How can you tell if a satellite dish is tracking a satellite in a low-Earth orbit or a geosynchronous orbit?

1 Answer
May 30, 2016

Does it move and if it does, does it follow a path that repeats every sidereal day?

Explanation:

The word geosynchronous is made up of three parts:

  • geo- meaning the "Earth".
  • syn- meaning "together".
  • chronous meaning "time"

So a satellite in geosynchronous orbit keeps time with the Earth, orbiting the Earth once for every one rotation of the Earth. From the perspective of a ground observer, it traces out a path that repeats every sidereal day.

So a satellite dish tracking such a satellite would follow a path that repeats every sidereal day. Or...

Note that the most commonly used kind of geosynchronous orbit is also geostationary. If the plane of the orbit of the satellite is equatorial (and the orbit is in the same direction as the rotation of the Earth, not backwards), then the satellite will seem stationary from the perspective of a ground observer.

A satellite dish tracking a geostationary satellite does not need to move at all.

A satellite in low Earth orbit will not be geostationary and there is no reason for it to be geosynchronous either. So a dish tracking it will move and not follow a path that repeats once overy sidereal day.