************************************************************************
IERS Message No. 173                                  September 06, 2010
************************************************************************


Information on the updates to the IERS Conventions


The IERS Conventions Center informs of the following updates:

Two chapters of the IERS Conventions have been updated on 3 September
2010:

Chapter 2 "Conventional celestial reference system and frame" see
http://tai.bipm.org/iers/convupdt/convupdt_c2.html.

The chapter has been significantly rewritten, with F. Arias,
S. Bouquillon, A. Fey, G. Francou and N. Zacharias as main contributors.
It describes ICRF2, the second realization of the ICRF recommended as
the fundamental realization of the ICRS by Resolution B3 of the IAU
(2009).

Chapter 4 "Terrestrial reference systems and frames" 
see http://tai.bipm.org/iers/convupdt/convupdt_c4.html.
A presentation of ITRF2008, the current reference realization of the
ITRS, is now included (from Z. Altamimi). The subroutine GCONV2 is
proposed for coordinate transformation.

Chapter 5 "Transformation between the International Terrestrial
Reference System and Geocentric Celestial Reference System" has been
updated on 5 September 2010:
see http://tai.bipm.org/iers/convupdt/convupdt_c5.html.
Change the sign of the term in t**4 for X in equation 16 (noted by
C. Hohenkerk).

Gerard Petit and Brian Luzum
IERS Conventions Center


************************************************************************
IERS Messages are edited and distributed by the IERS Central Bureau.
To submit texts for distribution and to subscribe or unsubscribe,
please write to <central_bureau@iers.org>.
Archives: http://www.iers.org/Messages/
************************************************************************