02PrecessionAeons

First, though, let us look at solely the terrestrial equator, or the "tropical" Zodiac. This is the one familiar to us from Astrology as the origins for the names of the months on the gregorian calendar. Here we find such zoomorphs as the half fish, half goat Capricorn, and the sentaur archer Sagittarius. We use these constellations to measure precession using the sun's alignment with them as it "precesses" due to the 23.5° angle of inclination of earth's rotation from its orbital plane.