What are they?

The Sun and planets do not circle willy-nilly around the Earth. Instead, their apparent path around us inscribes a circle in the skies. This disk-shaped band of the sky is called the ecliptic.

Astrology is geocentric, meaning that even though we realize the Sun does not orbit the Earth, the Earth is at the center of the astrological chart. Thus, Earth is our frame of reference.

The Moon's orbit around the Earth is not the same as the ecliptic. You could visualize them as two giant hula hoops, one inside the other, held at an angle. The Moon's orbit crosses the Ecliptic in two places-- these are called the Moon's Nodes.

The North Node is where the Moon crosses the ecliptic going toward the northern hemisphere, and the South Node is where she crosses the ecliptic headed south. The North Node and the South Node are always directly opposite one another in the sky.

The Moon's Nodes nearly always move in retrograde, meaning they travel backwards through the Zodiac. They make a complete circle through the 12 signs every 18 years.

When the New Moons and Full Moons happen near the Moon's Nodes, eclipses happen. That is because the Earth, Sun, and Moon are lined up so precisely that a shadow is cast.