CycleCalcs Astronomy is an MCP server with 11 tools an agent can call, among them astro_dark_window, astro_eclipses, astro_find_place. It answers at https://www.cyclecalcs.com/mcp over streamable HTTP, and it listed its tools to an anonymous client, so no sign-in was needed for that. Our probes reached it 10 of 10 times since 4 September 2026; the last check, on 18 October 2026, succeeded.
Read-only astronomy calculations: sun, moon, planets, eclipses, twilight and star positions.
Description as the publisher wrote it.
| Tool | What it does |
|---|---|
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 Inputs: date, nights, moon_illumination_max, lat, lon, place |
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. With a location it adds local circumstances, contact times, and an explicit visible-from-her Inputs: direction, type, count, date, start, end |
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 attributio Inputs: query, id, lat, lon, country, limit |
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 moo Inputs: date, start, end, count, cursor, lat |
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 fa Inputs: date, start, end, count, phases, cursor |
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 assessme Inputs: date, bodies, sort, lat, lon, place |
astro_planet_events | The apparition cycle of the inferior planets as dated events: 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 se Inputs: bodies, kinds, date, start, end, cursor |
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 s Inputs: bodies, date, start, end, step, cursor |
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 ret Inputs: body, date, start, end, search_horizon_days, cursor |
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 "wha Inputs: 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 e Inputs: date, start, end, step, cursor, lat |
Every block below points at https://www.cyclecalcs.com/mcp. Pick your client and copy.
claude mcp add --transport http cyclecalcs-astronomy https://www.cyclecalcs.com/mcp
{
"mcpServers": {
"cyclecalcs-astronomy": {
"command": "npx",
"args": ["-y", "mcp-remote", "https://www.cyclecalcs.com/mcp"]
}
}
}{
"mcpServers": {
"cyclecalcs-astronomy": {
"url": "https://www.cyclecalcs.com/mcp"
}
}
}{
"servers": {
"cyclecalcs-astronomy": {
"type": "http",
"url": "https://www.cyclecalcs.com/mcp"
}
}
}{
"context_servers": {
"cyclecalcs-astronomy": {
"url": "https://www.cyclecalcs.com/mcp"
}
}
}{
"mcpServers": {
"cyclecalcs-astronomy": {
"serverUrl": "https://www.cyclecalcs.com/mcp"
}
}
}{
"mcpServers": {
"cyclecalcs-astronomy": {
"url": "https://www.cyclecalcs.com/mcp"
}
}
}name: CycleCalcs Astronomy
version: 0.0.1
schema: v1
mcpServers:
- name: CycleCalcs Astronomy
type: streamable-http
url: https://www.cyclecalcs.com/mcp{
"mcpServers": {
"cyclecalcs-astronomy": {
"httpUrl": "https://www.cyclecalcs.com/mcp"
}
}
}{
"mcpServers": {
"cyclecalcs-astronomy": {
"type": "http",
"url": "https://www.cyclecalcs.com/mcp"
}
}
}{
"mcpServers": {
"cyclecalcs-astronomy": {
"url": "https://www.cyclecalcs.com/mcp"
}
}
}goose://extension?url=https%3A%2F%2Fwww.cyclecalcs.com%2Fmcp&type=streamable_http&id=cyclecalcs-astronomy&name=CycleCalcs%20Astronomy
It answered our last check on 18 October 2026 in 538 ms. Over 10 checks since 4 September 2026 it answered 10. Status here comes from Neuronto's own probes, not from the publisher.
Yes. It is published by cyclecalcs.com and served from www.cyclecalcs.com, the vendor's own domain: https://www.cyclecalcs.com/mcp.
11, as returned by the server's own tools/list on 10 September 2026: astro_dark_window, astro_eclipses, astro_find_place, astro_moon, astro_moon_phases, astro_planet_board, astro_planet_events, astro_positions, and 3 more.
It answered our last check on 18 October 2026 in 538 ms. Over 10 checks since 4 September 2026 it answered 10.
Put the server under mcpServers in ~/.cursor/mcp.json with the URL https://www.cyclecalcs.com/mcp. The exact JSON is above, with the same setup for Claude Code, Claude Desktop, VS Code, Windsurf, Zed, Gemini CLI and the rest.
It listed its tools to an anonymous client, so reading the tool list needs no key. Individual tools can still ask for credentials in their own inputs.
Publisher: com.cyclecalcs. Endpoint host: www.cyclecalcs.com. ARD identifier: urn:air:com.cyclecalcs:mcp:astronomy.
First indexed 31 August 2026. The tools are exactly what the server returned; nothing on this page
is inferred from its name. Ranking in Neuronto search is never for sale.