  How can we accurately determine the metallicity of faint red giant stars in
nearby galaxies? The equivalent widths of the broad absorption lines from Ca II
at 8498, 8542, and 8662 Angstrom (the calcium triplet) have shown a smooth
relationship to metallicity, [Fe/H], in Galactic globular clusters, i.e., old,
metal-poor stars. The exact relationship depends on the [Fe/H] scale assumed.
The sensitivity of the sum of the equivalent widths, sum{W_{Ca II}}, to [Fe/H]
has been well studied for metal-poor stars, but theory and observations show
that sum{W_{Ca II}} will become less sensitive to [Fe/H] for young or
metal-rich stars, but this needs to be calibrated. Built into the present
calibration of sum{W_{Ca II}} to [Fe/H] is also a dependence on the Galactic
[Ca/Fe] to [Fe/H] relationship, which is a function of the Galaxy's star
formation history and chemical evolution. Our goal is to remove uncertainties
in the [Fe/H] scale used in previous calibrations and remove the dependence on
galactic evolution. We are obtaining high dispersion spectra to
self-consistently calibrate the calcium triplet to give [Ca/H] abundances, and
extend the current calibration to near-solar metallicities and to ages as young
as 2 Gyr.
