"The zodiac is a great circle that intersects the equator at two points, which are the first points of Aries and Libra. One half of this circle inclines to the north, the other inclines to the south. The name derives either from the Greek zodion, that means animal, because it contains the figures of twelve animals in it, or from zoe, meaning life, because the lives of all those on earth are governed by the motion of the planets. In Latin it is called the sign bearer because it has twelve signs in it. It is an oblique circle… In the middle of the zodiac there is a circular line dividing it in two and leaving six degrees on either side. That line is called the ecliptic and no eclipse of the sun or of the moon ever takes place unless both of these bodies pass under that line in the same or in opposite degrees. In the same direction we see an eclipse of the sun, while in the opposite it is an eclipse of the moon. During its movement the sun always passes with its center under the ecliptic and never deviates from it. The rest of the planets and the moon wander from one side to the other." (Cosmographiae introductio, chap. III - Hessler 2008)