---
title: "Calculate antiscia and contra-antiscia"
method: POST
path: "/ephemeris/antiscia"
tags: ["ephemeris"]
---

# Calculate antiscia and contra-antiscia

`POST /ephemeris/antiscia`

## Request

- Base URL: `https://api.openephemeris.com`
- URL: `https://api.openephemeris.com/ephemeris/antiscia`
- 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`

Calculate antiscia (mirror points across the Cancer/Capricorn solstice axis) and contra-antiscia for a set of planetary longitudes. Detects hidden conjunctions where one planet's antiscion falls on another planet's natal position. Central to Hellenistic and traditional Western astrology. 🤖 AI-optimized output available — add `format=llm` to reduce payload ~60%.

## Query parameters

- `output_mode` string, nullable
- `format` string

## Headers

- `authorization` string, nullable
- `X-API-Key` string, nullable
- `X-OpenEphemeris-API-Key` string, nullable
- `apikey` string, nullable

## Request body

- AntisciaRequest: Request body for antiscia / contra-antiscia calculation.
  - `bodies` AntisciaBodyInput[], required: Array of body ID + longitude pairs
    - `id` integer, required: Planet/body identifier (0=Sun, 1=Moon, 2=Mercury, etc.)
    - `longitude` number, required: Ecliptic longitude in degrees [0, 360)
  - `orb` number: Orb in degrees for contact detection (default 2.0)

## Response `200`

Successful Response

- AntisciaResponse: Response from antiscia calculation endpoint.
  - `antiscia_points` AntisciaPoint[], required: Antiscion and contra-antiscion for each input body
    - `antiscion_longitude` number, required: Mirror longitude across the Cancer/Capricorn axis
    - `antiscion_sign` string, required
    - `contra_antiscion_longitude` number, required: Opposition point of the antiscion (mirror across Aries/Libra axis)
    - `contra_antiscion_sign` string, required
    - `natal_longitude` number, required: Original ecliptic longitude
    - `natal_sign` string, required
    - `planet_id` integer, required
    - `planet_name` string, required
  - `calculation_metadata` object, required: Metadata about the calculation
  - `contacts` AntisciaContact[], required: Detected antiscia and contra-antiscia conjunctions between bodies
    - `orb` number, required: Angular separation in degrees
    - `planet1` integer, required: ID of the planet whose antiscion / contra-antiscion is involved
    - `planet1_name` string, required
    - `planet2` integer, required: ID of the planet whose natal longitude is conjunct
    - `planet2_name` string, required
    - `type` 'antiscion_conjunction' | 'contra_antiscion_conjunction', required: Type of antiscia contact
  - `success` boolean: Calculation success status

## Other responses

- `400`: Bad Request
- `422`: Unprocessable Entity - Invalid input format
- `500`: Internal Server 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)