Zodiac Signs

Definition

The 12 30-degree divisions of the ecliptic — Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, Pisces — each named after a constellation and assigned an element, mode and ruling planet.

Origin

The zodiac was developed by Babylonian astronomer-priests c. 5th century BCE as a 12-fold division of the path the Sun appears to travel through the year. The Hellenistic astrologers of Alexandria added elemental and modal qualities c. 2nd century BCE, codified by Ptolemy in the Tetrabiblos.

Development

Western tropical astrology fixes the signs to the seasonal equinoxes (Aries always begins at the spring equinox). Vedic sidereal astrology fixes them to the actual constellations, which now sit about 24 degrees behind the tropical positions due to precession. Both systems are mathematically valid; they describe different reference frames.

In Practice

A natal chart shows where the Sun, Moon and seven other bodies stood in each of the 12 signs at the moment of birth. The sign of each placement modifies how that planet expresses itself. The signs themselves are not personalities — planets in signs are.

Deeper Reading

Astrologically literate readers stop confusing "sun signs" with the zodiac and recognise that the 12 signs are a coordinate system, not a personality typology. Pop horoscope sun-sign columns reduce a 10-planet chart to a single placement, losing 95% of its information.

See Also

• signs of the zodiac
• astrological signs
• signos del zodiaco