Solar return astrocartography API
Natal astrocartography answers where a chart works. Solar return astrocartography answers where it works this year. The endpoint computes the exact moment the Sun returns to its natal longitude in the year you specify, then maps that chart across the globe as its own set of angular lines.
Solar return astrocartography API
The endpoint first builds the natal chart, then searches for the instant in the requested year at which the transiting Sun reaches the natal solar longitude, to a precision well under a second of arc. It computes the planetary positions for that instant and traces the four angular line families across the world, exactly as the natal astrocartography endpoint does, returning sixty-three lines. Every planet name carries an SR suffix so a client rendering both maps at once cannot confuse a natal Jupiter line with a solar return one. The lines are returned as coordinate pairs in the same shape as /acg, so an existing renderer needs no changes beyond a style for the second layer.
POST/v1/solar-acg
curl -X POST https://api.astroway.info/v1/solar-acg \
-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,
"year": 2026
}'{
"ok": true,
"data": {
"year": 2026,
"lines": [
{
"planet": "Sun (SR)",
"planetId": 0,
"type": "MC",
"coordinates": [[-85, 110.4845], [-84.5, 110.4845], "…"]
}
]
}
}Parameters
| name | type | Required | |
|---|---|---|---|
| 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. |
| latitude | number | yes | Birth-place latitude, decimal degrees. |
| longitude | number | yes | Birth-place longitude, decimal degrees. |
| year | number | yes | Calendar year of the solar return whose map you want. |
When to use it
This is the endpoint behind the single most commercial question in relocation astrology: where should I spend my birthday, and where should I be based this year. Solar return charts are traditionally cast for wherever the person physically is at the return, which makes location a decision rather than a given, and this map is what turns that decision into something a user can see. Build a yearly relocation report, a birthday-trip recommender, or an annual overlay on your existing astrocartography map. Because the underlying return moment changes every year, the result is naturally re-purchasable content rather than a one-off calculation, and it composes directly with /solar-return when the user wants the chart as well as the map.
Notes
Positions come from the Swiss Ephemeris (Astrodienst) compiled to WASM. The return instant is solved against the natal solar longitude in the tropical zodiac; sidereal solar returns are a different technique and are not what this endpoint computes. The map is drawn from the return chart alone, so it is a complete replacement for the natal lines for that year rather than a modification of them. Some schools cast the return for the birthplace instead of the current location; that choice belongs to your interpretation layer, since the line geometry itself is identical either way.
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