Topic summary
International Celestial Reference System
Extracted from the Wikipedia article International Celestial Reference System and its realizations.
The International Celestial Reference System (ICRS) is the current standard celestial reference system adopted by the International Astronomical Union (IAU). Its origin is at the barycenter of the Solar System, with axes that are intended to "show no global rotation with respect to a set of distant extragalactic objects". The coordinates are basically the declination and right ascension based on the mean celestial equator and mean celestial equinox at the J2000 epoch.