Visual wavelength spectrum of the nucleus of NGC 5775 shown in the host-galaxy rest frame (in black), and the resulting single stellar population synthesis computed by STARLIGHT (in red). The continuum-subtracted spectrum is shown in blue, where the most prominent host nebular emission features are labeled. The nebular lines shown within the insets provide flux ratios indicating a metallicity higher than solar of 8.7 ± 0.2 dex on the O3N2 scale at the core of the host. When we adopt the metallicity gradient from Pilyugin et al. (2004) of −0.47 dex , the metallicity at the position of SNhunt120 is estimated to be 8.34 dex. When we assume an uncertainty of 0.1 dex for the gradient, the uncertainty on the metallicity at the SN position would be 0.22 dex.