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Earth Orientation Parameters 1899.7-1992.0 In The Hipparcos Reference Frame

Published online by Cambridge University Press:  14 August 2015

J. Vondrák
Affiliation:
1Astronomical Institute, Boční II, 141 31 Prague 4, Czech Republic
C. Ron
Affiliation:
1Astronomical Institute, Boční II, 141 31 Prague 4, Czech Republic
I. Pešek
Affiliation:
2Czech Technical University, Thákurova 7, 166 29 Prague 6, Czech Republic
A. Čepek
Affiliation:
2Czech Technical University, Thákurova 7, 166 29 Prague 6, Czech Republic

Extract

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The optical astrometry observations of latitude/universal time variations made with 48 instruments at 31 observatories are used to determine the Earth orientation parameters (EOP) since the beginning of the century. The Hipparcos Catalogue is used to bring more than four million individual observations, made in the interval 1899.7-1992.0, into the International Celestial Reference System. The Earth orientation parameters (polar motion, celestial pole offsets and, since 1956.0, also universal time UT1) are determined at 5-day intervals, with average uncertainties ranging from 8 mas (in the eighties) to about 40 mas (in the forties). Making use of very long series of ground-based observations, the solution also leads to the improvement of proper motions of about ten per cent of the observed Hipparcos stars, with precision of ±0.2 — 0.5 mas/yr. In addition, 474 auxiliary parameters, describing the rheological properties of the Earth and seasonal deviations of the observations at contributing observatories, are found. The new solution provides the EOP series suitable for further analyses, e.g., for studying long-periodic polar motion, length-of-day changes or precession/nutation.

Type
II. Joint Discussions
Copyright
Copyright © Kluwer 1998