Star Ninja's MCP server

MCP is a way to plug extra tools into an AI assistant. Star Ninja is one: connect it once, then ask about any night-sky spot you name.

Connect in Claude or Connect in ChatGPT.

No account, key or sign-up.

The server address

Copy this address:

https://stars.2pm.ninja/mcp

Connect in Claude

Free, Pro, Max, Team and Enterprise plans can add a custom connector. Free allows one.

On Team and Enterprise, an Owner adds it first under Organization settings, then Connectors. You then find it under Customize, then Connectors, and click Connect.

1. In Claude, open Customize, then Connectors.
2. Click + Add, then Add custom connector.
3. Type a name, such as Star Ninja. Paste https://stars.2pm.ninja/mcp.
4. Click Continue.
5. Star Ninja needs no sign-in. Choose No sign in.
6. Click Add.
7. In a chat, click +, then Connectors. Turn on Star Ninja.

Anthropic explains the steps in its guide to custom connectors.

Connect in ChatGPT

Use ChatGPT on the web. Not every ChatGPT plan can add a custom plugin. A workspace admin can also block it. Check OpenAI's help article for your plan.

1. Open ChatGPT Plugins.
2. Select +, then Add custom MCP server.
3. Type a name, such as Star Ninja. Paste https://stars.2pm.ninja/mcp as the Server URL.
4. Set Authentication to No authentication.
5. Select I understand and want to continue.
6. Select Create as a plugin.
7. From your personal plugins, select + to install it.
8. In a chat, type @ and select Star Ninja.

OpenAI explains the steps in its guide to custom MCP servers.

What you get back

For the spot you name, the assistant answers with:

• Darkness — how dark the sky is there.
• Distance — a straight line from your start, with an approximate drive figure.
• Cloud — the cloud forecast for each of the next few nights.
• Moon — the hours each night with no Moon, when they fall, and how lit the Moon is.
• A link — the same start and spot on the map, to open in a browser.

Next steps

To check that it works, ask the assistant:

How dark is the sky at Lahemaa from Tallinn, and when is the Moon down?

It should answer with the darkness, cloud and Moon for that spot.

Open the map to do the same by hand. For what Star Ninja is and isn't, see what Star Ninja is.

Limits

The darkness is a yearly satellite average, not a live reading. The distance is a straight line, and the drive figure is a rough estimate, not a route. Forecasts change.

Star Ninja doesn't rank spots, plan routes or pick one for you. It doesn't check access or safety, and it doesn't guarantee conditions. That judgement stays with you.

Each caller has a rate limit. Calls over it are refused until it clears.