Lunar eclipse part 2: lunar orbit precession

Precession is the way in which the axis of a rotation changes orientation. In other words, it's the way in which the axis around which an object spins is itself rotating through space. Watch this lovely film of the Moon rotating around the Earth https://www.youtube.com/watch?v=jWCBhVfeAQU Notice that the Moon always has the same axis of rotation relative to the Earth and that the Moon orbits the Earth at an angle relative to the plane of the the Earth's orbit around the Sun. Despite this fixed orbital angle, the Earth's journey around the Sun moves this axis through 360 degrees during the year. So the Moon stays fixed relative to the Earth but not relative to the Sun. An eclipse of the Moon occurs when the Sun, Earth and Moon are in line. You'll see from the animation that most months the tilted orbit means that when the Moon is behind the Earth it is too high to be in its shadow.