Moon Position Map
Live lunar sub-lunar position, azimuth, altitude angle, and moon ground track across the globe.
The Moon Position Map shows the sublunar point—the location where the Moon is directly overhead—plus its altitude and azimuth from any observer coordinates, phase illumination, distance, and a 24-hour ground track.
Live lunar ephemeris
Moon Position Map
Observer preset: Doha, Qatar
-19.72878°
141.50950°
±12 hours, 30-minute steps
Purple marker: point on Earth where the Moon is at the zenith. Amber marker: observer. Purple line: calculated sublunar ground track. Map tiles © OpenStreetMap contributors.
Moon Position Technical Specifications & Standards
WGS84 observer coordinates; IAU astronomical reference frames and Earth rotation implemented by Astronomy Engine
Standard global ellipsoidal coordinate reference system
Geocentric Geodesics
Displayed to 0.01° for observer angles and 0.00001° for the computed sublunar coordinates; practical visibility is limited by terrain, refraction, weather, and device-coordinate accuracy.
GeoJSON · KML · CSV · SVG
Compatible with QGIS, ArcGIS, Google Earth & CAD
100% Client-Side
Calculations run in-browser. Zero coordinate logging.
How to Use the Moon Position Map
Follow this step-by-step procedure to execute precise spatial measurements and export results.
- 1Choose a date and time: Use the current moment or select a local observation date and time.
- 2Set the observer: Enter latitude and longitude or use browser geolocation; coordinates are processed locally.
- 3Read the observer angles: Altitude states how high the Moon is above the horizon and azimuth gives its compass bearing clockwise from north.
- 4Explore the global track: Use the purple marker for the sublunar point and the purple line for its calculated ±12-hour ground track.
Geodesic Precision vs. Competitor Mapping Approaches
Most legacy mapping utilities (such as CalcMaps and FreeMapTools) rely on planar Web Mercator projections or spherical approximations, causing significant mathematical distortion at higher latitudes. GeoMap Suite computes exact ellipsoidal geodesics on the WGS84 reference ellipsoid.
| Calculation Model | Mathematical Basis | Distortion on WGS84 | Standard Tools | Practical Application |
|---|---|---|---|---|
| Planar (Web Mercator) | Cartesian dx² + dy² | 10% to 200%+ error | CalcMaps / Simple map tools | Distorts drastically away from equator. Inaccurate for true distance. |
| Spherical Great-Circle | Haversine (R = 6,371 km) | Up to 0.5% (~5 km/1,000 km) | Basic Google Maps wrappers | Ignores Earth's polar flattening. Reasonable for rough estimates. |
| GeoMap Suite Ellipsoidal | Karney Direct/Inverse WGS84 | < 15 nanometers (<0.0001%) | GeoMap Suite | Geodetic surveying, maritime, flight paths & legal boundary analysis. |
Is the Moon visible from Doha?
An observer wants the Moon’s direction and next rise or set event from Doha.
Input Parameters
- Observer
- 25.2854° N, 51.5310° E
- Time
- Current local time
Computed Outputs
- Altitude
- Calculated for the selected instant
- Azimuth
- Degrees clockwise from true north
Step-by-Step Mathematical Process
- Enter the coordinates.
- Select the current time.
- Check whether altitude is positive.
- Use azimuth as the compass direction.
Locate the sublunar point
A geography class wants to find where the Moon is at the zenith.
Input Parameters
- Observer
- Any valid coordinate
- Time
- Selected UTC instant
Computed Outputs
- Sublunar point
- Latitude and longitude
Step-by-Step Mathematical Process
- Set the time.
- Read the purple marker coordinates.
- Follow the ground track across the map.
Understanding Your Results & Practical Interpretation
Sublunar point
The terrestrial point where the Moon is at 90° altitude at that instant. It moves continually as Earth rotates and the Moon advances in orbit.
Altitude and azimuth
Altitude is measured from the horizon (0°) to the zenith (90°); negative altitude means the Moon is below the ideal horizon. Azimuth is measured clockwise from true north.
Illumination and distance
Illumination is the visible fraction of the lunar disk. Distance is the topocentric observer-to-Moon distance and varies through the Moon’s elliptical orbit.
Practical Applications & Real-World Use Cases
Night-sky planning
Check lunar bearing, elevation, phase brightness, and rise/set timing before an observing session.
Earth science education
Relate right ascension, declination, Earth rotation, phases, and the moving sublunar point.
Outdoor operations
Estimate natural moonlight direction and timing while accounting for local horizon limitations.
Mathematical Methodology & Geodetic Accuracy
Geocentric Lunar Ephemeris and Topocentric Horizontal Coordinates
Astronomy Engine calculates the Moon’s geocentric vector, rotates it to the true equator of date, and converts right ascension and declination to the terrestrial sublunar point. Observer altitude and azimuth include topocentric lunar parallax and normal atmospheric refraction.
λsub = 15° × (RAmoon − GAST); φsub = DecmoonLimitations & Boundary Conditions
- •Rise and set times assume an unobstructed sea-level-style horizon.
- •The ground track is sampled every 30 minutes and is a visualization, not an orbital propagator output.
- •Browser local time interpretation applies to the datetime input.
Authoritative Reference Standards
Troubleshooting & Geographic Edge Cases
Why is the Moon not visible when altitude is positive?
Cloud, haze, buildings, mountains, trees, twilight brightness, and low contrast near the horizon can hide it. The calculation models astronomical position, not local visibility conditions.
Why was geolocation denied?
The browser requires explicit location permission and often requires HTTPS. Enter coordinates manually if permission is unavailable.
Why does the ground track jump at the map edge?
Longitude wraps at the international date line. The tool splits the line there to avoid drawing a false path across the entire map.
Frequently Asked Questions
The purple sublunar marker identifies the latitude and longitude where the Moon is at the zenith for the selected instant.