The IAU 2000 Resolutions for Astrometry, Celestial Mechanics, and Metrology in the Relativistic Framework: Explanatory Supplement

Research output: Contribution to journalArticle


We discuss the IAU resolutions B1.3, B1.4, B1.5, and B1.9 that wereadopted during the 24th General Assembly in Manchester, 2000, andprovides details on and explanations for these resolutions. It isexplained why they present significant progress over the correspondingIAU 1991 resolutions and why they are necessary in the light of presentaccuracies in astrometry, celestial mechanics, and metrology. In fact,most of these resolutions are consistent with astronomical models andsoftware already in use. The metric tensors and gravitational potentialsof both the Barycentric Celestial Reference System and the GeocentricCelestial Reference System are defined and discussed. The necessity andrelevance of the two celestial reference systems are explained. Thetransformations of coordinates and gravitational potentials arediscussed. Potential coefficients parameterizing the post-Newtoniangravitational potentials are expounded. Simplified versions of the timetransformations suitable for modern clock accuracies are elucidated.Various approximations used in the resolutions are explicated andjustified. Some models (e.g., for higher spin moments) that serve thepurpose of estimating orders of magnitude have actually never beenpublished before.


  • M. Soffel
  • S. A. Klioner
  • G. Petit
  • P. Wolf
  • S. M. Kopeikin
  • P. Bretagnon
  • V. A. Brumberg
  • N. Capitaine
  • T. Damour
  • T. Fukushima
  • B. Guinot
  • T.-Y. Huang
  • Lennart Lindegren
  • C. Ma
  • K. Nordtvedt
  • J. C. Ries
  • P. K. Seidelmann
  • D. Vokrouhlický
  • C. M. Will
  • C. Xu
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology


  • Astrometry, Celestial Mechanics, Time, Reference Systems
Original languageEnglish
Pages (from-to)2687-2706
JournalAstrophysical Journal
Issue number6
Publication statusPublished - 2003
Publication categoryResearch

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