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io.github.cyanheads/astronomy-mcp-server

io.github.cyanheads/astronomy-mcp-server · v0.4.2

Measured by MCP Station

Description written by the publisher, not verified

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

Connect

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

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

Tools as reported by the server

• astronomy_get_sky_position
  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_get_rise_set
  Compute rise, set, and culmination (transit) times for a body at an observer location, plus the maximum altitude at culmination. For the Sun, also returns the three twilight pairs (civil −6°, nautical −12°, astronomical −18°) so a single call answers "when does the sun set and when is it truly dark.
• astronomy_get_moon_phase
  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_find_events
  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_list_visible
  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
• astronomy_get_ephemeris
  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_satellite_passes
  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

Repository · JSON · Text for agents · Registry updated 2026-10-15