Heliocentric Planetary Nodes
In heliocentric astrology, planetary nodes play an important role. These are the intersection points between the orbital planes of the planets. Although the orbits of the planets around the Sun are like rings that do not intersect, the planes of those orbits do intersect. We will soon see why this is important.
Each planet orbits around the Sun on its own orbital plane and each orbital plane has a certain inclination. For instance, the plane of the orbit of the Earth and the plane of the orbit of Mercury do not coincide but are inclined to each other.
- The following image shows the Earth's orbital plane in red and Mercury's orbital plane in black (the inclination in the drawing is actually exaggerated). The nodes are represented by the blue dots, which are the intersection points. The nearest dot is Mercury's North Node (the ascending node) and the dot on the far side is Mercury's South Node (the descending node). When both the Earth and Mercury are near the nodal points, these planets will be in a straight line as viewed from the Sun.
- In geocentric astrology, eclipses play an important role. These occur when the Sun and Moon are in a straight line as viewed from Earth. The same concept is used in heliocentric astrology. When two planets are in a straight line as seen from the Sun, they either:
- share the same zodiacal degree and the same latitude (they are both near the same node)
- are on opposite zodiacal degrees and are at the same latitude (one is near the north node and the other is near the south node)
In both cases, the effect of the conjunction or opposition is greatly strengthened.
- Even if only one of the two planets is near the node, there is an astrological effect. The nodes are sensitive points which 'collect' the energies of both planets. If, for instance, the Earth is on Mercury's North Node (at 18° Taurus), the effect is similar to a conjunction with Mercury (even if Mercury is nowhere near the nodes).
- An astrological effect occurs even when a third planet is on the node. This effect, however, is not very strong. For example, Jupiter may be positioned at 18° Taurus, therefore on the Earth-Mercury North Node. In this case, Jupiter has a slight interaction with both Earth and Mercury.
While nodal points exist for every pair of planets,
the most important nodes in heliocentric astrology are those where the Earth is one of the planets of the pair. This is because, as seen in the lesson
on the Zodiac, the
ecliptic is the Earth's path (orbit) around the Sun and the ecliptic is used as coordinate system to define the twelve signs of the zodiac and the heliocentric position of the planets within the signs.
The very use of an ecliptic-based zodiac suggests that the most important nodes are those between the Earth's orbital plane and those of the other planets.
The following table gives the position of the Earth-planet north node as of January 1st 2000:
Copyright 2006 Maddalena Cecchinato
