The Lunar Nodes
The lunar nodes are represented by a horseshoe symbol. The horseshoe is open on the bottom for the north node and open on the top for the south node.The lunar nodes, north and south, are not real planets. Lunar nodes are points that mark the intersection of the Moon's orbit around the Earth with the ecliptic path. The ecliptic is the illusory path of the Sun as it revolves around the Earth during a year. Actually, it is the Earth's circle around the Sun in the annual orb.The nodes are merely the interception of these two orbit lines. One when the Moon is passing south to north, and the other when Moon is passing north to south.All the planets form nodes but only the Moon's are considered significant enough to be included in horoscopic analysis.
The North Lunar Node is the point at which the interception is made while the Moon is ascending from the south to the north. Hence it is also called the Ascending Node. In Hindu astrology it is called the Dragon's Head . The South Lunar Node is also known as the Descending Node or the Dragon's Tail. These two nodes are always exactly opposite of one another.
When the Sun and Moon are in conjunction, and either lunar node is also in conjunction with both, a solar eclipse occurs. When the Sun and Moon are in opposition, and each is in conjunction with one of the lunar nodes, a lunar eclipse occurs.