Sidereal Astrology Transits API

Use the normal Transits endpoint with one explicit sidereal frame. Both charts are calculated independently at their own dates, then compared in that selected frame.

This is a longitude-coordinate conversion, not a complete Vedic astrology system. It adds no dashas, interpretive rules, scoring, or religious framework.

Endpoint

POST https://api.astroapi.io/api/astro/transits

Sidereal fields

  • Set zodiac to sidereal.
  • ayanamsa accepts lahiri, raman, or krishnamurti.
  • Omitting ayanamsa in sidereal mode defaults to lahiri.
  • All normal transit fields, timezone rules, date limits, errors, and quota behavior still apply.

Example request

{
  "birth": {
    "date": "1990-01-01",
    "time": "12:00",
    "timezone": "UTC",
    "lat": 40.7128,
    "lon": -74.006
  },
  "transitDate": "2025-01-01",
  "transitTime": "12:00",
  "timezone": "UTC",
  "zodiac": "sidereal",
  "ayanamsa": "lahiri"
}

Response contract

The response has the same outer envelope documented in the core Transits guide. Each chart reports zodiac: "sidereal", the selected ayanamsa, sidereal lon, and a preserved tropical_lon. This abbreviated example uses verified engine values. 

{
  "type": "transits",
  "transits": {
    "status": "ok",
    "zodiac": "sidereal",
    "ayanamsa": "lahiri",
    "natal_chart": {
      "zodiac": "sidereal",
      "ayanamsa": "lahiri",
      "planets": {
        "Sun": {
          "lon": 257.0968,
          "tropical_lon": 280.8143,
          "sign": "Sagittarius"
        }
      }
    },
    "transit_chart": {
      "zodiac": "sidereal",
      "ayanamsa": "lahiri",
      "planets": {
        "Sun": {
          "lon": 257.1171,
          "tropical_lon": 281.3234,
          "sign": "Sagittarius"
        }
      }
    },
    "aspects": [
      {
        "transit": "Sun",
        "natal": "Sun",
        "type": "conjunction",
        "exact_angle": 0,
        "distance": 0.0203,
        "orb": 0.0203
      }
    ]
  }
}

Why the separation can change

The engine applies a date-aware ayanamsa to each chart date. Intra-chart angular relationships at one instant are unchanged by a uniform longitude shift, but a natal-to-transit separation across different dates can differ slightly from tropical mode.

Calculation boundary

  • Geocentric apparent planetary positions come from the bundled JPL DE421 ephemeris.
  • The public date window is 1900-01-01 through 2050-12-31.
  • Ayanamsas are date-aware IAU 2006/P03 offsets anchored to their documented J2000 definitions.