Definition:Celestial Sphere

Definition
The celestial sphere is an imaginary sphere, an indeterminate distance from Earth, which intersects the straight lines from the celestial bodies to the observer.


 * Celestial-Sphere.png

It is then convenient to identify the directions of the celestial bodies with their position on the celestial sphere.

Also see

 * Definition:Celestial Axis
 * Definition:Celestial Equator
 * Definition:Celestial Pole