Definition:Zenith Distance

Definition

Let $X$ be the position of a star (or other celestial body) on the celestial sphere.

The zenith distance $\zeta$ of $X$ is defined as the angle subtended by the the arc of the vertical circle through $X$ between $X$ and the zenith.

Also known as

The zenith distance is also known as the coaltitude.

Also see

• Results about zenith distance can be found here.

Sources

• 1976: W.M. Smart: Textbook on Spherical Astronomy (6th ed.) ... (previous) ... (next): Chapter $\text {II}$. The Celestial Sphere: $18$. Altitude and azimuth.
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): horizontal coordinate system
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): zenith distance (coaltitude)
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): horizontal coordinate system
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): zenith distance (coaltitude)