this, the $\beta$ index is critical. Because the $\beta$ index switches from being a temperature indicator to a gravity indicator in the temperature range of interest to us (spectral type B0-F5, luminosity class IV/V stars), atmospheric parameter determination proceeds depending on the temperature regime. For the $T_\mathrm{eff}$ and $\log g$ calibrations described below, temperature information existed for all of the calibration stars, though this is not the case for our program stars. In the general case we must rely on photometric classification to assign stars to the late, intermediate, and early groups, and then proceed to determine atmospheric parameters in the relevant $uvby\beta$ planes.

[@ttmoon1985] provides a scheme, present in the `UVBYBETA` IDL routine, for roughly identifying the region of the H-R diagram in which a star resides. However, because our primary sample of field stars are assumed to be unextincted, and because the `UVBYBETA` program relies on user-inputted class values based on unverified spectral types from the literature, we opt for a classification scheme based solely on the $uvby\beta$ photometry.

[@monguio2014], hereafter M14, designed a sophisticated classification scheme, based on the work of [@stromgren1966]. The M14 scheme places stars into early (B0-A0), intermediate (A0-A3), and late (later than A3) 