---
title: "Calculate Draconic Chart"
method: POST
path: "/ephemeris/draconic"
tags: ["ephemeris"]
---

# Calculate Draconic Chart

`POST /ephemeris/draconic`

## Request

- Base URL: `https://api.openephemeris.com`
- URL: `https://api.openephemeris.com/ephemeris/draconic`
- Auth: one of:
  - HTTP bearer
  - API key in header `X-OpenEphemeris-API-Key`
  - API key in header `X-API-Key`
  - API key in header `X-Service-Key`

Calculates draconic chart with True Node as 0 Aries.

## Request body

- DraconicChartRequest
  - `body_ids` integer[]: Optional list of body IDs to compute in the draconic frame. Omit to use the default set [0-11, 15-20] (Sun–Pluto, both North Nodes, Chiron, Pholus and the four main asteroids). Supported extras include -1 (South Node, Mean), -3 (South Node, True), 12/13/40 (Lilith variants) and 21/22 (Vertex / Anti-Vertex, which require subject.birth_location). An unsupported ID is rejected with 422 rather than silently dropped; the set actually computed is echoed in metadata.body_ids.
  - `format` 'json' | 'llm': Response format: json | llm.
  - `include_visual` boolean: If true, also render the draconic chart wheel (every longitude, cusp and angle rotated so the North Node is 0° Aries) as SVG or PNG. Visuals incur a +2 credit surcharge.
  - `subject` SubjectRequest, required: Subject identity and birth data used to compute a chart.
    - `birth_datetime` DateTimeInput, required: Date/time input in ISO-8601, component, or Julian day form. A value that states a clock time must also state its zone, either as a suffix on the string or via the `timezone` field below.
      - `components` object: Date/time components (year, month, day, and optionally hour, minute, second). If hour/minute are present, pass `timezone` alongside them; without it the request is rejected with 400 ambiguous_datetime. Omit the clock entirely and the date resolves to 12:00 UTC.
      - `iso` string: ISO-8601 datetime (supported range 1550–2650 CE, JPL DE440). If it states a clock time it must carry its zone: either a 'Z'/±HH:MM suffix on the string ("1987-07-15T09:01:00-05:00"), or a `timezone` passed alongside it. A zone-less clock time is rejected with 400 ambiguous_datetime — it is not read as UTC. A date-only value ("1987-07-15") has no clock to be ambiguous about and resolves to 12:00 UTC.
      - `julian_day` number, double: Julian Day Number (always UTC-based, so it needs no zone)
      - `timezone` TimezoneInput: Timezone input using IANA names or UTC offsets.
        - `fold_preference` 'earlier' | 'later': Which occurrence to use when the naive local datetime falls in a fall-back fold (a repeated hour): 'earlier' (default — first occurrence) or 'later'. Only meaningful for naive datetimes; the response reports datetime_status=ambiguous_fold either way so the ambiguity can be surfaced to the user.
        - `iana_name` string: IANA timezone name
        - `time_standard` 'auto' | 'standard' | 'daylight': How to interpret a naive local datetime when this zone is applied. 'auto' (default): resolve through the historical-correction overlay where one covers the region/era, then IANA tzdata. 'standard': force the zone's standard (non-daylight) offset — for callers who KNOW the recorded time was standard time regardless of what tzdata believes. 'daylight': force standard+1h. Forcing either marks the resolution tz_confidence=client_override. Ignored when the datetime carries its own Z/±HH:MM suffix or when utc_offset is used.
        - `utc_offset` number: UTC offset in hours
    - `birth_location` BirthLocation, required: Location context for birth data: coordinates plus timezone.
      - `city` string: City name
      - `country` string: Country
      - `elevation` number: Elevation in meters. Accepted and echoed back unchanged; it does not affect planetary positions, which are computed geocentrically. Elevation changes results only where it is taken as the `elev` query parameter: /eclipse/solar/local (local circumstances) and /time/solar-event plus /ephemeris/agro/* (horizon rise/set times).
      - `latitude` CoordinateInput, required: Flexible coordinate input supporting multiple formats.
        - `components` object: Separate degree components with direction
        - `decimal` number: Decimal degrees (-90 to 90 for lat, -180 to 180 for lon)
        - `dms` string: Degrees, minutes, seconds string (e.g., '40°42'46"N')
      - `location_name` string: Birthplace display name (e.g. "Dallas, TX"). Never affects calculations — coordinates and timezone are the only location facts the engine reads. Echoed back verbatim where the response carries an echo block: as subject.location_name on chart routes that echo a subject (natal, draconic, progressed, synastry, natal-transits, overlay, natal/batch items, predictive transit-chart), inside search_summary on /electional/natal-angle-crossings, metadata on /acg/midpoints, and natal on /human-design/transit-chart. Omitted from the response when not sent.
      - `longitude` CoordinateInput, required: Flexible coordinate input supporting multiple formats.
        - `components` object: Separate degree components with direction
        - `decimal` number: Decimal degrees (-90 to 90 for lat, -180 to 180 for lon)
        - `dms` string: Degrees, minutes, seconds string (e.g., '40°42'46"N')
      - `region` string: State/region
      - `timezone` TimezoneInput, required: Timezone input using IANA names or UTC offsets.
        - `fold_preference` 'earlier' | 'later': Which occurrence to use when the naive local datetime falls in a fall-back fold (a repeated hour): 'earlier' (default — first occurrence) or 'later'. Only meaningful for naive datetimes; the response reports datetime_status=ambiguous_fold either way so the ambiguity can be surfaced to the user.
        - `iana_name` string: IANA timezone name
        - `time_standard` 'auto' | 'standard' | 'daylight': How to interpret a naive local datetime when this zone is applied. 'auto' (default): resolve through the historical-correction overlay where one covers the region/era, then IANA tzdata. 'standard': force the zone's standard (non-daylight) offset — for callers who KNOW the recorded time was standard time regardless of what tzdata believes. 'daylight': force standard+1h. Forcing either marks the resolution tz_confidence=client_override. Ignored when the datetime carries its own Z/±HH:MM suffix or when utc_offset is used.
        - `utc_offset` number: UTC offset in hours
    - `gender` string: Gender (optional)
    - `name` string, required: Subject name
    - `notes` string: Additional notes
  - `visual_config` VisualRenderConfig: Optional rendering preferences for inline chart visuals.
    - `format` 'svg' | 'png': Output encoding: "svg" (default) or "png". PNG requires resvg on the server.
    - `layout` 'graph' | 'mandala': Bodygraph composition: "graph" (default) is the classic layout; "mandala" nests the same diagram inside concentric rings. Ignored for wheel renders. Honored on natal and overlay (transit, connection) bodygraph paths.
    - `size` integer: Canvas pixel dimension. Range [200, 4000]. Default 800.
    - `theme` 'light' | 'dark': Colour palette: "light" (default) or "dark".

