spectrum of an A0V star generated by [@munari2005] from an ATLAS9 model atmosphere. The $uvby$ filter profiles are those of [@bessell2011], while the H$\beta$ filter profiles are those originally described in [@crawford1966] and the throughput curves are taken from [@castelli2006].[]{data-label="fig:filters"}](f2.pdf){width="45.00000%"}

Historical use of Strömgren photometry methods indeed has been for the purpose of determining stellar parameters for early-type stars. Recent applications include work by @nieva2013 [@dallemese2012; @onehag2009; @allende1999]. An advantage over more traditional color-magnitude diagram techniques [@nielsen2013; @derosa2014] is that distance knowledge is not required, so the distance-age degeneracy is removed. Also, metallicity effects are relatively minor (as addressed in an Appendix) and rotation effects are well-modelled and can be corrected for (§ \[subsec:vsinicorrection\]).

Description of the Photometric System {#subsec:uvbydescription}
-------------------------------------

The $uvby\beta$ photometric system is comprised of four intermediate-band filters ($uvby$) first advanced by [@stromgren1966] plus the H$\beta$ narrow and wide filters developed by [@crawford1958]; see Figure \[fig:filters\]. Together, the two filter sets form a well-calibrated system that was specifically designed for studying earlier-type BAF stars, for which the hydrogen line strengths and continuum slopes in the Balmer region rapidly change with temperature and gravity.

From the fluxes contained in the six passbands, five $uvby\beta$ indices are defined. The 