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Old November 7th 18, 10:04 AM posted to sci.astro.amateur
Gerald Kelleher
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Default Geostationary satellites

A satellite in a geostationary orbit is basically an extension of the Lat/Long system into space as a sat hanging over a particular longitude on the surface is much like any object at sea level or on top of a mountain, for although rotational speeds at different in terms of height, they remain rotating with the Earth.

The Earth has two distinct surface rotations so the satellites experience a drift if not corrected although engineers nor much anyone else recognises the Polar day/night cycle and its surface rotational cause as a function of the orbital motion of the Earth -

"There are two other, less serious, problems with geostationary satellites. First, the exact position of a geostationary satellite, relative to the surface, varies slightly over the course of each 24-hour period because of gravitational interaction among the satellite, the earth, the sun, the moon, and the non-terrestrial planets."

https://searchmobilecomputing.techta...nary-satellite

It is proper to speak of an orbital pole or a point on the Earth's surface where the maximum surface rotation arising from an orbital surface rotation reaches zero . A rough guide for maximum rotational speed of the surface is the broken line in this graphic -

http://afewbitsmore.com/img/2015_ecliptic.png

The rotational speed parallel to the orbital plane at the maximum equatorial circumference is, on average, about 68.17 miles per day so the satellites are picking this up just as observers on the ground picked up variations in the natural noon cycle.