Questions involving reference frames, time scales, and how they are determined. Not for general Astronomy 101 questions.
IAU Division A is responsible for fundamental astronomy.
The scientific community of Division A:
- provides definitions and models that describe reference systems and frames used in astronomy to determine positions and motions of celestial objects in space and time;
- investigates dynamical behavior of celestial bodies including both high-accuracy descriptions for shorter periods of time and evolution over extended periods of time;
- obtains physical information on celestial objects and investigates physical laws using the methods of astrometry and celestial mechanics;
- offers services that provide data and ephemerides of solar system bodies, Earth orientation data, time scales, astronomical constants, models including relevant software procedures, etc. for users within the astronomical community as well as within society.