Vedic Astrology Glossary
The Sidereal-Tropical Offset
Ayanamsa is the angular difference between the tropical (Western) and sidereal (Vedic) zodiacs — approximately 23-24 degrees in 2026. It arises from the slow wobble of Earth's axis (precession of the equinoxes) and explains why your Vedic Sun sign is typically one sign behind your Western Sun sign.
The word ayanamsa (also spelled ayanamsha) means "portion of the path" in Sanskrit. It represents the accumulated divergence between two ways of measuring the zodiac that were once aligned but have drifted apart over millennia.
Two zodiacs, one root: Around 285 CE, the tropical and sidereal zodiacs were approximately aligned — the first point of Aries in both systems coincided. Since then, a slow gravitational wobble in Earth's axis called precession of the equinoxes has caused the tropical zodiac (anchored to the seasons) to drift relative to the actual star constellations. This drift accumulates at approximately 50 arc seconds per year.
By 2026, the two zodiacs are about 23°51′ apart. This means if your Western Sun is at 15° Capricorn, your Vedic (sidereal) Sun is at approximately 21° Sagittarius — a full sign behind.
Why ayanamsa matters: Every planetary position in your Vedic chart is calculated by subtracting the ayanamsa from the tropical position. A 1-degree error in ayanamsa means every planet in your chart is off by 1 degree — which can shift house positions, nakshatra assignments, and in borderline cases, the sign itself.
Lahiri vs. other ayanamsas: Multiple ayanamsa values have been calculated by different scholars. The most widely used is Lahiri ayanamsha (also called Chitrapaksha), officially adopted by the Indian government for astronomical and calendar purposes. Other systems include Raman, Krishnamurti (KP), and Fagan-Bradley (used in Western sidereal astrology). Stellr uses Lahiri by default, consistent with classical Jyotish practice and the Swiss Ephemeris standard.
Effect on your chart: If you've only seen your Western chart, expect most planets to shift one sign back when calculated with Vedic ayanamsa. Your Moon sign, rising sign, and every house cusp will change. Many people find the Vedic placements describe their inner experience more precisely than the tropical equivalents — particularly the Moon sign and rising sign, which carry more weight in Vedic interpretation.
Stellr computes your chart with sub-arcminute precision using Lahiri ayanamsa and Swiss Ephemeris, ensuring your planetary positions are accurate to the standard used by professional Jyotish practitioners.
Ayanamsa is the angular gap between the Western (tropical) zodiac and the Vedic (sidereal) zodiac — currently about 23-24 degrees. Because of this gap, your Vedic Sun sign is typically one sign behind your Western Sun sign. For example, a Western Capricorn (January) is usually a Sagittarius in Vedic astrology. Every planet in your Vedic chart is shifted back by this same amount relative to your Western chart.
Stellr uses the Lahiri ayanamsha (Chitrapaksha ayanamsha), the most widely used system in traditional Jyotish and officially adopted by the Indian government for astronomical calculations. Lahiri is the default standard in Swiss Ephemeris, the planetary calculation engine that powers Stellr's birth chart computations.
The difference is caused by precession of the equinoxes — a slow wobble in Earth's axis that causes the tropical zodiac (fixed to seasons) to drift relative to the actual star constellations. Over roughly 2,000 years, this drift has accumulated to about 23-24 degrees. Vedic astrology uses the sidereal zodiac (aligned to actual stars), so all your planetary positions are shifted back by this amount, often placing your Sun in the previous sign.
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