CycleCalcs Astronomy
Read-only astronomy calculations: sun, moon, planets, eclipses, twilight and star positions.
| Endpoint | https://www.cyclecalcs.com/mcp (streamable-http) |
|---|---|
| Registry version | 1.1.0 |
| Now | 12 tools · grade F (35) · pin ts_71456f44cdde778d2a2209281ca9d73e · protocol 2025-06-18 |
| First / last listed | 2026-11-02 03:23 UTC / 2026-11-02 03:23 UTC |
| Grade over time | 2026-11-02: F (35), 12 tools |
Is this your server? Own a server? ToolFit hosted watch re-checks it every 24 h ($0.25 per 30 days) or 6 h ($0.60) and sends you an HMAC-signed webhook when its tools or grade change: POST https://api.youraitools.co/toolfit/v1/watch. To opt out, see About & opt-out.
Tools: astro_sky_today astro_sun astro_moon astro_moon_phases astro_positions astro_rise_set astro_eclipses astro_dark_window observing_windows astro_planet_board astro_planet_events astro_find_place
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; for choosing an observing night use astro_dark_window, and for whether tonight's clouds allow it u params: date, lat, lon, place, tz |
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 enough to observe" prefer astro_dark_window; for a broad snapshot prefer astro_sky_today. params: date, start, end, step, cursor, lat, lon, place, tz |
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 use astro_positions. params: date, start, end, count, cursor, lat, lon, place, tz |
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 calendars. For the Moon's state right now use astro_moon. params: date, start, end, count, phases, cursor, lat, lon, place, tz |
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, but tropical_sign and constellation stay geocentric, and meta.conventions.label_origin says so. Us params: bodies*, date, start, end, step, cursor, lat, lon, place, tz |
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 use astro_positions. params: body*, date, start, end, search_horizon_days, cursor, lat, lon, place, tz |
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 adds local circumstances, contact times, and an explicit visible-from-here answer; set visible_only params: direction, type, count, date, start, end, visible_only, include, cursor, lat, lon, place, tz |
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 times use astro_sun; for whether tonight's clouds allow it, use observing_windows. params: date, nights, moon_illumination_max, lat, lon, place, tz |
observing_windows | Is tonight good for observing here, and when? The clear, dark windows of tonight, and of the next nights the hourly cloud forecast covers, for one place: astronomical night with the Moon down (or up, with moon "any"), under the MET Norway cloud forecast. The windows are the ones the CycleCalcs Observing Planner widget draws, and the rule below decides which count; the answer is the /api/observing- params: lat, lon, tz, place, cloudmax, min_minutes, moon |
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". For exact coordinates of specific bodies use astro_positions. params: date, bodies, sort, lat, lon, place, tz |
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 it also reports where each is in its cycle right now: morning star or evening star, the conjunction params: bodies, kinds, date, start, end, cursor, lat, lon, place, tz |
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. Note the other tools accept a place argument directly, so this is only needed to disambiguate a name, f params: query, id, lat, lon, country, limit |
Entries describe changes in tool definitions. They are not statements about a server, its quality or its author. The grade measures how the tool definitions fit model providers (token cost, schema compatibility, confusable names) as scored by the ToolFit engine at the time of the listing. JSON: append .json. Opt-out: how or hello@youraitools.co.