Definition:Right Ascension

Definition

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

The right ascension of $P$ is the angular distance measured eastwards along the celestial equator from the vernal equinox.

This is denoted $\alpha$ or $\mathrm {RA}$.

Conventionally, right ascension is measured in units of time rather than angle.

Hence $24$ hours corresponds to $360$ degrees.

Also see

• Results about right ascension can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): equatorial coordinate system
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): right ascension (RA)
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): equatorial coordinate system
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): right ascension (RA)