MCP server

Astronomy

io.github.cyanheads/astronomy-mcp-server

Checked 26 Oct 2026, 08:29 UTC · Connected to it and listed its tools

Offline observational astronomy: positions, rise/set, moon phases, eclipses, and seasons.

Source

At a glance

Type

MCP server

Publisher

Not verified

Status

Working at last check

Tools

7

Token cost

About 6,569 tokens per request

Sets up in

Claude Code, Claude Desktop, Codex, Gemini CLI, Cursor, VS Code, Antigravity, ChatGPT, OpenAI API, Grok

Last checked

26 Oct 2026, 08:29 UTC

Connect it to your agent

Add to CursorAdd to VS CodeVS Code Insiders

Opens the app, which shows the server and asks you to confirm. For other apps, copy the setup below.

Claude Code

claude mcp add --transport http astronomy-mcp-server https://astronomy.caseyjhand.com/mcp

Claude Desktop

Settings → Connectors → Add custom connector, and paste the URL.

Codex (config.toml)

[mcp_servers.astronomy-mcp-server]
url = "https://astronomy.caseyjhand.com/mcp"

Gemini CLI

{"mcpServers":{"astronomy-mcp-server":{"httpUrl":"https://astronomy.caseyjhand.com/mcp"}}}

Cursor

{"mcpServers":{"astronomy-mcp-server":{"url":"https://astronomy.caseyjhand.com/mcp"}}}

VS Code

{"servers":{"astronomy-mcp-server":{"type":"http","url":"https://astronomy.caseyjhand.com/mcp"}}}

Antigravity

agy mcp add astronomy-mcp-server https://astronomy.caseyjhand.com/mcp

ChatGPT

Settings → Apps & Connectors → Advanced settings: turn on Developer mode, then Create a connector and paste the URL. Which plans can do this varies.

OpenAI API (Responses tools)

{"type":"mcp","server_label":"astronomy-mcp-server","server_url":"https://astronomy.caseyjhand.com/mcp","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"astronomy-mcp-server","server_url":"https://astronomy.caseyjhand.com/mcp"}

Tools

• astronomy_find_events ~1327 tokens
  Search forward from a start time for the next occurrences of one sky-event class, selected by the `event` enum: solar_eclipse, lunar_eclipse, equinox, solstice, moon_quarter, opposition, conjunction, max_elongation, or perigee_apogee. Both eclipse classes take an optional observer (latitude and long
• astronomy_get_ephemeris ~1396 tokens
  Fetch a time-series ephemeris for a small body (asteroid or comet) or spacecraft from JPL Horizons — RA/Dec, distance, and apparent magnitude over a span, optionally with observer-relative altitude/azimuth. This covers objects the in-process major-body set cannot. The designation is passed to Horizo
• astronomy_get_moon_phase ~313 tokens
  Report the Moon phase for an instant: illuminated fraction, phase name, synodic age in days since the new moon, phase longitude (the Moon–Sun ecliptic-longitude difference, 180° at full), and the next four quarter phases (new, first quarter, full, last quarter) with timestamps. Answers "what is the
• astronomy_get_rise_set ~813 tokens
  Compute rise, set, and culmination (transit) times and maximum transit altitude for a body at an observer location. Searches forward from `start` (default now) for `count` daily cycles (default 1), including days without crossings. For the Sun, each cycle carries civil −6°, nautical −12°, and astron
• astronomy_get_satellite_passes ~1265 tokens
  Predict visible passes of a satellite (e.g. the ISS, NORAD 25544) over an observer in the next `days`. Identify the satellite by exactly one of `norad_id` or `name` — supplying both, or neither, is rejected. A few well-known common names resolve directly to their catalog numbers, ignoring case: ISS
• astronomy_get_sky_position ~798 tokens
  Compute the apparent topocentric position of one solar-system body (sun, moon, mercury through neptune, pluto) or a named bright star for an observer location and instant. Returns equatorial (RA/Dec), refraction-corrected horizontal (altitude/azimuth), and ecliptic coordinates, plus distance, appare
• astronomy_list_visible ~657 tokens
  The one-call "what is up right now" answer. For an observer location and instant, iterate every naked-eye solar-system body (and, with include_stars, the bundled bright stars), compute altitude and azimuth, keep those above the horizon, rank them brightest-and-highest first, and attach a plain-langu

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