Definition:Hour Circle

Definition

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

The hour circle through $X$ is defined as the great circle passing through both $X$ and the celestial poles.

Also see

• Results about hour circles can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): hour circle
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): hour circle