Ecliptic longitude
Cross-traditionAstronomical factEditorial synthesis
Definition
How far a body has travelled around the ecliptic, measured in degrees from the vernal equinox. It is the single number every other chart label (sign, degree in sign, house) is derived from.
Also called: Celestial longitude · Longitude (ecliptic)
In more depth
Ecliptic longitude is an angle measured along the ecliptic, starting from the vernal equinox (the point where the ecliptic crosses the celestial equator) and running through a full circle. Latitude, the companion coordinate, measures how far a body sits above or below the ecliptic plane; astrology traditionally works with longitude alone.[1]
Astro Gazer reports this raw longitude in its own column and derives everything else from it. The sign is which twelfth of the circle the longitude falls in; the degree in sign is the remainder within that twelfth. The values come from a published planetary ephemeris rather than from any estimate made in your browser.[2]
References
Numbered citations in the text link to the records below; each record links to the full source registry.
- NASA Science. Basics of Space Flight, Chapter 2: Reference Systems. current (living reference page). Astronomical fact View source record
- Ryan S. Park; William M. Folkner; James G. Williams; Dale H. Boggs. The JPL Planetary and Lunar Ephemerides DE440 and DE441. The Astronomical Journal 161 (3), article 105. 2021. Astronomical fact View source record