Free Self-Discovery Tool
Free sidereal Big 3 calculator: your Sun, Moon and Rising in the tropical and sidereal (Lahiri) zodiacs side by side, with the ayanamsa and your Moon nakshatra. See which of your signs change.
Two thousand years ago the two zodiacs coincided. Since then the equinox point has slid backwards through the constellations, and the tropical zodiac, anchored to the equinox, has slid with it. The sidereal zodiac stayed with the stars. The gap between them, the ayanamsa, is about 24 degrees now, so a tropical placement in the first 24 degrees of a sign lands in the previous sign in sidereal. The calculator shows the gap for your birth date and applies it to your Sun, Moon and Rising.
Sidereal astrology divides the Moon’s path into 27 lunar mansions, the nakshatras, each about 13 degrees wide. Your Moon’s nakshatra is more specific than its sign and is the starting point of Vedic timing. The calculator names yours beside your sidereal Big 3; the full Vedic chart, with its dasha timeline, is one link away.
Often, yes. The sidereal zodiac sits about 24 degrees behind the tropical one, so anyone born in roughly the first 24 degrees of a tropical sign moves back a sign in sidereal. Enter your birth details above and the calculator shows your Sun, Moon and Rising in both systems and marks the ones that change.
The angle between the two zodiacs, caused by the slow precession of the equinoxes. The Lahiri ayanamsa, the standard in Vedic astrology, is about 24 degrees today and grows by roughly one degree every 72 years. The calculator uses the exact value for your birth date.
Both are internally consistent. Tropical astrology is seasonal and Western; sidereal astrology is star-based and the basis of Vedic astrology. The honest approach is to pick one system and read the whole chart in it. The calculator lets you see the same birth in both.