---
title: "Harmonic Chart"
method: POST
path: "/harmonics"
tags: ["Specialized Charts"]
---

# Harmonic Chart

`POST /harmonics`

Calculate a harmonic chart by multiplying all planet longitudes by the given harmonic number (H2–H36).

## Request body

- object

## Response `200`

Successful calculation

- object
  - `ok` boolean
  - `data` object
    - `harmonic` number, nullable
    - `planets` object[], nullable
      - `id` number, nullable
      - `natalLongitude` number, nullable
      - `harmonicLongitude` number, nullable
      - `sign` string, nullable
    - `aspects` unknown[], nullable
      - unknown

## Other responses

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

---

[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/793e5c2dbcdf/schema)