Ascending node

The longitude of the ascending node is one of the main elements of the orbit, used to mathematically describe the orientation of the orbital plane relative to the reference plane. Defines the angle in the base plane formed between the base direction to the zero point and the direction to the point of the ascending node of the orbit at which the orbit intersects the base plane in the direction from south to north. To determine the ascending and descending node, select some (so-called base) plane containing the attracting center. The ecliptic plane (the movement of planets, comets, asteroids around the Sun), the plane of the planet's equator (the movement of satellites around the planet), etc. are usually used as the base. The zero point is the First point of Aries (the point of the vernal equinox). The angle is measured from the direction to the zero point counterclockwise.

The ascending node is denoted by ☊ or Ω.