Arabic Lots Calculation

What is the Arabic Lots endpoint?

You need traditional Arabic Parts (Lots) calculated for a birth chart. The Arabic Lots endpoint takes birth data and returns fifteen named lots (Fortune, Spirit, Eros, Necessity, Victory, Courage, Basis, Exaltation, Fathers, Mothers, Marriage, Children, Siblings, Enemies) each with its zodiac sign, exact ecliptic degree, house placement, element, and modality.

This endpoint is part of the Natal Chart API.

Why does this endpoint exist?

You are building Hellenistic or traditional astrology features and you need calculated Arabic Lots. Each lot has a different formula derived from planet and angle positions, and most flip between day and night versions based on the Sun's hemisphere. Implementing fifteen formulas with day/night logic is tedious and error-prone. This endpoint runs them all in one call.

What inputs does it need?

You pass standard birth data: API key, full name, date components, time components, gender, place, decimal latitude and longitude, and timezone offset from UTC. The endpoint computes day or night birth automatically based on the Sun's house placement. Authentication uses a Bearer token in the Authorization header.

What does the response data look like?

You get an envelope with status, code, message, and data. Note this differs slightly from other Natal Chart API endpoints, which use a numeric success flag instead. The data array carries fifteen lot objects, each with the same shape used by Planetary Positions: name, exact degree, sign, house, element, and modality.

What does a real response look like?

Below is a slice of the response for a sample birth (24 May 2023, 14:40:43 IST, New Delhi). The full response includes fifteen lots; this slice shows the four most commonly used (Fortune, Spirit, Eros, Necessity) to keep the example readable.

{
  "status": "success",
  "code": 200,
  "message": "Request successful",
  "data": [
    {
      "name": "Lot of Fortune",
      "full_degree": 131.3860236,
      "sign": "Leo",
      "sign_no": 5,
      "longitude": "11:23:10",
      "house": 11,
      "element": "Fire",
      "modality": "Fixed"
    },
    {
      "name": "Lot of Spirit",
      "full_degree": 240.0528872,
      "sign": "Sagittarius",
      "sign_no": 9,
      "longitude": "0:3:10",
      "house": 2,
      "element": "Fire",
      "modality": "Mutable"
    },
    {
      "name": "Lot of Eros",
      "full_degree": 317.86992970000006,
      "sign": "Aquarius",
      "sign_no": 11,
      "longitude": "17:52:12",
      "house": 5,
      "element": "Air",
      "modality": "Fixed"
    },
    {
      "name": "Lot of Necessity",
      "full_degree": 89.04606899999999,
      "sign": "Gemini",
      "sign_no": 3,
      "longitude": "29:2:46",
      "house": 9,
      "element": "Air",
      "modality": "Mutable"
    }
  ]
}

What can you build with this endpoint?

You use Arabic Lots whenever your product targets traditional, Hellenistic, or advanced natal astrology features. The fifteen named lots cover material themes (Fortune, Basis), psychological themes (Spirit, Eros, Courage), and relational themes (Marriage, Children, Siblings, Enemies).

1. Hellenistic chart features. Render Arabic Parts on the wheel chart alongside planets, with separate glyphs and a dedicated "Lots" panel.
2. Lot-based reports. Build dedicated readings for Fortune and Spirit, the two most-used lots in Hellenistic interpretation.
3. Relationship astrology. Surface Lot of Marriage and Lot of Children in compatibility or family-themed UI.
4. Advanced astrology platforms. Cater to traditional astrology learners by exposing the full lot set with calculated positions.

How accurate is the calculation?

You are computing fifteen derived positions, each from a formula involving multiple planets and angles. The Arabic Lots endpoint uses Swiss Ephemeris with NASA JPL ephemeris data for the underlying planet and angle positions, then applies the day-or-night-aware lot formulas. Day/night classification follows the Sun's hemisphere placement at birth.

Each lot's house field follows the same house_system you specified for the rest of the chart (Placidus by default). Birth time precision matters here as much as it does for the Ascendant: the Lot of Fortune formula includes the Ascendant degree, so a wrong birth time will shift Fortune accordingly.

How does this relate to the parent API?

You are extending the standard birth chart with traditional Arabic Parts calculations. This endpoint complements the Natal Chart API by providing the fifteen most-used Arabic Lots as calculated points alongside standard planets.

Planetary Positions returns the bodies and angles needed to compute lots, but not the lots themselves. House Cusps places the lots into houses. Use this endpoint whenever your UI specifically surfaces Arabic Parts content.

Summary

The Arabic Lots endpoint returns fifteen named Hellenistic lots (Fortune, Spirit, Eros, and others) with their exact ecliptic positions, sign and house placements, elements, and modalities. It runs on Swiss Ephemeris with NASA JPL ephemeris data and applies day-or-night-aware formulas automatically. Use it for traditional astrology features, advanced natal-chart platforms, and any UI that needs Arabic Parts content alongside standard planet positions.