Orbital node
An orbital node is one of the two points where an inclined
orbit crosses a plane of reference . Nodes do not exist for orbits with
inclination equal to zero .
The
ascending node is where the object moves north from the
southern hemisphere to the northern, the
descending node is where the object moves back south. The
line of nodes is the intersection of the object's orbital plane with the plane of reference, and runs between the ascending and descending nodes.
The symbol of the ascending node is ?, descending node is ?. These are also known as the "Dragon's Head" and the "Dragon's Tail" respectively.
Encyclopedia
An
orbital node is one of the two points where an inclined
orbit crosses a plane of reference . Nodes do not exist for orbits with
inclination equal to zero .
The
ascending node is where the object moves north from the
southern hemisphere to the northern, the
descending node is where the object moves back south. The
line of nodes is the intersection of the object's orbital plane with the plane of reference, and runs between the ascending and descending nodes.
- “north” is designated by the Axis of the Earth, both referring to equator or ecliptic. Reference to other planes will need an adequate definition.
The symbol of the ascending node is ?, descending node is ?. These are also known as the "Dragon's Head" and the "Dragon's Tail" respectively.
The
lunar nodes are subject to lunar precession, which is the gradual shift westward because of the
gravitational pull of the
Sun upon the
Moon.
See also