The International Celestial System (ICRS) is the current standard celestial system adopted by the International Astronomical Union (IAU). Its origin is in the barycentre of the Solar System, with axes that are intended to be "fixed" with respect to space. The ICRS coordinates are approximately equal in equatorial coordinates: the mean pole at J2000.0 in the ICRS is 17.3 ± 0.2 plus in the 12 h direction and 5.1 ± 0.2 plus in the 18 h direction. The mean J2000.0 equinox is changed from the ICRS straight ascension origin by 78 ± 10 more (direct rotation around the polar axis).
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