Observed HST spectrum of a standard supernova of type Ia at early phase – SN 1992A approximately 5 days after maximum, representing an epoch of about 25 days after explosion (Kirshner et al. 1993). Since Kirshner et al. have found no reason to correct for extinction, we have taken their data as-is. Furthermore, we are only interested in the shape of the spectrum, not the (distance-dependent) absolute flux, therefore we treat the scaling as a free parameter in the following comparison plots.