planisphere
/ˈplanɪsfɪə
/noun
A map formed by the projection of a sphere or part of a sphere on a plane, especially an adjustable circular star map that shows the appearance of the heavens at a specific time and place.On the third floor of the Paris Observatory Cassini had laid out a planisphere, a map of the World using an azimuthal projection with the North Pole at the centre....
- Also known as a star wheel, a planisphere is the secret decoder of the sky.
- Emerging from the whitewashed labyrinth of the Stone Town I found myself looking straight onto a pair of large nineteenth century buildings, both built immediately against the flat blue planisphere of the sea.
Derivatives
planispheric
- By far the most popular type is the planispheric astrolabe, on which the celestial sphere is projected onto the plane of the equator.
Origin
Late Middle English planisperie, from medieval Latin planisphaerium, from Latin planus 'level' + sphaera 'sphere'; later influenced by French planisphère.