# Secondary Progressions API

Move the natal chart forward symbolically: one ephemeris day of planetary motion stands for one year of life. Give a birth chart and a target date and get back the progressed chart — planets, houses, aspects — for that age. Swiss Ephemeris precision, JSON out.

## Endpoint

`POST /v1/progressions`

- Operation ID: `progressions`
- Cost: 50 credits (tier 3)
- Typical latency: 64 ms, measured against production
- Canonical page: https://api.astroway.info/en/astrology-api/secondary-progressions/

## What it computes

The progressions endpoint applies the classic 'a-day-for-a-year' secondary technique. It takes the natal date, time, UTC offset, and birthplace, measures the elapsed years to your target date, and advances the chart by that many ephemeris days past the birth moment — so age thirty maps to the sky thirty days after birth. It then resolves that progressed moment to a Julian day, pulls the geocentric positions and speeds from the Swiss Ephemeris engine, and returns the progressed planets with their signs and house placements, the house cusps, and the full aspect grid with applying and separating flags and exact orbs. Because the Moon moves about a degree a day, it advances roughly a degree per year of life, making the progressed Moon the fastest-moving and most-watched marker of inner development across the chart.

## When to use it

Use secondary progressions for the slow, internal storyline of a life rather than the day-to-day weather of transits. They suit a 'what's unfolding this year' report, a progressed-Moon phase tracker, an age-milestone feature, or an AI narrative that needs the evolving inner chart at a given point. Where transits describe external timing from the current sky, progressions describe psychological ripening — the chart maturing from the inside. Compute them for a birthday, a turning point, or any age you want to characterise, and feed the progressed placements into interpretation alongside the natal chart and current transits for a layered timing picture. The technique is symbolic, so it answers 'what theme is ripening' better than 'what happens on this exact date'.

## Request parameters

| Parameter | Type | Required | Description |
|---|---|---|---|
| `date` | string (YYYY-MM-DD) | yes | Birth date. |
| `time` | string (HH:MM:SS) | yes | Local clock time at birth. |
| `timezoneOffset` | number (hours) | yes | UTC offset in effect at the birth moment (e.g. 3 for Kyiv summer time). Decimal allowed for half-hour zones. |
| `latitude` | number | yes | Birth-place latitude, decimal degrees (north positive). |
| `longitude` | number | yes | Birth-place longitude, decimal degrees (east positive). |
| `targetDate` | string (YYYY-MM-DD) | yes | Required date to progress the chart to (YYYY-MM-DD); the elapsed years set the day-for-a-year advance. |

## Example request

```bash
curl -X POST https://api.astroway.info/v1/progressions \
  -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,
  "targetDate": "2026-06-15"
}'
```

## Example response

```json
{
  "ok": true,
  "data": {
    "input": {},
    "planets": [
      {
        "name": "Moon",
        "longitude": 312.7,
        "sign": "Aquarius",
        "house": 5
      }
    ],
    "houses": {
      "ascendant": 160.4,
      "mc": 70.1,
      "cusps": [
        "…"
      ]
    },
    "aspects": [
      "…"
    ]
  }
}
```

## Notes

This is the standard secondary, day-for-a-year method, advancing the natal chart one ephemeris day per year of life to the target date. The progressed Moon moves about a degree a year and is the headline marker; outer planets barely shift. Houses follow your chosen system; tropical zodiac and Swiss Ephemeris throughout.

## Related techniques

- https://api.astroway.info/en/astrology-api/transits/
- https://api.astroway.info/en/astrology-api/solar-return/

---

Full machine-readable spec: https://api.astroway.info/v1/openapi.json
Agent instructions: https://api.astroway.info/AGENTS.md