The constellation of Aries, the Ram. Aries is an important autumn constellation for northern observers, lying between Taurus and Pisces, to the south of Andromeda. It is the first constellation of the ancient zodiac because, during the period in which classical mythology was completed (from around 1000 BC until 420 AD), it contained the point at which the Sun's yearly path (the ecliptic) crossed the celestial equator. Owing to the precession or wobble of the Earth's axis, however, this point has since moved into Pisces. The Sun crosses this point on March 21 each year, the vernal equinox, marking the arrival of spring in the northern hemisphere. See "Observing the Constellations" page 24.