astronomy-mcp-server: get sky position
astronomy_get_sky_positionCompute 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, apparent magnitude, angular diameter, phase angle, illuminated fraction, angular distance from the Sun, and the constellation it falls in. For a solar-system body it also returns that body card — classification, mean radius, naked-eye visibility — the same values served at astronomy://body/{body}, so a client without resource support does not need a second surface to reach them; a catalog star has no card and the field is absent. Positions are parallax- and aberration-corrected for the given observer; default elevation is 0 m and the default time is now. Supply star (e.g. "Sirius", "Polaris") instead of body to target a catalog star; body is ignored when star is set. Pass an IANA timezone to also receive the observer-local time. This server does not geocode — resolve a place name to latitude/longitude upstream first.
Tool call template
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"latitude": "<latitude>",
"longitude": "<longitude>"
},
"name": "astronomy_get_sky_position"
}
}Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| body | No | Solar-system body to locate. Omit when targeting a named star via `star`. | |
| star | No | Named star to locate, from a bundled catalog of 32 stars — about 30 of the brightest naked-eye stars plus Polaris, not an arbitrary star. Accepts a common name or Bayer designation, with the Greek letter spelled out or as a symbol and the constellation as its genitive or IAU abbreviation (e.g. "Sirius", "Alpha Centauri", "α CMa"). A name outside the catalog fails with the full list of catalog stars. Takes precedence over `body`. | |
| time | No | Instant of observation as an ISO 8601 UTC string, e.g. "2024-04-08T18:00:00Z". Defaults to now. A value with no zone designator is read as UTC, not the local zone of the server process. | |
| latitude | Yes | Observer latitude in decimal degrees, north positive. | |
| timezone | No | IANA timezone for localized output, e.g. "America/Los_Angeles". When omitted, output is UTC-only. | |
| elevation | No | Observer elevation in meters above sea level. Default 0. | |
| longitude | Yes | Observer longitude in decimal degrees, east positive. |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
| body | No | The body or star this position is for, echoed from the request. | |
| error | No | Present when the call failed. Absent on success. | |
| ecliptic | No | Ecliptic-of-date coordinates of the body. | |
| time_utc | No | The instant of the observation in ISO 8601 UTC. | |
| magnitude | No | Apparent visual magnitude (lower is brighter). Null for bodies where the engine cannot compute it. | |
| equatorial | No | Apparent equatorial coordinates, corrected for precession, nutation, parallax, and aberration. | |
| horizontal | No | Refraction-corrected horizontal coordinates as seen from the observer. | |
| time_local | No | The same instant in the observer-local timezone with offset, present only when a timezone was supplied. | |
| body_metadata | No | The body card also served at astronomy://body/{body}, copied here so a client without resource support can reach it. Present for the ten solar-system bodies; absent for a catalog star, which has no card. | |
| constellation | No | The constellation the body currently falls within. | |
| phase_angle_degrees | No | Sun-body-observer phase angle in degrees. Null when not applicable (e.g. stars). | |
| illuminated_fraction | No | Fraction of the disc illuminated, 0 to 1. Null when not applicable. | |
| sun_elongation_degrees | No | Angular distance from the Sun in degrees [0,180], seen from Earth's center. A body within about 15° of the Sun is lost in its glare. 0 for the Sun itself. | |
| angular_diameter_arcsec | No | Apparent angular diameter of the disc in arcseconds. Null for point-source convention bodies. |