  We detect stars from the Hipparcos and Tycho Catalogues in the field of view
of observations with the ROSAT HRI of three globular clusters. We use the
positions of these stars to reduce the systematic error in the positions of
X-ray sources in the clusters to ~2'' for omega Cen and NGC6752, and 1'' for
NGC6397. We detect three X-ray sources in the core of omega Cen, and four in
the core of NGC6752; the data for the center of NGC6397 may be fitted with five
or six sources. Outside the cores, but within the half-mass radius of the
clusters, we detect two sources in omega Cen, one in NGC6397 and two in
NGC6752; these may or may not be cluster members. A ROSAT HRI observation of
Liller 1 does not detect a low-luminosity source, at a limit below a detection
with ASCA. We discuss the nature of the low-luminosity X-ray sources in
globular clusters in the light of these new results.
