Swiss Ephemeris API Guide: NASA-Grade Calculations

What is Swiss Ephemeris?

Swiss Ephemeris is a high-precision astronomical library developed by Astrodienst as an open-source project. It provides planetary positions with arcsecond accuracy using data from NASA's Jet Propulsion Laboratory (JPL). Vedika API integrates Swiss Ephemeris on our servers, giving you access via simple REST calls without needing local ephemeris files.

Why Use an API?

Get Planetary Positions

// Get planetary positions for a specific moment
const response = await fetch('https://api.vedika.io/v2/astrology/planets', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        'x-api-key': 'YOUR_API_KEY'
    },
    body: JSON.stringify({
        datetime: '2026-01-15T12:00:00Z',
        ayanamsa: 'lahiri' // Optional: for sidereal positions
    })
});

const planets = await response.json();

// Response:
{
    "julianDay": 2460690.0,
    "ayanamsa": 24.1847,
    "planets": [
        {
            "id": 0,
            "name": "Sun",
            "longitude": 294.7823,
            "latitude": 0.0001,
            "distance": 0.9836,
            "speedLongitude": 1.0195,
            "retrograde": false,
            "sign": "Capricorn",
            "signDegree": 24.7823,
            "nakshatra": "Dhanishta",
            "nakshatraPada": 2
        },
        {
            "id": 1,
            "name": "Moon",
            "longitude": 156.4521,
            "latitude": -4.2341,
            "distance": 0.0027,
            "speedLongitude": 13.1765,
            "retrograde": false,
            "sign": "Virgo",
            "signDegree": 6.4521,
            "nakshatra": "Uttara Phalguni",
            "nakshatraPada": 3
        }
        // ... all planets
    ]
}

Supported Celestial Bodies

Ayanamsa Options

// Get positions with different ayanamsa systems
const lahiri = await vedika.planets({
    datetime: '2026-01-15T12:00:00Z',
    ayanamsa: 'lahiri' // Default for Vedic astrology
});

const tropical = await vedika.planets({
    datetime: '2026-01-15T12:00:00Z',
    ayanamsa: 'none' // Western/Tropical zodiac
});

// Supported ayanamsas:
// - lahiri (default)
// - raman
// - krishnamurti (KP)
// - fagan_bradley
// - true_chitra
// - galactic_center
// - none (tropical)

House Calculations

// Get house cusps for a location
const houses = await fetch('https://api.vedika.io/v2/astrology/houses', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        'x-api-key': 'YOUR_API_KEY'
    },
    body: JSON.stringify({
        datetime: '2026-01-15T12:00:00Z',
        latitude: 28.6139,
        longitude: 77.2090,
        houseSystem: 'placidus' // or 'whole_sign', 'equal', 'koch'
    })
});

// Response includes:
// - ascendant
// - midheaven (MC)
// - 12 house cusps
// - vertex
// - part of fortune

Accuracy Comparison