The Belt of the Heavens
The zodiac is the circular band of sky — about 16° wide — through which the Sun, Moon, and all classical planets move as seen from Earth. It is divided into twelve signs of 30° each, named after the constellations that once occupied those positions. Every planet's sign placement is defined by where it falls within this belt. Western astrology uses a tropical zodiac fixed to the seasons; Vedic astrology uses the sidereal zodiac fixed to the stars.
The Twelve Signs
| Sign | Element | Modality | Ruler |
|---|---|---|---|
| Aries | Fire | Cardinal | Mars |
| Taurus | Earth | Fixed | Venus |
| Gemini | Air | Mutable | Mercury |
| Cancer | Water | Cardinal | Moon |
| Leo | Fire | Fixed | Sun |
| Virgo | Earth | Mutable | Mercury |
| Libra | Air | Cardinal | Venus |
| Scorpio | Water | Fixed | Mars/Pluto |
| Sagittarius | Fire | Mutable | Jupiter |
| Capricorn | Earth | Cardinal | Saturn |
| Aquarius | Air | Fixed | Saturn/Uranus |
| Pisces | Water | Mutable | Jupiter/Neptune |
Tropical vs. Sidereal Zodiac
The tropical zodiac begins Aries at the vernal equinox — fixed to Earth's seasons. The sidereal zodiac aligns signs with the actual star positions, differing from tropical by roughly 23–24° (the ayanamsa). A person with Sun in Aries tropically may be Pisces in sidereal. Western astrologers use tropical; Vedic astrologers use sidereal. The choice of zodiac fundamentally changes every sign placement and must be stated when discussing planetary positions.