---
title: "Phase Return"
method: POST
path: "/phase-return"
tags: ["Astro-Geography"]
---

# Phase Return

`POST /phase-return`

Find dates when a planet returns to its same synodic phase relative to the Sun (e.g. next Venus heliacal rising, next Mars retrograde station).

## Request body

- PhaseReturn — Birth data for a single natal chart. Required: date (YYYY-MM-DD), time (HH:mm:ss), latitude and longitude in decimal degrees. The short forms lat, lon, lng and tz are rejected with 400 INVALID_FIELD; pass the full names. timezoneOffset is hours from UTC and defaults to 0, meaning UTC. city is a display label only: nothing here geocodes it, so it never stands in for coordinates.
  - `date` string, required
  - `time` string, required
  - `timezoneOffset` number, nullable — Hours from UTC at the given moment, not minutes. Fractional zones are hours too: 5.5 for India, 5.75 for Nepal, -3.5 for Newfoundland. Defaults to 0, meaning UTC.
  - `latitude` number, required
  - `longitude` number, required
  - `houseSystem` string
  - `name` string
  - `city` string
  - `zodiacType` 'tropical' | 'sidereal'
  - `ayanamsaId` number, nullable
  - `ayanamsa` 'fagan-bradley' | 'lahiri' | 'de-luce' | 'raman' | 'krishnamurti' | 'kp' | 'yukteshwar' | 'jn-bhasin' | 'true-citra' | 'djwhal-khul' — Sidereal school by name. Lahiri when omitted. Equivalent to ayanamsaId; send either.
  - `cosmogram` boolean
  - `startYear` number, nullable, required
  - `endYear` number, nullable, required

## Response `200`

Successful calculation

- object
  - `ok` boolean
  - `data` object
    - `planet` string, nullable
    - `phase` string, nullable
    - `returns` object[], nullable
      - `date` string, nullable
      - `longitude` number, nullable

## Other responses

- `400` — Validation error
- `401` — Missing or invalid API key

---

[API](https://skmtc.net/astroway/apis/astroway-calculation-api.md) · [All operations](https://skmtc.net/astroway/apis/astroway-calculation-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/astroway/astroway-calculation-api/revisions/529d7d36d7d6/schema)