MCP server

CycleCalcs Astronomy Official

com.cyclecalcs/astronomy

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

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

Website

At a glance

Type

MCP server

Publisher

cyclecalcs.com (verified by the MCP Registry)

Status

Working at last check

Tools

11

Token cost

About 10,038 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 https://www.cyclecalcs.com/mcp

Claude Desktop

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

Codex (config.toml)

[mcp_servers.astronomy]
url = "https://www.cyclecalcs.com/mcp"

Gemini CLI

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

Cursor

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

VS Code

{"servers":{"astronomy":{"type":"http","url":"https://www.cyclecalcs.com/mcp"}}}

Antigravity

agy mcp add astronomy https://www.cyclecalcs.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","server_url":"https://www.cyclecalcs.com/mcp","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"astronomy","server_url":"https://www.cyclecalcs.com/mcp"}

Tools

• astro_dark_window ~619 tokens
  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_eclipses ~1344 tokens
  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_find_place ~419 tokens
  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
• astro_moon ~918 tokens
  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 ~1012 tokens
  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_planet_board ~630 tokens
  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 ~1463 tokens
  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_positions ~1085 tokens
  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 ~1037 tokens
  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_sky_today ~542 tokens
  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 ~969 tokens
  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

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