Planisphere (redirected from Planosphere)

planisphere [′plan·ə‚sfir]

(mapping)

A representation, on a plane, of the celestial sphere, especially one on a polar projection, with means provided for making certain measurements such as altitude and azimuth.

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Planisphere 

the representation of a sphere on a plane in a normal (polar) stereographic projection. The planisphere was used until the 17th century to determine the times of the rising and setting of celestial bodies. It was usually a coordinate grid etched on a metal disk about whose center an alidade that facilitated calculations rotated. The planisphere fell into disuse with the introduction of special tables and nomographs.