Celestial Sphere

From Astrowiki-en

The celestial sphere is an extended projection of the terrestrial globe into outer space. The ecliptic is a line running along the celestial sphere. The projection of the Earth's equator onto the celestial sphere is called the celestial equator, the North and South Poles correspond to the celestial North and South Poles. The celestial sphere's coordinate system corresponds to the one used on Earth: The degrees of longitude find their correspondence in the right ascension, those of latitude in the declination.

The concept of a celestial sphere made it possible to accurately locate the celestial bodies.