Lunar node

The lunar nodes are the points where the moon's orbit crosses the ecliptic. The North (or ascending) node is where the Moon crosses to the North of the ecliptic; the South (or descending) node where it crosses to the South.

The lunar nodes are of major significance in vedic astrology, and are considered to a limited degree in western astrology. Usually only the North node is marked in astrological charts, as the South node is by definition always 180° removed—i.e., located at the exact opposite point in the chart.

Solar eclipses occur when a node coincides with the new moon; lunar eclipses when a node coincides with the full moon.