ˈplanə̇ˌsfi(ə)r noun
Etymology: Medieval Latin planisphaerium, from Latin planus flat, plane + sphaera sphere — more at floor , sphere
: a representation of the circles of the sphere on a plane ; especially : a polar projection of the celestial sphere and the stars on a plane with adjustable circles or other appendages for showing celestial phenomena (as the position of the heavens or the time of rising and setting of stars) for any given time
• plan·i·spher·ic | ̷ ̷ ̷ ̷|sfirik, -fer- adjective