Lahiri Ayanamsa: why Vedic charts can differ
Ayanamsa is the angular offset used to express planetary positions in a sidereal zodiac. When two calculators use different conventions, a planet or Lagna near a boundary can appear in a different sign, Nakshatra or Pada.
What an ayanamsa does
Planetary positions can be expressed against a tropical zodiac tied to the equinox or a sidereal zodiac referenced to the stars. Because of precession, the two frameworks are offset. An ayanamsa specifies the offset applied when converting a tropical longitude into the chosen sidereal framework.
Lahiri Ayanamsa, also called Chitrapaksha, is one widely used sidereal convention. Parashar Jyotisha currently uses Lahiri as the default for its Kundli calculation stack.
Small longitude differences matter near boundaries
Most placements far from a boundary will keep the same sign across small convention differences, even though their displayed degrees differ. This is why comparing only the chart picture can hide the actual source of disagreement.
When two calculators disagree
- Confirm identical birth date, exact time and birthplace.
- Confirm timezone and daylight-saving handling for the historical date.
- Confirm tropical versus sidereal mode.
- Confirm the named ayanamsa.
- Compare the numeric longitude, not only the sign label.
- For Lagna or houses, also compare coordinates and house calculation assumptions.
| Difference | Likely first check |
|---|---|
| Every planet is shifted by a similar amount | Tropical/sidereal mode or ayanamsa |
| Lagna differs but most planets agree | Birth time, timezone, coordinates and time conversion |
| Moon Nakshatra differs near a boundary | Exact Moon longitude, ayanamsa and birth time |
| Dasha start differs | Birth Nakshatra and remaining fraction calculated from the Moon |
| Panchang clock times differ | City, timezone, local sunrise and displayed transition convention |
What Parashar Jyotisha publishes
The Kundli methodology identifies the current astronomical engine and Lahiri default, while the Panchang methodology explains location and sunrise-sensitive calculations. Publishing the convention makes a disagreement diagnosable and allows corrections to be reported with the exact inputs.
Record the setting with the chart
When saving or sharing a chart for comparison, include the birth inputs and the ayanamsa. A screenshot without those details is difficult to audit.
For an issue report, include the page URL, entered city/date/time, expected value and comparison source. Never send passwords, OTPs or payment details.