## Response `200`

Successful Response

- DraconicChartResponse
  - `draconic_positions` DraconicPosition[]
    - `draconic_longitude` number, float
    - `draconic_sign` string
    - `draconic_sign_deg` number, float
    - `id` integer
    - `name` string
    - `natal_longitude` number, float
  - `metadata` object
  - `subject` SubjectResponse: Normalized subject data in response.
    - `altitude` number, required: Altitude in meters
    - `datetime` string, required: ISO format datetime
    - `julian_day` number, double, required: Julian Day Number
    - `latitude` number, required: Latitude in decimal degrees
    - `longitude` number, required: Longitude in decimal degrees
    - `name` string, required: Subject name
    - `timezone_name` string: Timezone name if available
    - `utc_offset` number: UTC offset in hours
  - `success` boolean
  - `visual` VisualResult: Embedded diagram payload returned alongside chart data when include_visual=true.
    - `content_type` string, required: MIME type of the data payload.
    - `credits_charged` integer, required: Additional credits consumed to render the visual: 2, or 0 on a re-render that presented a valid render_token.
    - `data` string, required: Raw SVG string (format=svg) or standard base64-encoded PNG bytes (format=png, no data: URI prefix).
    - `format` string, required: Output format: "svg" or "png".
    - `render_token` string: Short-lived (15 min) token for re-rendering this same chart. Send it back in the X-OE-Render-Token header (or a top-level render_token body field) with a request for the same chart inputs — e.g. the same birth data in a different theme or layout — and that request is not charged again. Bound to your account and to the chart-defining inputs; any other request is charged normally.
    - `type` string, required: Diagram kind: "wheel" or "bodygraph".

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/openephemeris/apis/open-ephemeris-api.md) · [All operations](https://skmtc.dev/openephemeris/apis/open-ephemeris-api/llms.txt) · [OpenAPI document](https://skmtc.dev/openephemeris/apis/open-ephemeris-api/revisions/d195a769cb89?raw)