---
title: "Firdaria Planetary Periods"
method: POST
path: "/predictive/time-lords/firdaria"
tags: ["predictive"]
---

# Firdaria Planetary Periods

`POST /predictive/time-lords/firdaria`

## Request

- Base URL: `https://api.openephemeris.com`
- URL: `https://api.openephemeris.com/predictive/time-lords/firdaria`
- 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 firdaria (فرادير) — the medieval Persian planetary period system that assigns each of the seven classical planets a fixed number of years as the dominant ruler of life. The 75-year master cycle differs for day births (diurnal) and night births (nocturnal). Each major period is subdivided into seven sub-periods in Chaldean order.

Firdaria operates independently of signs and houses — it is purely a time-based system making it complementary to profections and transits. Think of it as a 75-year program schedule: knowing your current major and sub-period ruler tells you which planetary archetype is most active in your life right now.

🤖 Agent-first endpoint — pure deterministic math, no ephemeris required.

## Query parameters

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

## Request body

- FirdariaRequest: Input for firdaria (planetary period) calculation. Requires the natal birth datetime and whether the native was born during the day (Sun above horizon = diurnal) or at night (nocturnal). The day/night distinction determines which planet begins the 75-year cycle.
  - `birth_datetime` string, date-time, required: Natal birth datetime in ISO 8601 UTC format.
  - `house_system` string: Optional.
  - `is_day_birth` boolean, required: True if the native was born during the day (Sun above the horizon). Determines the diurnal vs nocturnal firdaria sequence. In diurnal charts, the Sun leads; in nocturnal charts, the Moon leads.
  - `latitude` number: Optional. If provided, calculates natal chart to determine ascendant/sect/lots.
  - `longitude` number: Optional.
  - `target_datetime` string, date-time: Date to evaluate the active period for. Defaults to the current date if omitted.

## Response `200`

Successful Response

- FirdariaResponse: Firdaria planetary periods result — active period, current sub-period, and the full 75-year timeline.
  - `all_periods` object[], required: Complete 75-year firdaria timeline with all major periods and their sub-periods.
    - `duration_years` number
    - `end_date` string, date-time
    - `is_active` boolean: True if this is the currently active major period.
    - `planet` string
    - `start_date` string, date-time
    - `sub_periods` object[]
      - `end_date` string, date-time
      - `is_active` boolean
      - `planet` string
      - `start_date` string, date-time
  - `birth_datetime` string: Birth datetime used for the calculation.
  - `current_period` object, required: The major and sub-period active at the target date.
    - `duration_years` number: Duration of the major period in years.
    - `end_date` string, date-time: End of the major period.
    - `planet` string: Major period ruling planet.
    - `start_date` string, date-time: Start of the major period.
    - `sub_period` object: Active sub-period within the current major period.
      - `end_date` string, date-time
      - `planet` string: Sub-period ruling planet.
      - `start_date` string, date-time
  - `is_day_birth` boolean: Whether the native is diurnal (day birth).
  - `output_mode` string, nullable: Output projection mode (json | llm).
  - `success` boolean, required: Whether the calculation succeeded.

## Other responses

- `422`: Unprocessable Entity - Invalid input
- `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)