, 1971, vol. 2, pp. 65-208.
  • Vanzo, Alberto, 'Experiment and Speculation in Seventeenth-Century Italy: The Case of Geminiano Montanari', Studies in History and Philosophy of Science, 56 (2016), pp. 52-61.

External links[edit]

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Geminiano_Montanari — Please support Wikipedia.
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137 news items

Osservatorio Astronomico Sormano

Osservatorio Astronomico Sormano
Thu, 28 Apr 2016 03:07:30 -0700

Quel che è certo è che la prima documentazione ufficiale circa la variabilità di Algol risale al 1670 ad opera dell'astronomo italiano Geminiano Montanari, mentre il preciso periodo di variazione venne calcolato un secolo dopo dall'inglese John Goodricke.

Ostia Tv (Comunicati Stampa) (Registrazione) (Blog)

Ostia Tv (Comunicati Stampa) (Registrazione) (Blog)
Sat, 16 Apr 2016 04:48:45 -0700

Ai visitatori Mondo Convenienza riserverà altre divertenti sorprese, con l'omaggio di gadget per lo sport e il tempo libero e piccoli accessori utili per lo shopping. Informazioni sul punto vendita ROMA FIUMICINO Via Geminiano Montanari (Centro Comm.le ...

Huffington Post

Huffington Post
Tue, 29 Dec 2015 08:37:34 -0800

It was previously thought that Italian astronomer Geminiano Montanari discovered Algol in the late 1660s, but the researchers concluded that the “demon star” was discovered much earlier — and that the ancient Egyptian papyrus is the oldest preserved ...

Community Idea Stations

Community Idea Stations
Wed, 06 Jan 2016 06:48:34 -0800

Until recently, Geminiano Montanari was credited with the discovery of Algol in 1667, but this find shows that perhaps this variable star was of more importance to humanity much earlier. Regardless, this find further shows us how the ancient world ...


Fri, 20 Nov 2015 13:22:30 -0800

This week, between 11 p.m. and midnight local time, the constellation immortalizing one of the greatest heroes of Greek mythology — Perseus — will pass directly overhead. Its prominent variable star, Algol — known as "the Demon" — will be vividly ...

Astronomy Now Online

Astronomy Now Online
Fri, 18 Dec 2015 14:52:56 -0800

Italian astronomer Geminiano Montanari noted Algol's variability in 1667, but it was not until 1783 that British amateur astronomer John Goodricke correctly suggested its cause. AN graphic by Ade Ashford / Stellarium. “We can explain why the period of ...

XãLuận.com tin tức việt nam 24h cập nhật

XãLuận.com tin tức việt nam 24h cập nhật
Mon, 04 Apr 2016 02:21:31 -0700

Bản đồ sao chính xác cổ nhất cho đến ngày nay xuất hiện từ thời Ai Cập cổ đại năm 1534 trước Công nguyên, điều này cho thấy Ai Cập có nền thiên văn học rất phát triển. Đến thế kỷ 17, một nhà thiên văn học sống ở thế kỷ 17 là Geminiano Montanari sống ...

New Historian

New Historian
Fri, 01 Jan 2016 17:46:02 -0800

It was formerly believed that Geminiano Montanari, an Italian astronomer, had discovered Algol sometime in the late 1660s. Now researchers have concluded the Demon Star had been found much earlier. The research was recently published in the journal ...

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