of $^{56}$Ni and cooled by line emission. The resulting line profiles map rather directly the distribution of the heating material and can be used to derive several properties including $^{56}$Ni mass, mass of the emitting elements, and morphology of the explosion [@Mazzali05].

In order to derive accurate models, we need our spectra to be as spectrophotometrically well calibrated as possible. While the relative fluxes of our data are accurate because of our flux-calibration routines (see §\[s:obs\]), the absolute fluxes may be off due to imperfect observing conditions. To address this, we obtained publicly available photometric data on [SN 2001ig]{} from ESO and the Space Telescope – European Coordinating Facility (ST-ECF) Science Archive Facility[^2]. The observations were single 60 s Bessell [@Bessell90] $R$-band images taken with the FORS1 spectrograph mounted on the ESO 8.2-m Very Large Telescope Melipal and Antu [@Appenzeller98].

We calibrated both images, observed on 2002 Oct. 12 and 2002 Dec. 8, to the United States Naval Observatory B1.0 (USNOB) Catalog with three comparison stars and measured magnitudes for [SN 2001ig]{} of 17.99$\pm$0.08 and 19.13$\pm$0.14, respectively. In addition to our stated statistical uncertainty, we adopt a systematic uncertainty of [$\sim\!\!$ ]{}0.25 mag based on comparisons of USNOB magnitudes to 