Illustration of our fitting procedure for optical spectra with blackbody+host model. The example spectrum was taken with the Baade telescope on MJD 59195. The top panel shows the data and model, and the bottom panel shows the residuals. The fitting model consists of the Planck function (green) and a template for the emission from the host galaxy (black). The best-fit model (red) is defined by log(T_bb/[K]) = 4.10 and results in a bolometric luminosity log(L_bb/[erg s⁻¹]) = 44.3.