Photometric Metallicities in Bootes I
  We present new Stromgren and Washington data sets for the Bootes I dwarf
galaxy, and combine them with the available SDSS photometry. The goal of this
project is to refine a ground-based, practical, accurate method to determine
age and metallicity for individual stars in Bootes I that can be selected in an
unbiased imaging survey, without having to take spectra. We produce photometric
metallicities from Stromgren and Washington photometry, for stellar systems
with a range of $-1.0>[Fe/H]>-3.5$. To avoid the decrease in sensitivity of the
Stromgren metallicity index on the lower red-giant branch, we replace the
Stromgren v-filter with the broader Washington C-filter; we find that $CT_1by$
is the most successful filter combination, for individual stars with
$[Fe/H]<-2.0$, to maintain ~0.2 dex $[Fe/H]$-resolution over the whole
red-giant branch. We demonstrate that we can break the isochrones'
age-metallicity degeneracy with these filters, using stars with log g=2.5-3.0,
which have less than a 2% change in their $(C-T_1)$-colour due to age, over a
range of 11-14 Gyr.
