Recently, I started to search more about the orbit of the moon, and noticed there are certain periodic patterns or cycles for which I did not find any satisfactory explanation.
It can be noticed that the perigee and apogee are not constant, and have a cycle of ~206 days.
The orbit of the moon also consists of many oscillations of period ~24.8 hours. And they are quite significant, having an amplitude of around 2.5% of the average distance of the moon (384,400km).
What are the main causes of these two cycles?