\begin{table}%t1 \caption{\label{pho}Results of aperture photometry on the TNG imaging frames.} %\centering \par \begin{tabular}{l c c } \hline\hline \noalign{\smallskip} Date & $R$\tablefootmark{a} & $F_{\rm R}$\tablefootmark{b} \\ & [mag] & [$10^{-15} \rm ~ erg ~ cm^{-2} ~ s^{-1} ~ \AA^{-1}$] \\ \hline 2007 Jul. 10--11 & $14.46 \pm 0.01$ & $3.16 \pm 0.01$ \\ 2007 Sep. 7 & $14.21 \pm 0.02$ & $4.12 \pm 0.09$ \\ 2007 Oct. 10 & $13.79 \pm 0.01$ & $6.31 \pm 0.05$ \\ 2008 Jan. 8 & $14.13 \pm 0.03$ & $4.42 \pm 0.11$ \\ \hline \end{tabular} \tablefoot{\tablefoottext{a}{$R$-band magnitudes obtained from photometry with $8 \arcsec$ aperture radius;} \tablefoottext{b}{flux densities at $6410 ~ \AA$ derived from photometry with $2 \arcsec$ aperture radius, used to normalise the spectra.}} \end{table}