---
title: "Transit Calendar"
method: POST
path: "/transit-calendar"
tags: ["Prognostics"]
---

# Transit Calendar

`POST /transit-calendar`

Build a month-by-month transit calendar for a natal chart showing exact dates of aspect ingresses and partile hits.

## Request body

- TransitCalendar — Wrapper { natal: ChartInput } used by endpoints that take a base natal plus extra parameters in flat fields.
  - `natal` ChartInput, required — 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
  - `startDate` string, required
  - `endDate` string, required
  - `maxOrb` number, nullable
  - `aspectAngles` number[]
  - `transitPlanetIds` integer[]

## Response `200`

Successful calculation

- object
  - `ok` boolean
  - `data` object
    - `startDate` string, nullable
    - `endDate` string, nullable
    - `maxOrb` number, nullable
    - `count` number, nullable
    - `events` object[], nullable
      - `jd` number, nullable
      - `date` string, nullable
      - `transitPlanetId` number, nullable
      - `natalPlanetId` number, nullable
      - `aspect` object, nullable
        - `name` string, nullable
        - `i18nKey` string, nullable
        - `angle` number, nullable
        - `orb` number, nullable
        - `symbol` string, nullable
        - `isMajor` boolean, nullable
        - `color` string, nullable
      - `transitLongitude` number, nullable
      - `natalLongitude` number, nullable
      - `isRetrograde` boolean, nullable

## Other responses

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

## Changes

- **2026-08-24** `8ab5a768b521` — 3 info
  - added the optional property `data/events/items/aspect/color` to the response with the `200` status
  - added the optional property `data/events/items/aspect/i18nKey` to the response with the `200` status
  - added the optional property `data/events/items/aspect/orb` to the response with the `200` status
- **2026-08-23** `6828e5609564` — 1 breaking, 3 warning
  - the `allOf[subschema #2]/transitPlanetIds/items/` request property type/format changed from `number`/`` to `integer`/``
  - the `allOf[subschema #2]/aspectAngles/items/` request property's max was set to `360.00`
  - the `allOf[subschema #2]/aspectAngles/items/` request property's min was set to `0.00`
  - the `allOf[subschema #2]/transitPlanetIds/items/` request property's min was set to `0.00`
- **2026-08-18** `dd3764875e7a` — 1 info
  - added the new optional request property `allOf[#/components/schemas/NatalWrapper]/natal/ayanamsa`
- **2026-08-15** `e637d1a9911b` — 2 warning
  - the `allOf[#/components/schemas/NatalWrapper]/natal/timezoneOffset` request property's max was set to `14.00`
  - the `allOf[#/components/schemas/NatalWrapper]/natal/timezoneOffset` request property's min was set to `-14.00`
- …earlier changes not shown

[Full history](https://skmtc.dev/astroway/apis/astroway-calculation-api/changes/transit-calendar/post.md)

---

[API](https://skmtc.dev/astroway/apis/astroway-calculation-api.md) · [All operations](https://skmtc.dev/astroway/apis/astroway-calculation-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/astroway/astroway-calculation-api/revisions/8ab5a768b521/schema)