Regular observation of the moon makes it clear. It is elusive. Alluring but elusive. To the human eye, it is constantly moving and this makes the study of it a challenge. At the same time it has patterns that have an amount of predictability to them The apparent span that the moon makes changes from night to night. A full moon in January elevates very high in the sky. One might say overhead. By contrast, a full moon in seems to only get slightly above the horizon