\begin{table}%t1
      \caption{\label{filters}Imaging log.}
%\centerline
{
\begin{tabular}{llll}
            \hline
\hline
  \hnii\        & \sii\         & \oiii\ & Date    \\
\hline
2400$^{a}$(1)$^{b}$   &4800 (2)&--   & 09-08-2002    \\
2400(1)                      &2400 (1)&--    & 10-08-2002    \\
--                           & --     &7200(3)& 11-08-2002    \\
2400(1)                      &2400 (1)&--    & 12-08-2002    \\
4800(2) 	             &4800 (2)&--    & 13-08-2002    \\
\hline
4800(2)$^{*}$ 	             &--      &--    & 14-06-2004    \\
 4800(2)$^{*}$ 	             &--      &--    & 15-06-2004    \\
 --          	             &2400 (1)&--    & 20-06-2004    \\
 2400(1) 	             &--      &--    & 21-06-2004    \\
 2400(1) 	             &2400 (1)&2400 (1)& 22-06-2004    \\
  6560$^{c}$(75$^{d}$)  & 6708 (20) & 5005 (28 )  \\
 \hline
\end{tabular}}
\smallskip
${^a}$ Total exposure time in s. \\ 
${^b}$ Number of individual frames. \\ 
${^c}$ Central wavelength in \AA.   \\ 
${^d}$ Full width at half maximum in \AA.  \\ 
$^{*}$ Each of the two frames covers different fields.
   \end{table}