Longitude of the ascending node

The longitude of the ascending node (☊ or Ω) is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a reference direction, called the origin of longitude, to the direction of the ascending node, measured in a reference plane.^[1]

The longitude of the ascending node, for a heliocentric orbit.

References

1. Parameters Describing Elliptical Orbits, web page, accessed May 17, 2007.