Definition:Cardinal Points (Celestial)

Definition

The cardinal points of the celestial sphere are the north point, the south point, the east point and the west point:

North Point of Horizon

The point on the celestial horizon through which the principal vertical circle passes is called the north point of the horizon.

South Point of Horizon

The point on the celestial horizon exactly opposite the north point of the horizon is called the south point of the horizon.

East Point of Horizon

Let an observer $O$ be facing the north point of the horizon $N$, facing directly away from the south point of the horizon $S$.

Let the celestial equator meet the celestial horizon at the points $E$ and $W$.

Let $E$ be the point on the right of $O$.

This is called the east point of the horizon.

West Point of Horizon

Let an observer $O$ be facing the north point of the horizon $N$, facing directly away from the south point of the horizon $S$.

Let the celestial equator meet the celestial horizon at the points $E$ and $W$.

Let $W$ be the point on the left of $O$.

This is called the west point of the horizon.

Also see

• Results about celestial cardinal points can be found here.