The orbital nodes are points where an orbit crosses a plane of reference (e.g. the equator for geocentric orbits, the ecliptic for heliocentric orbits ). Nodes do not exist for orbits with inclination equal to zero (equatorial orbits or ecliptic orbits).

There are two nodes: the ascending and descending nodes. The first is where the object moves from the southern hemisphere to the northern, the second is the opposite.

See also

• Ascending node
• Descending node
• Lunar node