Astronomical Ephemeris API

Planetary positions, delivered at the edge

House cusps, fixed stars, and astronomical data via a simple REST API. Sub-arcsecond accuracy from the Swiss Ephemeris, served from 300+ edge locations worldwide.

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Request

curl "https://api.morphemeris.com/v1/positions?\
  dt=2024-04-08T18:18:00Z&\
  bodies=sun,moon" \
  -H "Authorization: Bearer morphemeris_live_..."

200 OK

{
  "data": [
    {
      "body": "sun",
      "longitude": 19.358,
      "latitude": 0.0001,
      "distance": 1.0012,
      "speed": 0.9856,
      "sign": "aries",
      "sign_degree": 19.358,
      "retrograde": false
    },
    {
      "body": "moon",
      "longitude": 25.012,
      "latitude": -3.241,
      "distance": 0.0025,
      "speed": 12.841,
      "sign": "aries",
      "sign_degree": 25.012,
      "retrograde": false
    }
  ],
  "meta": {
    "credits_used": 1,
    "credits_remaining": 999,
    "computation_ms": 0.82
  }
}

Chart the Invisible Architecture of the Sky

Every moment, the planets trace paths that ancient astronomers spent lifetimes cataloging by hand. With one API call, you can resolve those positions to fractions of an arcsecond — the same precision that took Tycho Brahe decades of naked-eye observation to approach.

Build Things That Know Where the Planets Are

A natal chart renderer. A transit alert system that watches the sky and pings you when Saturn crosses your ascendant. An educational app where students drag a slider through centuries and watch the planets dance. A generative art piece driven by the actual geometry of the solar system right now.

Ten Thousand Years of Sky, One Endpoint Away

The Swiss Ephemeris covers 8000 BCE to 8000 CE. That’s every eclipse, every conjunction, every station and retrograde loop for the entirety of recorded human history — and well beyond it. The calculations that once required a room full of ephemeris tables now resolve in under a millisecond at the edge.

Built for Precision and Speed

The Swiss Ephemeris compiled to WebAssembly, running on Cloudflare’s global network. No servers to manage, no cold starts to worry about.

Sub-Arcsecond Accuracy

Swiss Ephemeris data spanning 10,000 years. The same engine trusted by professional astronomers and astrologers worldwide.

Global Edge Deployment

Runs on Cloudflare Workers across 300+ locations. Typical response times under 50 ms from anywhere on Earth.

Complete Coverage

All 22 house systems. 47 ayanamsha methods. 1,500+ fixed stars. Equatorial and ecliptic coordinates. Topocentric corrections.

Simple, Fair Pricing

1,000 free requests every month. After that, $0.01 per request with prepaid credits. No subscriptions, no surprises.

7 Endpoints, One API Key

Everything you need for astronomical calculations. Each endpoint costs 1 credit — no variable pricing, no gotchas.

/v1/positionsPlanetary longitude, latitude, distance, speed

/v1/housesHouse cusps and angles for any location

/v1/chartCombined positions and houses in one call

/v1/starsFixed star positions by name or catalog

/v1/ayanamshaSidereal correction for any ayanamsha system

/v1/delta-tDelta T (TT − UT1) for any date

/v1/sidereal-timeGreenwich sidereal time

Simple, Transparent Pricing

Start free. Pay only when you need more.

Free Tier

per month

1,000 requests per month
All 7 endpoints
60 requests per minute
No credit card required

Get Started Free

Prepaid Credits

$0.01

per request

Buy as many as you need
Credits never expire
300 requests per minute
Auto-top-up available

Start Building

Free tier resets monthly. Paid credits stack on top of the free allowance. Full pricing details

Agent-Friendly

Built for AI Coding Agents

Morphemeris is designed to be discovered and used by AI agents. OpenAPI spec, llms.txt, structured error messages with suggestions, and an MCP server — so your agent can integrate astronomical data without reading a single doc page.

View OpenAPI Spec

Start calculating in under a minute

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