1,296. Secret Wisdom
Hilchos Kiddush HaChodesh 11:4
The method for calculating the moon’s appearance should not be taken lightly just because it is not necessary nowadays. Rather, it contains esoteric and profound wisdom. These calculations are the great mystery of the calendar, known only to great Sages who would not reveal them to just anyone. They were only revealed to scholars possessing the original ordination and great understanding. The fixed calendar that is used nowadays, since there is no court to set the months based on eyewitness testimony, can be grasped even by students in only three or four days.
Hilchos Kiddush HaChodesh 11:5
A secular intellectual or a Torah scholar who has studied Greek wisdom might consider the calculations that the Rambam uses to determine the appearance of the moon and conclude that they are imprecise in certain areas. If so, he should not assume that the Rambam was unaware of this and merely approximating his data. Rather, one should be aware that whenever the Rambam is inexact, it is because his calculations determined that a slight imprecision did not affect the information regarding when the moon would appear. He does not employ a greater level of exactitude than is necessary.