1. Stars are at different distances from the earth and therefore, being of unequal brightness, they are more or less plain to the sight; many are larger than the bright ones which we see, but being further away they appear small to us.
Chapter 66. On the circular number of the stars.
1. There is a circular number of the stars by which it is said to be known in what time each and every star finishes its orbit, whether in longitude or latitude.[274]
2. For the moon is said to complete its orbit in eight years, Mercury in twenty, Lucifer in nine, the sun in nineteen, Pyrois in fifteen, Phaeton in twelve, Saturn in thirty. When these are finished, they return to a repetition of their orbits through the same constellations and regions.
3. Certain stars being hindered by the rays of the sun become irregular, either retrograde or stationary, as the poet relates, saying:
Sol tempora dividit aevi
Mutat nocte diem, radiisque potentibus astra
Ire vetat, cursusque vagos statione moratur.
Chapter 67. On the wandering stars.
1. Certain stars are called planetae, that is, wandering, because they hasten around through the whole universe with varying motions....