Inertial space

As an astronomical- physical inertial reference system is referred to, which can be regarded as being at rest or moves uniformly and no rotational movement.

The current best realization of such a reference system is the average orientation of space, as represented by the positions of about 500 distant quasars. She agrees to about 0.02 " with an ideal inertial match.

Until about 1980, the inertial space was realized by the star positions of about 1600 fundamental stars - see FK5 and FK6. Based on the definition of the position in space are accurately measured natural movements of a large number of stars, the average movement is assumed to be zero.

Although the inertial space has a purely physical quality, it can also be approximated in a geometric way by using only distant celestial bodies shall be with probably slower proper motion for its realization. In addition to this task, the high-precision astrometry, it is also feasible in the technical field, such as the gyro-stabilization of missiles.