\begin{table}%Ta1
  \caption{\label{tab:photosol}Coefficients of photometric calibration 
  defined by Eq.~(\ref{eq:photofit}) for the photometric nights
  used to calibrate the observations of \cldzero, CL0159+0030, and CL0809+2811.}
  \small%\centering
\par
 \begin{tabular}{ccccccc}
 \hline\hline\noalign{\smallskip}
   Filter & Obs.\ Date & $Z_{{f}}$\tablefootmark{\dagger} & $\beta_{{f}}$ & Colour index & $\gamma_{{f}}$ & $n_{{\rm par}}$\tablefootmark{\ddagger} \\\noalign{\smallskip}
    \hline\noalign{\smallskip}
   $g'$ & 2005-10-30 & $27.27\pm0.02$ & $0.106\pm0.007$ & $g'-r'$ & $-0.14\pm0.02$ & 3 \\
        & 2005-10-31 & $27.15\pm0.02$ & $0.124\pm0.008$ & $g'-r'$ & $-0.08\pm0.01$ & 3 \\
        & 2005-11-01 & $27.35\pm0.02$ & $0.115\pm0.005$ & $g'-r'$ & $-0.21\pm0.02$ & 3 \\ 
        \noalign{\smallskip}
   $i'$ & 2005-10-30 & $26.49\pm0.02$ & $0.127\pm0.004$ & $r'-i'$ & $-0.11\pm0.02$ & 3 \\
        & 2005-10-31 & $26.47\pm0.01$ & $0.122\pm0.002$ & $r'-i'$ & $-0.09\pm0.01$ & 3 \\
        & 2005-11-01 & $27.41\pm0.01$ & $0.119\pm0.002$ & $r'-i'$ & $-0.03\pm0.01$ & 3 \\ 
        \noalign{\smallskip}
   $r'$ & 2005-10-30 & $26.95\pm0.02$ & $0.046\pm0.002$ & $g'-i'$ & $-0.10\pm0.02$ & 3 \\
        & 2005-10-31 & $26.90\pm0.01$ & $0.043\pm0.003$ & $g'-i'$ & $-0.05\pm0.01$ & 3 \\
        & 2005-11-01 & $26.96\pm0.01$ & $0.048\pm0.004$ & $g'-i'$ & $(-0.10)$\tablefootmark{{\S}} & 2 \\
        & 2005-11-08 & $26.81\pm0.01$ & $0.046\pm0.003$ & $g'-i'$ & $(-0.10)$\tablefootmark{{\S}} & 2 \\ \hline
 \end{tabular}
\tablefoot{\tablefoottext{{\dagger}}{Normalised to an exposure time of $1\mbox{s}$ and 
    an airmass $a=0$.}\\
  \tablefoottext{{\ddagger}}{Number of parameters used in the fit.}\\
  \tablefoottext{{\S}}{Fixed to default value.}}
\end{table}