EDP Sciences
Free access
Volume 413, Number 2, January II 2004
Page(s) 765 - 770
Section The solar system
DOI http://dx.doi.org/10.1051/0004-6361:20031552

A&A 413, 765-770 (2004)
DOI: 10.1051/0004-6361:20031552

Rotation matrix from the mean dynamical equator and equinox at J2000.0 to the ICRS

J. L. Hilton1 and C. Y. Hohenkerk2

1  US Naval Observatory, 3450 Massachusetts Ave. NW, Washington, DC 20392, USA
2  Her Majesty's Nautical Almanac Office, Space Science & Technology Dept., Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK

(Received 11 April 2003 / Accepted 23 September 2003)

Recommendation VII of Resolution A4 of the XXIst General Assembly of the International Astronomical Union (IAU 1992) states, in part, "... that the principal plane of the new conventional celestial reference system be as near as possible to the mean equator at J2000.0 and that the origin in this principal plane be as near as possible to the dynamical equinox of J2000.0, ..." The resulting International Celestial Reference System (ICRS), however, has a small, but significant, offset requiring a rotation matrix. The solutions for the offset between the mean dynamical pole of the Earth at J2000.0 and the pole of the ICRS determined by Lunar Laser Ranging (LLR) and Very Long Baseline Interferometry (VLBI) differ by several $\sigma$. Similarly, two different definitions have traditionally been used for the position of the mean equinox. Which of these poles and equinoxes should be used is application dependent. We have shown how the rotation matrix for the rotation from the mean dynamical equator and equinox at J2000.0 to the ICRS changes depending on the various assumptions made in constructing it.

Key words: ephemerides -- reference systems

Offprint request: J. L. Hilton, jhilton@aa.usno.navy.mil

SIMBAD Objects in preparation

© ESO 2004