# gregario/astronomy-oracle [Health: Active]

**Category:** 🚀 Aerospace & Astrodynamics  
**Repository:** https://github.com/gregario/astronomy-oracle  
**GitHub Stars:** 3  
**npm Downloads (last month):** 498  
**Views:** 7  
**Installs:** 1  
**Upvotes:** 0  
**Directory Page:** https://allmcps.com/mcp/gregario-astronomy-oracle

## Description
Accurate astronomical catalog data and observing session planner. 13,000+ deep-sky objects from OpenNGC with deterministic visibility, rise/transit/set, and alt/az calculations. npx astronomy-oracle

## Tools
Capabilities this server exposes over MCP:

- **lookup_object** — Look up a celestial object by Messier number (e.g. M31), NGC/IC designation (e.g. NGC7000), or common name (e.g. Andromeda Galaxy). Optionally compute visibility from a given location and time.
- **search_objects** — Search and filter the celestial object catalog by type, constellation, magnitude, angular size, or catalog membership. Returns a formatted table of matching objects sorted by brightness.
- **plan_session** — Generate an observing session plan for a given location and date. Returns the best celestial objects to observe grouped by time window (evening, midnight, pre-dawn), scored by observability.

## Claude Desktop Quick Installation
Install path detected from listing signals. Uses `npx` (confidence: high):

```json
"mcpServers": {
  "astronomy-oracle": {
    "command": "npx",
    "args": ["-y","astronomy-oracle"]
  }
}
```

## Documentation

## What gregario/astronomy-oracle MCP server does

gregario/astronomy-oracle connects an MCP-compatible assistant to a bundled catalog of more than 13,000 deep-sky objects from OpenNGC. The catalog covers NGC, IC, Messier, and addendum objects, with fields such as coordinates, magnitude, angular size, surface brightness, object type, Hubble type, and cross-references.

It is designed for astronomy questions that benefit from structured catalog data rather than generated estimates. An assistant can identify an object by designation or common name, find objects matching observing criteria, or assemble a location-specific plan for an observing session.

## How it works

All catalog data is packaged with the application, and calculations run locally. The astronomy calculations include Julian dates, sidereal time, equatorial-to-horizontal coordinate conversion, and rise, transit, and set times. Visibility results can be calculated for a supplied latitude, longitude, and date or time.

`plan_session` evaluates candidate objects using observability factors including altitude, magnitude, and angular size. Results are divided into evening, midnight, and pre-dawn groups, making the output suitable for planning a complete night rather than selecting only one target.

## Setup and configuration

The package requires Node.js 18 or later. Run it directly with npx:

```bash
npx astronomy-oracle
```

It can also be installed globally with npm:

```bash
npm install -g astronomy-oracle
```

For Claude Desktop, add an MCP entry that launches `npx` with the package and the `-y` flag:

```json
{
  "mcpServers": {
    "astronomy-oracle": {
      "command": "npx",
      "args": ["-y", "astronomy-oracle"]
    }
  }
}
```

Claude Code can register the same command with:

```bash
claude mcp add astronomy-oracle -- npx -y astronomy-oracle
```

No environment variables are required. Because the catalog is bundled and calculations are local, normal operation does not require a network connection.

## Tools and capabilities

- `lookup_object` accepts a Messier number, NGC or IC designation, or common name. With location and time supplied, it also returns current altitude and azimuth plus rise, transit, and set times.
- `search_objects` filters the catalog by object type, constellation, magnitude range, angular size, and catalog membership. Matching entries are returned in a formatted table ordered by brightness. Supported catalog filters include Messier, Caldwell, NGC, and IC.
- `plan_session` creates a schedule for a specified location and date. Optional constraints include minimum altitude, maximum magnitude, and object types; results are grouped into evening, midnight, and pre-dawn windows and scored by observability.

## Limitations and notes

The catalog data comes from OpenNGC. Its included data is licensed under CC-BY-SA 4.0, while the astronomy-oracle code is released under MIT. Results depend on the location, date, time, and filtering values supplied to the tools.

_Full upstream README: https://allmcps.com/mcp/gregario-astronomy-oracle/readme_