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IAU C.A3 facilitates advances in astronomy, and other fields in science and engineering, by developing, implementing, and communicating fundamental IAU-endorsed standards for astronomy. Such standards include, but are not limited to:

  • celestial & terrestrial reference systems/frames and the transformations among them;
  • time scales;
  • precession-nutation models;
  • Earth rotation and polar motion, including physical models (e.g., Earth's gravity field, lunar gravity field, Earth interior model, solid Earth-tide modelling);
  • star catalogues;
  • ephemerides of Solar System bodies;
  • coordinate systems of Solar System bodies;
  • special and general relativistic models for time and space.

News ...

2020 April: Commission A3 Website Updates
  • A3 webages transferred to gitlab hosting; content updated
  • NSFA WG website and lists of standards websites now being hosted by Commission A3
  • Masses of Ceres & Vesta added as Developing Standards for discussion
  • NSFA Best Estimates updated for new potential of geoid value

Commission A3 Meetings and Reports

Send comments, questions, suggestions, corrections to: @ President of C.A3 or @ Webmaster

Last modified: 2020 April