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Earth Rotation in the Hipparcos Reference Frame
Vondrák, J.; Ron, C.; Pešek, I.
New determination of the Earth orientation parameters (EOP), based on optical astrometry observations since the beginning of the century, is now under preparation by the Working group established by Commission 19 of the IAU. The Hipparcos catalog is to define the celestial reference frame in which the new series of EOP are to be described, The nov…
Astrometry in the Future
Seidelmann, P. K.
The introduction of the extragalactic reference frame and the availability of the Hipparcos and Tycho catalogs will have major impacts on changing the accuracy levels of astrometry in the future. There is a need for accurate densification of the reference frames down to at least 20th magnitude, Also accurate space motions and distances …