The lunar nodes are the orbital nodes of the Moon, that is, the two points at which the orbit of the Moon crosses the ecliptic. The ascending (or north) node is where the Moon moves into the northern ecliptic hemisphere, while the descending (or south) node is where the Moon enters the southern ecliptic hemisphere.
Eclipses involving the Moon occur only near the lunar nodes. A solar eclipse occurs when the passage of the Moon through a node coincides with the new moon, while a lunar eclipse occurs when the passage coincides with the full moon. A lunar eclipse may occur if the full Moon is within...