What is Planisphere?
[[File:Planisphere.jpg|thumb]] In [[astronomy]], a '''planisphere''' is a [[Projection (mathematics)|projection]] of the [[celestial sphere]] onto a [[Plane (mathematics)|plane]]. Because of the projection, certain parts of the celestial sphere cannot be shown. [[Hipparchus]] discovered that it was possible to do a projection which keeps the [[Angle|angles]] intact. {{Stub}} [[Category:Astronomy]]