Azimuth
- Clockwise from true north
- —
Satellite dish
Observer latitude and longitude, typed or set by a click on the map, and the longitude of a geostationary satellite. The orbit radius is 42,164 km from the Earth’s centre, on the same sphere as the GRS80 mean radius, …. Azimuth and elevation follow. An elevation below the horizon is said plainly. There is no terrain and no weather.
The left side is the elevation in the vertical plane. The horizontal line is the geometric horizon. A ray below that line is below the horizon. The dial is the azimuth, clockwise from north. The drawing is the angles, not the 42,164 km orbit to scale.
- Line of sight, when it is up
- Line of sight, when it is below the horizon
- Azimuth
Elevation
- Above the geometric horizon
- —
Range
- Observer to satellite
- —
The map did not load. The latitude and longitude you type still work.
Hold Ctrl and scroll to zoom the map. The scroll wheel alone moves the page.
What this page shows
The observer is on the mean sphere. The satellite is on the equator, 42,164 km from the Earth’s centre. Azimuth is clockwise from true north. Elevation is the angle of the straight line of sight above the local horizontal. A negative elevation is below the horizon, and the page says so. The satellite is then not visible on this sphere. The map marker is the observer. A click sets that place. The satellite longitude is not a click.
The preset is Stockholm, 59.3293° N, 18.0686° E, the city position used on the other pages, and a satellite longitude of 5° E. That longitude is an example slot. It is not a claim about which satellite is stationed there today.
Assumptions
- The Earth is the GRS80 mean sphere from the shared geometry module. Geodetic and geocentric latitude are the same on that sphere.
- The orbit radius is 42,164 km, a round figure for a geostationary radius. A closer Kepler radius depends on the gravity constant and the length of the sidereal day. This page does not fit one satellite’s measured orbit.
- The satellite longitude is the longitude of the point on the equator under it. The satellite has no inclination and no drift.
- No refraction, no terrain, and no weather. A positive elevation can still be blocked by a hill. The page does not know the hill.
- When the satellite is overhead, one azimuth is not defined, and the card says so.
- Hold Ctrl and scroll to zoom the map. The scroll wheel alone moves the page. A click sets the observer. It does not set the satellite longitude. The map requests tiles from OpenStreetMap. The coordinates are used only in this browser.
Sources
- Moritz, H. (1980). Geodetic Reference System 1980. The sphere is the mean radius from the shared geometry module.
- 42,164 km is the stated round figure for the orbit radius. It is not taken from a live satellite catalogue.
- Stockholm, 59.3293° N, 18.0686° E, the city position already used on this site. The slot at 5° E is an example, not an assignment of a craft.
- Map tiles © OpenStreetMap contributors.