planisphere
Sign in to saveAlso known as planar sky sphere, planar sky map, planar sky chart
thumb|right|upright=1.3|Philips' Planisphere, ca. 1900
~8 min read
Encyclopedic overview
8 sectionsContents
- Description
- History
- The star chart
- The upper disc
- Coordinates
- See also
- References
- External links
thumb|right|upright=1.3|Philips' Planisphere, ca. 1900
In astronomy, a planisphere () is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the visible stars for any time and date. It is an instrument to assist in learning how to recognize stars and constellations. The astrolabe, an instrument that has its origins in Hellenistic astronomy, is a predecessor of the modern planisphere. The term planisphere contrasts with armillary sphere, where the celestial sphere is represented by a three-dimensional framework of rings.
Excerpted from Wikipedia’s “planisphere” article, available under the CC BY-SA 4.0 licence.