Definition:Longitude/Celestial

Definition

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

Let $J$ be a great circle on the celestial sphere passing through $P$ and both of the north ecliptic pole and south ecliptic pole.

The celestial longitude $\lambda$ of $P$ is the (spherical) angle (measuring east) that $J$ makes with the vernal equinox.

It ranges from $0$ to $360 \degrees$.

Also known as

The term celestial longitude is also seen as ecliptic longitude.

Also see

• Definition:Celestial Latitude

• Definition:Longitude
  • Definition:Terrestrial Longitude
  • Definition:Galactic Longitude

• Results about celestial longitude can be found here.

Sources

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