Predicting an eclipse is easy because all you have to do is keep track of where the Moon crosses the ecliptic.

Question

Quizplus · Accepted Answer

The Moon's orbit around the Earth is tilted with respect to the ecliptic, so it only crosses the ecliptic at two points, called the nodes. Eclipses occur when the Moon is at one of these nodes and is also in line with the Sun. By tracking the Moon's position, astronomers can predict when eclipses will occur.

Predicting an Eclipse Is Easy Because All You Have to Do