In addition, the orbit of the Moon undergoes two important types of precessional motion: apsidal and nodal.
Since the Moon's axial tilt is only 1.5° with respect to the ecliptic (the plane of Earth's orbit around the Sun), this effect is small.
Once every 18.6 years,[1] the lunar north pole describes a small circle around a point in the constellation Draco, while correspondingly, the lunar south pole describes a small circle around a point in the constellation Dorado.
This is the reason that an anomalistic month (the period the Moon moves from the perigee to the apogee and to the perigee again) is longer than the sidereal month (the period the Moon takes to complete one orbit with respect to the fixed stars).
[citation needed] The precession cycle affects the heights of tides.