Celestial Equator

celestial equator

If you are standing at the north or south pole, then the celestial equator coincides with your horizon.

At other latitudes, half of the celestial equator is above the horizon, and half is below it.

These are imaginary locations in the sky. The "celestial sphere" is a blanket term for everything beyond the Earth. The celestial equator is the plane of the Earth's equator extended out into space. The "celestial poles" are extensions of the north pole and south pole into space. It's sometimes convenient to describe objects out in space with reference to terrestrial coordinates.