Definition:Parallel of Altitude

Definition

Let $X$ be a point on the celestial sphere.

Let $LXM$ be a small circle through $X$ which is parallel to the celestial horizon.

Then $LXM$ is a parallel of altitude, and is such that all celestial bodies on it have the same altitude.

Sources

• 1976: W.M. Smart: Textbook on Spherical Astronomy (6th ed.) ... (previous) ... (next): Chapter $\text {II}$. The Celestial Sphere: $18$. Altitude and azimuth.