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We examined the Wilson-Bappu effect, a relationship between the absolutemagnitude of the star, $M_V$, and the logarithm of the Ca {\sc ii} emissionwidth, $W_0$, over the largest $M_V$ range to date, +13 to -5, coveringM-dwarfs to type Ia supergiants. We used an extensive literature, the latestHipparcos reduction, data from two globular clusters, and new observations fromApache Point Observatory to compile a sample that allowed us to study theeffect of [Fe/H] on the Wilson-Bappu relationship. Our results includereporting the deviations from linearity and demonstrating that the Wilson-Bappurelationship is insensitive to metallicity.

The [Fe/H] Dependence on the Ca {\sc ii}-$M_V$ Relationship