through to the various $uvby\beta$ indices we use the calibrations of [@crawfordmandwewala1976]:

$$\begin{aligned}
E(m_1) &= -0.33 E(b-y) \\
E(c_1) &= 0.20 E(b-y) \\
E(u-b) &= 1.54 E(b-y).\end{aligned}$$

From these relations, given the intrinsic color index $(b-y)_0$, the reddening free parameters $m_0, c_0, (u-b)_0,$ and $a_0$ can be computed.

In § \[subsec:tefflogguncertainties\] we quantify the effects of extinction and extinction uncertainty on the final atmospheric parameter estimation, $T_\mathrm{eff}, \log g$.

Utility of the Photometric System {#subsec:uvbyutility}
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From the four basic Strömgren indices – $b-y$ color, $\beta$, $c_1$, and $m_1$ – accurate determinations of the stellar atmospheric parameters $T_\text{eff}, \log g$, and $[M/H]$ are possible for B, A, and F stars. Necessary are either empirical [e.g. @crawford1979; @lester1986; @olsen1988; @smalley1993; @smalley1995; @clem2004], or theoretical [e.g. @balona1984; @moon1985; @napiwotzki1993; @balona1994; @lejeune1999; @castelli2006; @castelli2004; @onehag2009] calibrations. Uncertainties of 0.10 dex in $\log g$ and 260 K in $T_\text{eff}$ are claimed as achievable and we reassess these uncertainties ourselves § \[subsec:tefflogguncertainties\].

Determination of Atmospheric Parameters $T_\mathrm{eff}, \log g$ {#sec:atmosphericparameters}
================================================================

Procedure {#subsec:atmosphericparameters}
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![image](f3.pdf){width="99.00000%"} ![image](f4.pdf){width="99.00000%"}

Once equipped with $uvby\beta$ colors and indices and understanding the effects of extinction, arriving at the fundamental parameters $T_\text{eff}$ and $\log g$ for program stars, proceeds by interpolation among 