Ecliptic

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As seen from the orbiting Earth, the Sun appears to move with respect to the stars. The ecliptic is the yearly path the Sun follows on the celestial sphere. This process repeats itself in a cycle lasting a little over365 days

The ecliptic is the apparent path that the Sun traces out in the sky during the year.[1]

The Sun appears to move against the background of stars because the Earth orbits the Sun.

The ecliptic plane should be distinguished from the invariable plane. That is the average plane of the orbits of the planets. The present ecliptic plane is inclined to the invariable ecliptic plane by about 1.5°.

The name ecliptic is derived from being the place where eclipses occur.

References[change | change source]

  1. United States Naval Observatory Nautical Almanac Office; UK Hydrographic Office, HM Nautical Almanac Office (2008). The Astronomical Almanac for the Year 2010. United States Government Publishing Office. p. M5. ISBN 978-0-7077-4082-9.