Davison Chart

Endpoint POST https://starsapi.com/api/v3/western/compatibility/davison

Overview

Generates a Davison relationship chart. Unlike the composite (which uses midpoints of planet positions), the Davison calculates an actual chart for the midpoint in time and space between two births. The midpoint date, midpoint location, and midpoint time are averaged, then a real natal chart is cast for that moment and place.

The result is a genuine chart with astronomically correct planet positions — not mathematical midpoints. Many astrologers consider it more “real” than the composite.

Authentication

Method	Example
Header (recommended)	`X-Api-Key: am_live_xxxxxxxxxxxx`
Bearer	`Authorization: Bearer am_live_xxxxxxxxxxxx`

Request body

Same person1/person2 nested structure as synastry.

Field	Type	Required	Description
`person1.*`		Yes	Person 1 birth data.
`person2.*`		Yes	Person 2 birth data.
`house_system`	string	No	Default `placidus`.
`node_type`	string	No	Default `true`.

Response shape

Field	Description
`year`, `month`, `day`, `hour`, `minute`	The midpoint date/time calculated from both births.
`latitude`, `longitude`	Midpoint location.
`timezone`	Timezone used.
`planets`	Planet positions for the midpoint chart (real astronomical positions).
`ascendant`	Davison chart Ascendant.
`midheaven`	Davison chart MC.
`house_cusps`	House cusps for the midpoint chart.

Davison vs Composite

Feature	Composite	Davison
Method	Midpoint of each planet pair	Real chart for midpoint date/place
Astronomical reality	Mathematical construct	Actual sky at that moment
Transits	Cannot be transited (not a real chart)	Can be transited (real date exists)
Usage	More common in modern practice	Preferred by many traditional astrologers

Errors

HTTP	Code	Cause
400	`MISSING_FIELD`	Required field absent.
500	`COMPUTE_ERROR`	Midpoint calculation failed.
500	`EPHEMERIS_ERROR`	Computation failed.

# Replace YOUR_API_KEY with the key from your dashboard
curl -X POST "https://starsapi.com/api/v3/western/compatibility/davison" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
        "person1": {
            "year": 1990,
            "month": 5,
            "day": 20,
            "hour": 14,
            "minute": 30,
            "second": 0,
            "latitude": 28.6139,
            "longitude": 77.209,
            "timezone": "Asia/Kolkata"
        },
        "person2": {
            "year": 1992,
            "month": 8,
            "day": 15,
            "hour": 10,
            "minute": 0,
            "second": 0,
            "latitude": 19.076,
            "longitude": 72.8777,
            "timezone": "Asia/Kolkata"
        },
        "house_system": "placidus",
        "node_type": "true"
    }'

const response = await fetch(
  'https://starsapi.com/api/v3/western/compatibility/davison',
  {
    method: 'POST',
    headers: {
      'X-Api-Key': 'YOUR_API_KEY',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      person1: 'Array',
      person2: 'Array',
      house_system: 'placidus',
      node_type: 'true'
    })
  }
);
const result = await response.json();

if (result.success) {
  console.log(result.data);
}

import requests
import os

response = requests.post(
    'https://starsapi.com/api/v3/western/compatibility/davison',
    headers={'X-Api-Key': os.environ['STARSAPI_KEY']},
    json={
        'person1': 'Array',
        'person2': 'Array',
        'house_system': 'placidus',
        'node_type': 'true'
    }
)
result = response.json()

if result['success']:
    print(result['data'])

<?php
$payload = [
    'person1' => 'Array',
    'person2' => 'Array',
    'house_system' => 'placidus',
    'node_type' => 'true',
];

$ch = curl_init('https://starsapi.com/api/v3/western/compatibility/davison');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload));
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'X-Api-Key: ' . getenv('STARSAPI_KEY'),
    'Content-Type: application/json'
]);

$response = curl_exec($ch);
$data = json_decode($response, true);

if ($data['success']) {
    print_r($data['data']);
}

import 'package:http/http.dart' as http;
import 'dart:convert';

