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CycleCalcs Astronomy

com.cyclecalcs/astronomy · v1.1.0

Measured by MCP Station

Description written by the publisher, not verified

Read-only astronomy calculations: sun, moon, planets, eclipses, twilight and star positions.

Connect

claude mcp add --transport http astronomy https://www.cyclecalcs.com/mcp

{
  "mcpServers": {
    "astronomy": {
      "url": "https://www.cyclecalcs.com/mcp"
    }
  }
}

Tools as reported by the server

• astro_sky_today
  One-call snapshot of the whole sky for a place and moment: moon phase and illumination, which planets are up and worth looking at, the next eclipse, and (with a location) sun times. Reach for this first when the question is broad, like "what is in the sky tonight". For solar-day detail use astro_sun
• astro_sun
  The complete solar day for one location: sunrise, sunset, solar noon, day length, civil, nautical and astronomical twilight boundaries, and explicit polar day/night status at high latitudes. Location required. For a series, send start and end (step is whole days, e.g. "1d" or "7d"). For "is it dark
• astro_moon
  The Moon at an instant or as a daily series: phase name and angle, illuminated fraction, distance, apparent size, libration, bright limb, and the next quarter phases. A location adds rise/set and altitude. For a calendar of new and full moons use astro_moon_phases; for the Moon's exact coordinates u
• astro_moon_phases
  Every new moon, quarter and full moon in a window (or the next few from a date): each with its exact instant, distance, apparent size, supermoon classification under both competing definitions, traditional full-moon name, and any eclipse falling on it. Use for "when is the next full moon" and phase
• astro_positions
  Exact positions for up to 20 bodies at an instant or over a time grid: right ascension and declination in both J2000 and of-date frames, ecliptic longitude and latitude, distance, and, with a location, altitude and azimuth with refraction stated per field. With a location the position is topocentric
• astro_rise_set
  Rise, upper transit, set and lower transit for one body at one location, with an explicit status at extreme latitudes (circumpolar, never rises) instead of missing values. Accepts fixed radec targets. For the Sun specifically, astro_sun returns richer twilight structure; for positions between events
• astro_eclipses
  Solar and lunar eclipses: the next or previous from a date, or all in a range, with type, magnitude, obscuration, Saros series and global geometry. A solar eclipse also carries a computed hybrid flag and, when central, the duration, path width and Sun altitude at greatest eclipse. With a location it
• astro_dark_window
  The genuinely dark, moonless observing window for a night: astronomical night intersected with the Moon being down, ranked across up to 62 nights with a trend. The right tool for "when should I stargaze / photograph the Milky Way / observe deep-sky objects". Location required. For plain twilight tim
• astro_planet_board
  All eight planets in one call for a date and optional location: constellation, magnitude, apparent size, elongation from the Sun, morning or evening sky, retrograde state with the next station, rise/set, and a worth-looking-tonight assessment. The right tool for "which planets are visible tonight".
• astro_planet_events
  Dated planet events. For Mercury and Venus, the apparition cycle: inferior and superior conjunctions, greatest eastern and western elongations, peak brightness (a Venus-only event: Mercury's brightness peaks behind the Sun where it cannot be seen), and the rare transits across the Sun; with no dates
• astro_find_place
  Resolve a place name to coordinates, region, country, IANA timezone and a stable place_id, or reverse-look-up the nearest places to a lat/lon. Results are GeoNames data (CC BY 4.0); the response carries the required credit in its attribution field, which must be preserved when results are shown. Not

Tool changes

• 2026-10-24: astro_sky_today, astro_sun, astro_moon, astro_moon_phases, astro_positions, astro_rise_set, astro_eclipses, astro_dark_window, astro_planet_board, astro_planet_events, astro_find_place
• 2026-10-16: astro_sky_today, astro_sun, astro_moon, astro_moon_phases, astro_positions, astro_rise_set, astro_eclipses, astro_dark_window, astro_planet_board, astro_planet_events, astro_find_place

Website · JSON · Text for agents · Registry updated 2026-10-01