Log inSubmit server
Astronomy Oracle logo

Astronomy Oracle

by gregario

Query 13,000+ OpenNGC objects and plan observing sessions with local visibility and position calculations.

InstallRepositoryWebsite
Full README Compare alternatives Embed widget Claim this listing

Install Astronomy Oracle

Pick your client, then add it in one click or paste the config.

STDIONode.js
~/Library/Application Support/Claude/claude_desktop_config.json
claude_desktop_config.json
{
  "mcpServers": {
    "gregario-astronomy-oracle": {
      "command": "npx",
      "args": [
        "-y",
        "astronomy-oracle"
      ]
    }
  }
}

Settings → Developer → Edit Config, merge this into mcpServers, then fully quit and reopen Claude Desktop.

Install not yet sandbox-tested— the server itself is confirmed live (we called its tools/list endpoint). The stdio install command is a separate, ongoing check.

Overview

gregario/astronomy-oracle MCP server gives LLM assistants access to the OpenNGC deep-sky catalog and local observing calculations. Its three tools look up objects, filter catalog entries, and create observing plans based on location, date, and visibility criteria. Calculations include altitude, azimuth, rise, transit, and set times using deterministic astronomy math. Reach for it when an agent needs catalog-backed object details or a practical night-sky observing schedule without network access.

Use cases

  • Look up Messier, NGC, IC, or common-name objects
  • Filter targets by magnitude, size, type, or constellation
  • Plan an observing night for a location and date
  • Calculate target altitude, azimuth, rise, transit, and set times

Key features

  • 13,000+ OpenNGC deep-sky objects
  • Deterministic local astronomy calculations
  • Object lookup by designation or common name
  • Catalog search with astronomy filters
  • Observing plans grouped by time window

Tools3

What Astronomy Oracle lets your agent do. Expand a tool for its parameters.

Verified live~760 tokens of context

Security & health

What it can reach and how reliably it runs — from our own checks, not the maintainer’s claims.

ActiveLast checked Today

Recent health check succeeded.

23/24 checks healthy over the last 86d

Supply-chain signal

No high-severity advisories surfaced by our automated scan.

Critical 0High 0Medium 0Low 0

Scanned 15d ago via OSV.dev · astronomy-oracle (npm)

Adoption & maintenance

Factual signals from GitHub, npm, and our automated checks — not a rating.

GitHub stars3Stargazers on the source repository.
npm downloads498Package downloads in the last 30 days.
Last commit3d agoMost recent push to the default branch.
Tools exposed3Callable tools this server registers over MCP.
Directory activity1 installsConfig copies, upvotes, and views on AllMCPs.

How Astronomy Oracle works

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:

Terminal
npx astronomy-oracle

It can also be installed globally with npm:

Terminal
npm install -g astronomy-oracle

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

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

Claude Code can register the same command with:

Terminal
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.

Read the full README View source on GitHub

Reviews

No reviews yet — be the first to share how it worked for you.

Frequently Asked Questions about Astronomy Oracle

gregario/astronomy-oracle is an MCP server that connects AI assistants to the bundled OpenNGC catalog of 13,000+ deep-sky objects. Its main tools look up objects, search and filter catalog entries, and plan observing sessions with local visibility calculations such as altitude, azimuth, rise, transit, and set times.

Install it by running `npx astronomy-oracle`, or install it globally with `npm install -g astronomy-oracle`. The package requires Node.js 18 or later. Claude Desktop and Claude Code can launch it through an `npx -y astronomy-oracle` MCP configuration.

Add an `astronomy-oracle` entry to Claude Desktop’s MCP configuration with `command` set to `npx` and `args` set to `["-y", "astronomy-oracle"]`. After saving the configuration, Claude Desktop can start the server through that command.

No, normal operation does not require an internet connection. The OpenNGC catalog is bundled with the package, and its astronomy calculations run locally.

It uses OpenNGC data covering NGC, IC, Messier, and addendum objects. The catalog includes coordinates, magnitudes, dimensions, surface brightness, object types, and cross-references, and is included under the CC-BY-SA 4.0 license.

Related MCP servers

All in Aerospace & Astrodynamics All alternatives
Add a badge to your READMEShow it’s listed — live SVG, Markdown or HTML.

AllMCPs Directory Badge

Full Badge Customizer

Showcase your server listing on GitHub or your project documentation. Embed this dynamic SVG badge to highlight official listing status and live engagement.

Badge Style:
Live Dynamic SVG PreviewAstronomy Oracle AllMCPs Directory Badge
Markdown (GitHub README)
[![AllMCPs](https://allmcps.com/api/badge/gregario-astronomy-oracle?style=directory)](https://allmcps.com/mcp/gregario-astronomy-oracle)
HTML Embed
<a href="https://allmcps.com/mcp/gregario-astronomy-oracle"><img src="https://allmcps.com/api/badge/gregario-astronomy-oracle?style=directory" alt="Astronomy Oracle on AllMCPs" /></a>