Contribution of the main astronomical observatory of Ukrainian academy of sciences to the link of the Hipparcos and extragalactic reference frames

Absolute proper motions of stars with respect to galaxies obtained within the KSZ programme were used in the determination of spin parameters of the Hipparcos catalogue system relative to the inertial reference frame. Solutions using bright, faint, blue, and red stars as well as the whole magnitude range of stars were found. The faint KSZ stars' solution (omega(x) = -0.27 +/- 0.80mas/yr, omega(y) = +0..15 +/- 0.60mas/yr, omega(z) = -1.07 +/- 0.80mas/yr) is considered as the most reliable and is recommended for the correction of the Hipparcos catalogue system.