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Philips' Planisphere, ca. 1900. In astronomy, a planisphere (/ ˈ p l eɪ. n ɪ ˌ s f ɪər, ˈ p l æ n. ɪ-/) 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.
A plastic planisphere. The word planisphere (Latin planisphaerium) was originally used in the second century by Ptolemy to describe the representation of a spherical Earth by a map drawn in the plane. [2] Planisphere
Stereographic projection of the world north of 30°S. 15° graticule. The stereographic projection with Tissot's indicatrix of deformation.. The stereographic projection, also known as the planisphere projection or the azimuthal conformal projection, is a conformal map projection whose use dates back to antiquity.
11th century – Planisphere invented by Biruni [7] 11th century – Universal latitude-independent astrolabe invented by Abū Ishāq Ibrāhīm al-Zarqālī (Arzachel) [8] 1023 – Hamedan observatory in Persia; c. 1030 – Treasury of Optics by Ibn al-Haytham (Alhazen) of Iraq and Egypt; 1074–92 – Malikshah Observatory at Isfahan used by ...
Planisphere or Planisphaerium, a 2nd-century AD book by Claudius Ptolemy about mapping the celestial sphere onto a flat plane using the stereographic projection to make a star chart Planispheric astrolabe , a device consisting of a planisphere joined to a dioptra, used for observing stars and performing astronomical calculations
A celestial map by the Dutch cartographer Frederik de Wit, 1670. A star chart is a celestial map of the night sky with astronomical objects laid out on a grid system. They are used to identify and locate constellations, stars, nebulae, galaxies, and planets. [1]
For example, a Mercator map printed in a book might have an equatorial width of 13.4 cm corresponding to a globe radius of 2.13 cm and an RF of approximately 1 / 300M (M is used as an abbreviation for 1,000,000 in writing an RF) whereas Mercator's original 1569 map has a width of 198 cm corresponding to a globe radius of 31.5 cm and an ...
Mercator's 1569 map was a large planisphere, [3] i.e. a projection of the spherical Earth onto the plane. It was printed in eighteen separate sheets from copper plates engraved by Mercator himself. [4]