Noun
The representation of the circles of the sphere upon a plane; especially, a representation of the celestial sphere upon a plane with adjustable circles, or other appendages, for showing the position of the heavens, the time of rising and setting of stars, etc., for any given date or hour.
Source: Webster's dictionaryAlthough the Cantino planisphere (1504) and the Ruysch map (1507) clearly delineate the Maldive Islands, giving them the same names, they do not show any islands to the south which can be identified as the Chagos archipelago. Source: Internet
Portuguese cartographer Diego Ribero was the author of the first known planisphere with a graduated Equator (1527). Source: Internet
The planisphere was a star chart invented by Abū Rayḥān al-Bīrūnī in the early 11th century. Source: Internet