\begin{table}%t4 \caption{\label{tab:wfi}Summary of the \WFI\ optical observations performed by the ESO/MPG 2.2~m telescope.} %\centering \small \begin{tabular}{l|crcc} \hline \hline Date & Filter & Time (s) & Airmass & Seeing \\ \hline 10 Mar. 2005 & $R$ & 2888.75 & 1.09 & 0.99 \\ & $I$ & 1999.73 & 1.15 & 1.09 \\ 01 May 2005 & $V$ & 2559.09 & 1.11 & 0.52 \\ 02 May 2005 & $I$ & 269.42 & 1.10 & 0.69 \\ 25 Feb. 2006 & $I$ & 1999.59 & 1.09 & 0.86 \\ 25 Apr. 2006 & $B$ & 1999.59 & 1.09 & 0.68 \\ & $U$ & 2499.59 & 1.11 & 0.61 \\ \hline \end{tabular} \end{table}