Decan

Each zodiac sign is divided into three decans (also called decanates or faces) of 10 degrees each, creating 36 segments across the zodiac. Each decan has a planetary sub-ruler, adding a secondary layer of meaning to a planet's sign placement. In the Chaldean system, the first decan of Aries is ruled by Mars, the second by the Sun, and the third by Venus, following the traditional planetary order. Early-degree Aries planets feel the purest Mars energy, while late-degree Aries pick up a Venusian undertone -- a subtlety Sun-sign-only astrology misses entirely. Decans explain why two people born under the same sign can feel quite different: a first-decan Scorpio (Mars sub-ruler) has a raw, confrontational edge, while a third-decan Scorpio (Moon sub-ruler) channels that intensity into emotional depth. The Egyptians used decans long before the zodiac signs existed, tracking 36 star groups rising at 10-day intervals. In the dignity system, being in your own decan earns a +1 score.