Meridian Pointer

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Has no specific name.



Fabrizio Mordente?

Historic Period

ca. 1570


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

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