The basis for division into zones was the two distinct paths of the heavenly bodies: that of the stars and that of the Sun and Moon. Astronomers know today that the Earth revolving around the Sun is tilted on its axis, bringing each hemisphere now closer to the Sun, now further away. The Greeks had the opposite model, that the stars and the Sun rotated around the Earth. The stars moved in fixed circles around the poles. The Sun moved at an oblique angle to the circles, which obliquity brought it now to the north, now to the south. The circle of the Sun was the ecliptic. It was the center of a band called the zodiac on which various constellations were located.