Harmonic Chart API

Send the birth data and a harmonic number from 2 to 36. The endpoint computes the natal positions, multiplies each longitude by the harmonic, reduces modulo 360, and returns the resulting chart with its own aspect grid. The sample makes the arithmetic visible: the natal Sun at 54.3760 degrees, taken to the fifth harmonic, returns as 271.8801, which is 54.3760 times five with three full circles removed. Because the multiplication compresses the circle, a natal aspect of 360 divided by n becomes a conjunction in the nth harmonic. Quintiles at 72 degrees stack in the fifth, septiles at roughly 51.4 degrees stack in the seventh, and the ninth is the Western analogue of the navamsa. The response carries the harmonic planets, the house frame and the full aspect grid computed on the harmonic positions, so the chart is usable directly rather than needing a second pass.

curl -X POST https://api.astroway.info/v1/harmonics \
  -H "X-Api-Key: aw_live_..." \
  -H "Content-Type: application/json" \
  -d '{
  "date": "1990-05-15",
  "time": "14:30:00",
  "timezoneOffset": 3,
  "latitude": 50.45,
  "longitude": 30.52,
  "houseSystem": "P",
  "harmonic": 5
}'

{
  "ok": true,
  "data": {
    "harmonicNumber": 5,
    "planets": [
      {
        "id": 0,
        "name": "Sun",
        "longitude": 271.8801,
        "isRetrograde": false
      }
    ],
    "houses": { "system": "P", "cusps": [] },
    "aspects": []
  }
}

Reach for harmonics when the natal chart is not showing the pattern you suspect is there. The minor aspect families are the usual reason: quintiles and septiles are easy to miss in a longitude grid and obvious once the harmonic stacks them into conjunctions. It suits a research tool, an advanced chart analyser, or a feature that offers the seasoned user something past the natal wheel. The fifth is the common entry point for creative and skill patterns, the seventh for the inspirational and compulsive family, the ninth for the marriage and dharma reading it shares with Vedic practice. Send the same birth data as your natal call and the harmonic will refer to the same bodies, so both charts can be presented side by side as two views of one nativity.

Longitudes are multiplied by the harmonic and reduced modulo 360; the aspect grid is then computed on the harmonic positions rather than carried over from the natal chart. Harmonics 2 to 36 are accepted. Positions come from the Swiss Ephemeris engine in the tropical zodiac, on the same bodies and house system as the natal endpoints.