IAU Commission 19: Terms of Reference


Commission 19 of the International Astronomical Union (IAU) is a part of IAU Division I. The Commission is created to support and coordinate scientific investigations on the Earth rotation and related reference frames.


  1. Encourage and develop cooperation and collaboration in observation and theoretical studies of Earth orientation (the motions of the pole in the terrestrial and celestial reference systems and the rotation about the pole).
  2. Serve the astronomical community by linking it to the official organizations providing the International Terrestrial and Celestial Reference Systems/Frames (ITRS/ITRF and ICRS/ICRF) and Earth orientation parameters (EOP): International Association of Geodesy (IAG), International Earth Rotation and Reference System Service (IERS), International VLBI Service for Geodesy and Astrometry (IVS), International GNSS Service (IGS), International Laser Ranging Service (ILRS), International DORIS Service (IDS).
  3. Develop methods for improving the accuracy and understanding of Earth orientation and related reference systems/frames.
  4. Ensure agreement and continuity of the reference frames used for Earth orientation with other astronomical reference frames and their densification.
  5. Provide means of comparing observational and analysis methods and results to ensure accuracy of data and models.


The organization of the Commission is governed by the IAU statues, by-laws and working rules which are available from the IAU website: http://www.iau.org/administration/statutes_rules/

The Commission consists of its members and is chaired by the President. To coordinate its activity, the Commission forms the Organizing Committee (OC).

Each IAU member who is interested in the participation in the Commission activity may be a member of the Commission. No election procedure for a membership is established; only recommendation from the Commission 19 OC is needed.

The IAU General Assembly elects the President and Vice-President of the Commission for a 3-year term coordinated with the IAU General Assemblies. This term is not renewable. Candidates are proposed by the Commission from its members through voting and are elected by the IAU General Assembly. The Vice President is normally proposed to the General Assembly as the President for the next term.

The Organizing Committee includes ex-officio members (the present Commission President, the present Commission Vice-President, the past Commission President, and representatives from the IAG, the IERS, the IVS) and up to 5 additional members at large. The representatives of the IAG, IERS and IVS are supposed to represent also the other Services that are not in the OC: the IGS, IDS and ILRS. At-large members are nominated by the OC, selected by the Commission members through the voting and elected by the IAU General Assembly. As a rule, an OC member cannot serve more than two successive terms unless (s)he is elected as the President or Vice-President.

The Commission may propose Working Groups to fulfil specific tasks at the Commission level as well as at the Division level.

Representatives of the Services providing Earth orientation parameters (IERS, IVS, IGS, ILRS, IDS) should be invited to the Commission 19 Business Meetings and other events and report there.

International Year of Astronomy