  We present color-magnitude diagrams of five Galactic globular clusters and
one Galactic open cluster spanning a wide range of metallicity (-2.1 < [Fe/H] <
+0.3), as observed in the F606W (broad V) and F814W (I) bands with the Advanced
Camera for Surveys (ACS) on the Hubble Space Telescope. These clusters are part
of two large ACS programs measuring the star formation history in the Andromeda
halo, tidal stream, and outer disk. In these programs, the clusters serve as
empirical isochrones and as calibrators for the transformation of theoretical
isochrones to the ACS bandpasses. To make these data more accessible to the
community, for each cluster, we provide a ridge line tracing the stars on the
main sequence, subgiant branch, and red giant branch, plus the locus of stars
on the horizontal branch. In addition, we provide the transformation of the
Victoria-Regina isochrones to the ACS bandpasses.
