Ecliptic longitude

The ecliptic longitude is λ, β next to the ecliptic latitude, one of the two celestial coordinates of the ecliptic coordinate system.

It is one along the ecliptic - the apparent annual path of the sun on the celestial sphere - from the vernal equinox to the east, so in the same sense as the change in location of the sun runs.

The second coordinate, the width β, is one of the ecliptic in the direction of the Ekliptikpole.

Because the Earth's orbit is not exactly circular, but about a Kepler ellipse with an eccentricity of 1.6 percent, the sun moves not quite uniform among the stars. Your ecliptic longitude changes in winter faster than in summer ( 0.95 to 1.02 ° per day), which causes the so-called equation of time.

The equatorial celestial coordinates right ascension α and declination δ can be ε by means of Spherical Trigonometry and obliquity - with ε ≈ 23.44 ° - in the ecliptic coordinates ( λ, δ ) convert (see small triangle to the right in the diagram ). This coordinate transformation is essential for calculating the orbits of planets and other bodies in the solar system.