API v3.8.1 · 10 modules (REST + MCP) · 39 MCP tools · independent module semver

Sky data for developers
and AI agents.

Positions, moon phases, rise & set, scientific ephemerides, natal charts and astronomical events — clean JSON over HTTPS, plus a hosted MCP server your agents can call directly.

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Free tier · no credit card

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REST API

53+ endpoints across snapshots, bodies, ephemerides, events, locations and catalogs. A predictable { data, meta } envelope on every call.

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Hosted MCP

39 named tools at mcp.astronomycore.com. Point Cursor or Claude Desktop at it — no local install.

∞

Free to start

Free plan: Ephemeris + Sky modules, 5 credits/day UTC. Pro unlocks all modules.

One request

Ask the sky a question.

Pass a latitude, longitude and time. Get back exactly the fields you asked for — nothing to parse, nothing to compute locally.

~120ms

median response

5044

catalog stars

IAU constellations

moon.sh

curl -H "Authorization: Bearer ac_live_..." \
  "https://api.astronomycore.com/v1/bodies/moon\
   ?latitude=41.9&longitude=12.5"

# → { "phase": "Waxing Gibbous",
#     "illumination": 0.78,
#     "rise": "14:21Z", "set": "01:48Z" }

Platform modules

10 domain packages. One API key.

Each module ships its own npm package, REST routes, and MCP tools — with an independent moduleVersion wire contract. Free tier includes Ephemeris and Sky.

Ephemeris

Free tier

ephemeris · /v1/snapshots

Solar system snapshots, body detail, topocentric ephemeris, observer metadata, and astronomical event search

v2.0.0 · 16 MCP tools

Sky

Free tier

sky · /v1/sky

Hipparcos star catalog, IAU constellations, boundaries, and topocentric sky maps

v1.0.0 · 3 MCP tools

Western Astrology

Pro

westernAstrology · /v1/western-astrology

Natal birth charts — tropical or sidereal, Placidus/Koch/equal/whole sign houses, aspects, lunar nodes, fixed stars, arabic parts, transits, synastry, composite, returns, progressions, void of course

v2.1.0 · 9 MCP tools

Astrocartography

Pro

astrocartography · /v1/astrocartography

Planetary MC/IC/ASC/DSC geographic lines for relocation maps, with optional parans. Overlay tool requires Earth Grid module too.

v1.2.0 · 2 MCP tools

Numerology

Pro

numerology · /v1/numerology

Pythagorean, Chaldean, and Hebrew gematria (Mispar Hechrachi) birth name readings — life path, expression, soul urge, and more

v1.1.0 · 1 MCP tool

Earth Grid

Pro

earthGrid · /v1/earth-grid

Hartmann and Curry local grids plus UVG Becker–Hagens nodes (computed models, not ley lines)

v1.0.0 · 2 MCP tools

Locations

Pro

locations · /v1/locations

Forward and reverse geocoding with batch support and a separate daily quota

v1.0.0 · 2 MCP tools

Galactic Time

Pro

galacticTime · /v1/galactic

Dreamspell / 13 Moon galactic day — kin, wavespell, oracle, and signature by UTC date

v1.0.0 · 1 MCP tool

Chinese Astrology

Pro

chineseAstrology · /v1/chinese-astrology

Chinese zodiac year animal and BaZi four pillars with true solar time (data only, no interpretations)

v1.2.0 · 1 MCP tool

Vedic Astrology

Pro

vedicAstrology · /v1/vedic-astrology

Jyotish sidereal chart with Lahiri or Fagan-Bradley ayanamsa, 27 nakshatras with padas, and Vimshottari dasha