Add it to Claude Code
claude mcp add astronomy-oracle -- npx -y astronomy-oracleMake your agent remember this setup
astronomy-oracle's config, env vars, and the gotchas you hit — recalled in every future Claude Code, Cursor, and Codex session.
npx conare@latestFree · one command · indexes the sessions already on disk. Set up in the browser instead →
What it does
- Access to over 13,000 deep-sky objects from the OpenNGC catalog
- Deterministic astronomy calculations including Julian dates and sidereal time
- Local alt/az conversion and rise/transit/set time computation
- Zero network dependency with all data bundled locally
Tools 3
lookup_objectLook up a celestial object by designation or name and optionally compute visibility.search_objectsSearch and filter the astronomical catalog by type, constellation, magnitude, and more.plan_sessionGenerate an observing session plan for a given location and date.Try it
Original README from gregario/astronomy-oracle
Astronomy Oracle
Accurate astronomical catalog data and observing session planner for LLM assistants. Stops hallucinated magnitudes, coordinates, and visibility.
Features
- 3 tools for object lookup, catalog search, and observing session planning
- 13,000+ deep-sky objects from the OpenNGC catalog (NGC, IC, Messier, and addendum objects)
- Deterministic astronomy math — Julian dates, sidereal time, alt/az conversion, rise/transit/set times
- Zero network dependency — all data is bundled, all calculations are local
Install
Run directly with npx:
npx astronomy-oracle
Or install globally:
npm install -g astronomy-oracle
Configuration
Claude Desktop
Add to your claude_desktop_config.json:
{
"mcpServers": {
"astronomy-oracle": {
"command": "npx",
"args": ["-y", "astronomy-oracle"]
}
}
}
Claude Code
claude mcp add astronomy-oracle -- npx -y astronomy-oracle
Tool Reference
`lookup_object`
Look up a celestial object by Messier number, NGC/IC designation, or common name. Optionally compute visibility from a given location and time.
{
"name": "lookup_object",
"arguments": {
"name": "M31",
"latitude": 51.5,
"longitude": -0.1,
"date": "2025-06-15T22:00:00Z"
}
}
Returns detailed object data: type, coordinates (RA/Dec), magnitude, angular size, surface brightness, Hubble type, cross-references, and (when location is provided) current altitude/azimuth with rise/transit/set times.
`search_objects`
Search and filter the catalog by type, constellation, magnitude range, angular size, or catalog membership.
{
"name": "search_objects",
"arguments": {
"type": "PN",
"constellation": "Lyr",
"maxMagnitude": 12.0,
"limit": 10
}
}
Returns a formatted table of matching objects sorted by brightness. Supports filtering by object type (Galaxy, Planetary Nebula, Open Cluster, etc.), constellation, magnitude range, minimum angular size, and catalog (Messier, Caldwell, NGC, IC).
`plan_session`
Generate an observing session plan for a given location and date. Returns the best objects to observe grouped by time window.
{
"name": "plan_session",
"arguments": {
"latitude": 40.7,
"longitude": -74.0,
"date": "2025-03-20",
"minAltitude": 20,
"maxMagnitude": 10.0,
"types": ["G", "PN", "GCl"]
}
}
Returns objects grouped into three windows (evening, midnight, pre-dawn), scored by observability based on altitude, magnitude, and angular size.
Data Sources
| Source | License | Description |
|---|---|---|
| OpenNGC | CC-BY-SA 4.0 | NGC/IC/Messier catalog with coordinates, magnitudes, dimensions, and cross-references |
The OpenNGC data is included under the Creative Commons Attribution-ShareAlike 4.0 International License. See the OpenNGC repository for full attribution.
Development
# Run tests
npm test
# Build
npm run build
# Run in development mode (tsx)
npm run dev
# Open MCP Inspector
npm run inspect
License
MIT for code. CC-BY-SA 4.0 for OpenNGC data.