Astrool Sidereal Zodiac
A zodiac anchored to the fixed stars, used in Vedic astrology. Today it runs about 24 degrees behind the tropical zodiac.
Definition
The sidereal zodiac (from Latin sidus, "star") keeps the twelve signs aligned with the background stars. It is the zodiac of Vedic astrology and of some Western sidereal astrologers.
Why signs shift
Because of precession, the sidereal zodiac is currently about 24° behind the tropical one. Subtract that from a tropical position and most placements in the first 24° of a sign move back one sign. A tropical Leo Sun at 10° becomes a sidereal Cancer Sun.
Choosing an ayanamsa
Different schools fix the starting star slightly differently. The resulting offset is the ayanamsa; Lahiri is the Indian standard, and Astrool also offers Raman, Krishnamurti and Fagan-Bradley.
See it in your own chart
Astrool calculates your full birth chart, not just your sun sign, and writes your daily, weekly and monthly readings against it.
Common questions
Is the sidereal zodiac more accurate?
It is more accurate to the constellations; the tropical zodiac is accurate to the seasons. They measure different things.
Does sidereal astrology use 13 signs?
No. Both zodiacs use 12 equal signs of 30 degrees. Ophiuchus is a constellation, not a sign.