Astronomy Mcp Server
by cyanheadscommunityv0.1.3
1
An MCP server that computes offline astronomical data for planets, the Moon, bright stars, and sky events, including positions, rise/set times, phases, eclipses, and visibility. It also offers optional network-backed ephemeris and satellite-pass tools when enabled by configuration.
From the registry: Offline observational astronomy: positions, rise/set, moon phases, eclipses, and seasons.
Install & configure
Prerequisites
- requiredInstall Node.jsNode.js v24 or higher is required to use the portable npx install path.https://nodejs.org/
Install in your client
Paste into the AI you're chatting with — it will figure out the rest
Please install the `astronomy-mcp-server` MCP server into my current AI client (that's you).
Required prerequisites (do these first if not already done):
- **Install Node.js** — Node.js v24 or higher is required to use the portable npx install path. (https://nodejs.org/)
Canonical MCP server config (stdio transport):
- command: `npx`
- args: ["-y","@cyanheads/astronomy-mcp-server@latest"]
- required environment variables:
- `MCP_TRANSPORT_TYPE`: Transport mode for the server. Use "stdio" for MCP client stdio connections. (example: `stdio`)
- optional environment variables:
- `MCP_LOG_LEVEL`: Log level for server logging. (example: `info`)
- `ASTRONOMY_ENABLE_HORIZONS`: Set to "true" to register the astronomy_get_ephemeris tool backed by JPL Horizons. (example: `true`)
- `ASTRONOMY_ENABLE_SATELLITES`: Set to "true" to register the astronomy_get_satellite_passes tool backed by CelesTrak + SGP4. (example: `true`)
- `ASTRONOMY_HORIZONS_BASE_URL`: Override the JPL Horizons API endpoint used by the ephemeris extension. (example: `<your-horizons-api-url>`)
- `ASTRONOMY_CELESTRAK_BASE_URL`: Override the CelesTrak GP/TLE endpoint used by the satellite extension. (example: `<your-celestrak-api-url>`)
- `ASTRONOMY_DEFAULT_TIMEZONE`: Fallback IANA timezone used when a tool call omits timezone. If unset, output is UTC-only. (example: `<your-iana-timezone>`)
- `ASTRONOMY_REQUEST_TIMEOUT_MS`: HTTP timeout in milliseconds for Horizons and CelesTrak requests. (example: `<your-timeout-ms>`)
- `ASTRONOMY_TLE_CACHE_TTL_MS`: In-process TLE cache TTL in milliseconds. (example: `<your-cache-ttl-ms>`)
- `MCP_HTTP_PORT`: Port for HTTP transport. Not needed for stdio, but supported by the server configuration. (example: `<your-port>`)
- `MCP_AUTH_MODE`: Authentication mode: none, jwt, or oauth. (example: `<your-auth-mode>`)
- `LOGS_DIR`: Directory for log files (Node.js only). (example: `<your-logs-directory>`)
- `STORAGE_PROVIDER_TYPE`: Storage backend type. (example: `<your-storage-provider-type>`)
- `OTEL_ENABLED`: Enable OpenTelemetry instrumentation. (example: `true`)
Note: The README also documents Streamable HTTP mode, started locally with MCP_TRANSPORT_TYPE=http and MCP_HTTP_PORT set; endpoint path is /mcp. The simplest portable MCP client configuration is the stdio npx path. No API key is required.
Add this MCP server to my current client's config in the correct format for you. If you need secrets or credentials I haven't provided, ASK me — do not invent values or leave raw placeholders. After adding it, tell me how to verify the server is connected.Note: The README also documents Streamable HTTP mode, started locally with MCP_TRANSPORT_TYPE=http and MCP_HTTP_PORT set; endpoint path is /mcp. The simplest portable MCP client configuration is the stdio npx path. No API key is required.
Tools (7)
astronomy_get_sky_position
Apparent position of one body or named star for an observer and instant, including coordinates and related properties.
astronomy_get_rise_set
Rise, set, and culmination times for a body at a location, including Sun twilight pairs.
astronomy_get_moon_phase
Moon phase for an instant, including illumination, phase name, age, and upcoming quarter phases.
astronomy_find_events
Searches for upcoming sky events such as eclipses, equinoxes, solstices, moon quarters, oppositions, conjunctions, greatest elongations, and apsides.
astronomy_list_visible
Lists currently visible naked-eye bodies, optionally including bright stars, ranked by visibility and conditioned by Sun altitude.
astronomy_get_ephemeris
Gated extension that returns time-series ephemeris for small bodies or spacecraft via JPL Horizons.
astronomy_get_satellite_passes
Gated extension that returns visible satellite passes over an observer using CelesTrak TLE and SGP4.
Environment variables
ASTRONOMY_ENABLE_HORIZONSEnables registration of the JPL Horizons ephemeris tool.ASTRONOMY_ENABLE_SATELLITESEnables registration of the satellite-pass tool.Prerequisites
- • Node.js v24+
Packages
@cyanheads/astronomy-mcp-server
npmv0.1.3transport: stdio
@cyanheads/astronomy-mcp-server
npmv0.1.3transport: streamable-http
Details
- Language
- TypeScript
- License
- Apache-2.0
- Released
- Jun 28, 2026
- Last commit
- Jul 3, 2026
- Registry name
- io.github.cyanheads/astronomy-mcp-server