Vimshottari Dasha API

What is a Vimshottari Dasha API?

A Vimshottari Dasha API returns the 120-year period cycle used in most Vedic practice. It starts from the lord of the janma nakshatra, reduced by however much of that nakshatra the Moon had already travelled at birth, then runs nine mahadashas of fixed length in a fixed order.

Request

Tools are called over MCP, so an assistant connected to https://vedicproof.com/mcp invokes get_databank itself. The arguments it sends are:

{
  "date_of_birth": "1994-01-19",
  "time_of_birth": "05:22",
  "city": "Kochi",
  "country": "India",
  "datasets": [
    "vimshottari_dasha"
  ]
}

Response

Every response carries a plain-language summary string plus structured data, and states the engine and ayanamsa it used. Abridged here for length.

{
  "data": { "vimshottari_dasha": [
    { "lord": "Rahu", "years": 18, "from": "1993-04-02", "to": "2011-04-02" },
    { "lord": "Jupiter", "years": 16, "from": "2011-04-02", "to": "2027-04-02", "running": true }
  ] }
}

What is each mahadasha's length?

How is this calculated and verified?

These are the pinned parameters that affect this computation. The full disclosure, and the golden-chart corpus, live on /proof.

Dasha year length365.2425 days (Gregorian mean year)

Vimshottari periods are measured in mean Gregorian years from the exact birth instant, with the first mahadasha reduced by the elapsed fraction of the janma nakshatra. Engines using a 360-day savana year or a sidereal solar year will differ by days over a lifetime - this parameter is the usual reason two dasha tables disagree.

Rounding and boundariesAssigned on unrounded longitude; displayed to the arc-minute

Rasi, nakshatra and pada are assigned from the full-precision longitude before any rounding, so a graha at 29.9999° stays in its own rasi. Degrees are formatted d° mm' ss" for display only.

Time handlingIANA tzdata via the host Intl database, DST-aware

Offsets are resolved for the birth instant, not for today, so historical DST rules apply wherever the host tzdata carries them. There is no Local Mean Time fallback for births before standard time: a pre-standard-time birth is treated as standard offset. An unknown birth time defaults to 12:00 local and the response flags time_assumed: true and states that the lagna is unreliable.

Common questions

Which year length do you use, and why?

365.2425 days, the mean Gregorian year, so dasha dates line up with the civil calendar a user reads them against. It is stated in the pinned parameters rather than assumed.

How is the starting lord chosen?

By the Moon's nakshatra at birth. The 27 nakshatras cycle through the nine dasha lords three times, so the nakshatra index modulo nine gives the lord.

Does an approximate birth time change the dasha?

Yes, materially. The Moon moves roughly one nakshatra every day, so an hour of error shifts period boundaries by weeks.

Related computations

• Birth Chart API/birth-chart-api
• Dasha API/dasha-api
• Divisional Charts API/divisional-charts-api
• Navamsa API/navamsa-api
• D9 Chart API/d9-chart-api
• Shadbala API/shadbala-api