Both solar time and sidereal time make use of the regularity of Earth's rotation about its polar axis, solar time following the Sun while sidereal time roughly follows the stars.
32.
By these procedure, the polar axis of the reference ellipsoid becomes parallel to the Earth rotation axis, and therefore the vertical deflection of the fundamental point is " zero ".
33.
The IAU recommends the " mean Earth / polar axis " system, in which the prime meridian is the average direction ( from the Moon's center ) of the Earth's center.
34.
In the case of oxide compounds intended for transparent conducting films or surface acoustic wave ( SAW ) devices, for instance, the polar axis should be aligned along the substrate normal.
35.
Instead, they have a mechanism which rotates about a polar axis at a constant speed of 15 degrees per hour, keeping pace with the average speed of the Earth's rotation relative to the Sun.
36.
Dr . Fischer disagreed with the established figure for the oblateness of the earth ( the fraction by which the polar axis is foreshortened by the equatorial radius ), which had remained unchallenged since 1924.
37.
In 1988 Georges D'Autume proposed a more sophisticated design which used conical bearings surfaces all around to raise the height of the " virtual polar axis " to make the mount better balanced for heavier loads.
38.
But if the moment of inertia around one of the two axes close to the equator becomes nearly equal to that around the polar axis, then the constraint on the orientation of the object ( the Earth ) is relaxed.
39.
:: : Steve's point is valid, but mostly nullified by the fact that the Earth's shape is very close to an ellipsoid of revolution whose polar axis is the same one that our latitude and longitude coordinates are based on.
40.
Non-zero coefficients " C n m ", " S n m " correspond to a lack of rotational symmetry around the polar axis for the mass distribution of Earth, i . e . to a " tri-axiality " of Earth.
