What is Sidereal Zodiac?
Unlike the tropical zodiac (used in Western astrology) which is anchored to the seasons, the sidereal zodiac tracks the actual positions of star constellations. Due to the precession of equinoxes, the tropical and sidereal zodiacs drift apart by about 1 degree every 72 years. Currently, the difference (called Ayanamsa) is approximately 24 degrees. This means a planet at 5° Aries tropical is around 11° Pisces sidereal. The Lahiri Ayanamsa is the most widely used correction factor. Vedic astrology exclusively uses the sidereal zodiac for all calculations.