Celestial Sphere Illuminated Black

Illuminated celestial sphere with a diameter of 32 cm.

A celestial sphere is the imaginary sphere on which the stars are said to be stuck and which surrounds the Earth. Its center is the center of the Earth, but the eye of the Earth observer is specifically taken, given that the radius of the Earth is considered negligible to the radius of the celestial sphere, which is considered almost infinite.

The positions (traces) and movements of the celestial bodies, which are considered to take place on the inner surface of the celestial sphere, are the object of “Global Astronomy”, which is a branch of Astronomy.