Geminiano Montanari

Geminiano Montanari
Born(1633-06-01)1 June 1633
Died13 October 1687(1687-10-13) (aged 54)
NationalityItalian
Alma materUniversity of Salzburg
Known forDiscovery of the variations in brightness of Algol
Scientific career
FieldsAstronomy
Mathematics
Physics
Economics
InstitutionsUniversity of Bologna
University of Padua
Notable studentsDomenico Guglielmini
Francesco Bianchini
Gianantonio Davia
Luigi Ferdinando Marsili

Geminiano Montanari (1 June 1633 – 13 October 1687) was an Italian astronomer, lens-maker, and proponent of the experimental approach to science. He was a member of various learned academies, notably the Accademia dei Gelati. Montanari's famous students include Domenico Guglielmini, Francesco Bianchini, Gianantonio Davia and Luigi Ferdinando Marsili.

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.