Left panel: V luminosity function of the blue HeB stars. The bin width is 0.15 mag. The errors shown are derived by the artificial star tests. Plotted above the histogram is the age in Myr for the blue HeB stars as given by the MESA models. Right panel: SFR in M_⊙ Myr⁻¹ kpc⁻² for NGC 4535 within our field over the last 60 Myr, based on the blue HeB stars. The blue HeB luminosity function has been normalized to account for the IMF and the changing lifetime in this phase with mass. We used the Salpeter IMF slope and the MESA evolutionary tracks for Z = 0.0014.