getMoonPosition

moon-sighting v1.1.1

---

moon-sighting / getMoonPosition

Function: getMoonPosition()

getMoonPosition(date?, lat, lon, elevation?): MoonPosition

Defined in: api/index.ts:539

Compute the Moon's topocentric position (azimuth, altitude, distance) for an observer.

Works WITHOUT a kernel (uses Meeus Ch. 47 approximation). Accuracy: azimuth/altitude ~0.3°, distance ~300 km. For precision crescent work, use getMoonSightingReport() with the DE442S kernel.

Parameters

date?

Date = ...

Date and time to compute position for (default: now)

lat

number

Observer geodetic latitude in degrees (north positive)

lon

number

Observer longitude in degrees (east positive)

elevation?

number = 0

Observer height above WGS84 ellipsoid in meters (default: 0)

Returns

MoonPosition

Topocentric az/alt (degrees), distance (km), parallactic angle (radians)

Example

const pos = getMoonPosition(new Date(), 51.5, -0.1)
console.log(pos.azimuth, pos.altitude)  // e.g. 212.4, 38.1