The Lunar Nodes

The two "shadow planets" Rahu, the dragon's head, and Ketu, the dragon's tail, are known in western astrology as the nodes of the moon. These two points in space, for that is what they are, not actual planets at all, are referred to as the North node and South node, respectively. These two points are the places where the path of the orbiting moon crosses the ecliptic, the celestial equator. They always occur on opposite sides of the zodiac from one another. They are eclipse points. If Rahu or Ketu exactly conjuncts either the sun or the moon, there will be a full eclipse. As the ancients considered eclipses to be powerful times, the nodes of the moon have been given the status of planet in Vedic astrology.