Differences between UCAC3 and PPMXL in positions and proper
motions, on
an all-sky one-degree grid. At each gridpoint we give the
differences X(PPMXL)- X(UCAC3) averaged over all stars in
a sqrt(2)/2-degrees environment around the gridpoint given. The
corrections given here should bring UCAC3 based astrometry to the ICRS.