Meridian Pointer
From Inventions
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| - | |descrizione= Giacomo Contarini describes it among the inventions of Fabrizio Mordente as an "Inst[rument] f[or] finding the meridian at any time of day without a magnet". The instrument consists of a horizontal disk on which rotates a diopter carrying a triangular plate with a zodiacal belt and an index. The index is positioned at the sign marking the moment of measurement; when the sun | + | |descrizione= Giacomo Contarini describes it among the inventions of Fabrizio Mordente as an "Inst[rument] f[or] finding the meridian at any time of day without a magnet". The instrument consists of a horizontal disk on which rotates a diopter carrying a triangular plate with a zodiacal belt and an index. The index is positioned at the sign marking the moment of measurement; when the sun's ray passes through the openings in the sights, a lighted dot falls on the diopter, indicating the position of the meridian. The instrument was used to construct sundials. |
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Revision as of 10:08, 26 July 2010
Has no specific name.
Contents |
Inventor
Fabrizio Mordente?
Historic Period
ca. 1570
Description
Giacomo Contarini describes it among the inventions of Fabrizio Mordente as an "Inst[rument] f[or] finding the meridian at any time of day without a magnet". The instrument consists of a horizontal disk on which rotates a diopter carrying a triangular plate with a zodiacal belt and an index. The index is positioned at the sign marking the moment of measurement; when the sun's ray passes through the openings in the sights, a lighted dot falls on the diopter, indicating the position of the meridian. The instrument was used to construct sundials.
Bibliographical Resources
Contarini,Giacomo. Figure d'Istromenti Matematici e loro uso, ms, ca. 1590, Oxford, Bodleian Library, Ms. Canon. Ital. 145, c. 19.
Author of the entry: Filippo Camerota
