distances of our RR Lyrae sample.

For non-variable stars, we first calibrate fiducial points in the $M_V$ vs $(B-V)_o$ relation, using published data from various Galactic globular clusters and the Hyades and Pleiades open clusters to cover large ranges of colors and metal abundances. The globular clusters we use include M92 ($\feh=-2.24$), M15 ($-2.15$), M3 ($-1.66$), M13 ($-1.65$), NGC 6752 ($-1.54$), NGC 362 ($-1.27$), and 47 Tuc ($-0.71$) (Sandage 1970; Buonanno, Corsi, & Fusi Pecci 1989; Durrell & Harris 1993; Penny & Dickens 1986; Harris 1982; Hesser et al. 1987), where metal abundances and extinctions are taken from the compilation of Chaboyer, Demarque, & Sarajedini (1996). The absolute magnitude of the horizontal branch in each cluster is scaled according to Eqn. (1). For the Hyades cluster ($\feh=+0.12$), we adopt the work of Perryman et al. (1998), which utilized the [*Hipparcos*]{} parallaxes to determine the distances to the cluster stars. Using their Figure 21, we read off the fiducial $M_V$ vs $(B-V)_o$ relation for the stars which are not classified as double or multiple in the [*Hipparcos*]{} Catalogue. For the Pleiades cluster ($\feh=+0.11$, essentially identical to the Hyades abundance), we adopt the $M_V$ vs $(B-V)_o$ relation published by Mermilliod (1981).

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