Future<Map<String, dynamic>> getAscendant() async {
  final response = await http.post(
    Uri.parse('https://starsapi.com/api/v3/western/compatibility/davison'),
    headers: {
      'X-Api-Key': 'YOUR_API_KEY',
      'Content-Type': 'application/json',
    },
    body: jsonEncode({
      'person1': 'Array',
      'person2': 'Array',
      'house_system': 'placidus',
      'node_type': 'true',
    }),
  );
  return jsonDecode(response.body);
}

import Foundation

func getAscendant() async throws -> [String: Any] {
    var request = URLRequest(url: URL(string:
        "https://starsapi.com/api/v3/western/compatibility/davison"
    )!)
    request.httpMethod = "POST"
    request.setValue("YOUR_API_KEY", forHTTPHeaderField: "X-Api-Key")
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    request.httpBody = """
        {
            "person1": {
                "year": 1990,
                "month": 5,
                "day": 20,
                "hour": 14,
                "minute": 30,
                "second": 0,
                "latitude": 28.6139,
                "longitude": 77.209,
                "timezone": "Asia/Kolkata"
            },
            "person2": {
                "year": 1992,
                "month": 8,
                "day": 15,
                "hour": 10,
                "minute": 0,
                "second": 0,
                "latitude": 19.076,
                "longitude": 72.8777,
                "timezone": "Asia/Kolkata"
            },
            "house_system": "placidus",
            "node_type": "true"
        }
        """.data(using: .utf8)

    let (data, _) = try await URLSession.shared.data(for: request)
    return try JSONSerialization.jsonObject(with: data) as! [String: Any]
}

import okhttp3.*
import org.json.JSONObject

val client = OkHttpClient()
val JSON = "application/json; charset=utf-8".toMediaType()

fun getAscendant(callback: (JSONObject) -> Unit) {
    val payload = """
    {
        "person1": {
            "year": 1990,
            "month": 5,
            "day": 20,
            "hour": 14,
            "minute": 30,
            "second": 0,
            "latitude": 28.6139,
            "longitude": 77.209,
            "timezone": "Asia/Kolkata"
        },
        "person2": {
            "year": 1992,
            "month": 8,
            "day": 15,
            "hour": 10,
            "minute": 0,
            "second": 0,
            "latitude": 19.076,
            "longitude": 72.8777,
            "timezone": "Asia/Kolkata"
        },
        "house_system": "placidus",
        "node_type": "true"
    }
    """.trimIndent()

    val request = Request.Builder()
        .url("https://starsapi.com/api/v3/western/compatibility/davison")
        .addHeader("X-Api-Key", "YOUR_API_KEY")
        .post(payload.toRequestBody(JSON))
        .build()

    client.newCall(request).enqueue(object : Callback {
        override fun onResponse(call: Call, response: Response) {
            callback(JSONObject(response.body!!.string()))
        }
        override fun onFailure(call: Call, e: java.io.IOException) {
            e.printStackTrace()
        }
    })
}

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "net/http"
    "os"
)

func main() {
    payload, _ := json.Marshal(map[string]interface{}{
        "person1": "Array",
        "person2": "Array",
        "house_system": "placidus",
        "node_type": "true",
    })

    req, _ := http.NewRequest("POST",
        "https://starsapi.com/api/v3/western/compatibility/davison",
        bytes.NewBuffer(payload))
    req.Header.Set("X-Api-Key", os.Getenv("STARSAPI_KEY"))
    req.Header.Set("Content-Type", "application/json")

    resp, _ := http.DefaultClient.Do(req)
    defer resp.Body.Close()

    var result map[string]interface{}
    json.NewDecoder(resp.Body).Decode(&result)
    fmt.Println(result["data"])
}

require 'net/http'
require 'json'

uri = URI('https://starsapi.com/api/v3/western/compatibility/davison')
payload = {
  'person1' => 'Array',
  'person2' => 'Array',
  'house_system' => 'placidus',
  'node_type' => 'true'
}

req = Net::HTTP::Post.new(uri)
req['X-Api-Key'] = ENV['STARSAPI_KEY']
req['Content-Type'] = 'application/json'
req.body = payload.to_json

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
res = http.request(req)

data = JSON.parse(res.body)
puts data['data'] if data['success']

200 RESPONSE

{
  "status": 200,
  "success": true,
  "data": {
    "year": 1991, "month": 6, "day": 17,
    "hour": 12, "minute": 15,
    "latitude": 23.845, "longitude": 74.993,
    "timezone": "Asia/Kolkata",
    "planets": { "Sun": { "longitude": 85.7, "sign": "Gemini" } },
    "ascendant": { "longitude": 195.3, "sign": "Libra" },
    "midheaven": { "longitude": 105.8, "sign": "Cancer" },
    "house_cusps": { "1": { "longitude": 195.3 }, "...": "..." }
  },
  "meta": { "endpoint": "/api/v3/western/compatibility/davison", "version": "3.0" }
}