### Ecliptic Coordinate System

(celestial coordinate system system based upon Earth's orbital plane)

The **Ecliptic Coordinate System** is a
spherical coordinate system used for directions in the
Celestial Sphere,
fixed to the path of the Sun in the sky as seen from Earth,
i.e., the Ecliptic. The name, and the ecliptic are also
used with rectangular coordinates.
Spherical elements:

- Ecliptic (plane)
- Ecliptic latitude
- Ecliptic longitude
- Vernal Equinox (used like the Greenwich Meridian)

In the most usual rectangular system, the X-Y plane is the Ecliptic
and the X axis is the Vernal Equinox. Coordinates are
three dimensional, and indicate a radius (equivalent to
the distance to the object) for which 1 can be used
if distance to the object is not intended to be specified.

(*coordinate system,celestial sphere,Sun,Earth*)
http://en.wikipedia.org/wiki/Equatorial_coordinate_system

**Referenced by:**

Celestial Coordinate System

Ecliptic

Equinox

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