Sidereal (Vedic) chart calculator
The sidereal zodiac measures from the fixed stars rather than the equinox. This shifts every tropical position back by the Lahiri ayanamsa, the offset used in most Vedic astrology. Computed in your browser.
Tropical vs sidereal
Western astrology uses the tropical zodiac, tied to the seasons and beginning at the spring equinox. The sidereal zodiac is tied to the constellations. Precession separates the two by the ayanamsa, now roughly 24°.
This calculator uses the Lahiri (Chitrapaksha) ayanamsa, the official Indian standard. Positions and aspects otherwise match the tropical chart; only the sign boundaries move. See methodology.
Questions
- Why is my sidereal sign different from my usual zodiac sign?
- Most Western sources quote the tropical zodiac. The sidereal zodiac sits about 24 degrees earlier, so any planet in the first 24 degrees of a tropical sign falls in the previous sign here. Only placements in the last six degrees or so keep the same sign in both systems.
- Which ayanamsa does this calculator use?
- Lahiri (Chitrapaksha), the standard adopted by the Indian government for its national ephemeris. The exact value for the birth instant is shown above the chart to four decimal places. Other ayanamsas such as Raman or Krishnamurti differ from Lahiri by up to about a degree and a half and are not offered here.
- Does the ayanamsa change over time?
- Yes. Precession moves the equinox against the stars by roughly one degree every 72 years, so the offset was near 23 degrees in the mid-20th century and is a little over 24 degrees now. The calculator computes it for the birth date rather than using one fixed number.
- Which house system does the sidereal chart use?
- Whole-sign houses counted from the sidereal ascendant sign, which matches the convention of most Vedic chart styles. Aspects between planets are identical to the tropical chart, because shifting every position by the same offset leaves the angles between them unchanged.
Reference, not advice
This is cultural and astronomical reference, not personal prediction or advice.
The sidereal chart applies a precessional offset to the same astronomy. It is a reference construction, not a prediction or personal recommendation.
Last reviewed .