‹‹‹ Vitr. 9.1.4 | Table of Contents | Vitr. 9.1.6 ›››
5As these signs are twelve in number, each occupies a twelfth part of the heaven, and they move continually from east to west: and through them in a contrary course, the moon, Mercury, Venus, the sun itself, Mars, Jupiter and Saturn, as if ascending, pass through the heavens from west to east in different orbits. The moon making her circuit in twenty-eight days and about one hour, and thus returning to the sign from which she departed, completes the lunar month.
5While these signs, twelve in number and occupying each one twelfth part of the firmament, steadily revolve from east to west, the moon, Mercury, Venus, the sun, as well as Mars, Jupiter, and Saturn, differing from one another in the magnitude of their orbits as though their courses were at different points in a flight of steps, pass through those signs in just the opposite direction, from west to east in the firmament. The moon makes her circuit of the heaven in twenty-eight days plus about an hour, and with her return to the sign from which she set forth, completes a lunar month.