From Inventions

Jump to: navigation, search

Name commonly used since the fifteenth century.



Johannes Mueller, detto Regiomontano

Historic Period



Invented in 1470 by Regiomontanus, the astronomical torquetum is an "exploded" version of the astrolabe, representing the circles of the celestial sphere on different planes: the circle of the ecliptic (inclined), of the equinox (horizontal) and of the meridian (vertical). The instrument served mainly for astronomical computations (converting ecliptic into equinoctial coordinates and vice versa) but could also be used for terrestrial measurements. Undoubtedly, it was the prototype for various instruments developed for surveying and compiling corographic maps, such as the polymeter, the vertical compass, the cosmolabe and the theodolite.

Bibliographical Resources

Regiomontanus, Johannes. Scripta clarissimi mathematici M. Ioannis Regiomontani, De torqueto, astrolabio armillari, regula magna Ptolemaica, baculoque astronomico, et observationibus cometarum, aucta necessariis Ioannis Schoneri Carolostadii additionibus. item Ioannis de Monteregio et Bernardi Waltheri observationes motuum solis, ac stellarum tam fixarum, cumque erraticarum, item libellus Georgii Purbachii de Quadrato geometrico… Norimbergae, apud Ioannem Montanum & Ulricum Neuber, 1544.
Boffito, Giuseppe. Gli strumenti della scienza e la scienza degli strumenti: con l'illustrazione della Tribuna di Galileo. Facsimili di Primo Benaglia. Firenze, Libr. internazionale Seeber, 1929.
Turner, Anthony. Early scientific instruments: Europe 1400-1800. London, Sotheby, 1987.
Kiely, Edmond R. Surveying instruments: their history. Columbus, Carben surveying reprints, 1979.

Links (External) (English) (English) (English) (French)


Author of the entry: Filippo Camerota

Personal tools
In other languages