  Spectroscopic abundance determinations for stars spanning a Hubble time in
age are necessary in order to unambiguously determine the evolutionary
histories of galaxies. Using FORS1 in Multi-Object Spectroscopy mode on ANTU
(UT1) at the ESO-VLT on Paranal we obtained near infrared spectra from which we
measured the equivalent widths of the two strongest Ca II triplet lines to
determine metal abundances for a sample of Red Giant Branch stars, selected
from ESO-NTT optical (I, V-I) photometry of three nearby, Local Group,
galaxies: the Sculptor Dwarf Spheroidal, the Fornax Dwarf Spheroidal and the
Dwarf Irregular NGC 6822. The summed equivalent width of the two strongest
lines in the Ca II triplet absorption line feature, centered at 8500A, can be
readily converted into an [Fe/H] abundance using the previously established
calibrations by Armandroff & Da Costa (1991) and Rutledge, Hesser & Stetson
(1997). We measured metallicities for 37 stars in Sculptor, 32 stars in Fornax,
and 23 stars in NGC 6822, yielding more precise estimates of the metallicity
distribution functions for these galaxies than it is possible to obtain
photometrically. In the case of NGC 6822, this is the first direct measurement
of the abundances of the intermediate-age and old stellar populations. We find
metallicity spreads in each galaxy which are broadly consistent with the
photometric width of the Red Giant Branch, although the abundances of
individual stars do not always appear to correspond to their colour. This is
almost certainly predominantly due to a highly variable star formation rate
with time in these galaxies, which results in a non-uniform,
non-globular-cluster-like, evolution of the Ca/Fe ratio.
