\begin{table}%T2
%\centering
\small
\caption{Details of FORS2 spectroscopic mask mode observation 
           (see Fig.~\ref{exposure_map2}).\label{tab:fors2}} 
\begin{tabular}{cccc}\hline \hline
 Mask & Observation  & Filter & Seeing \\ 
      & (each 1800~s) &        & (in arcsec)\\ 
\hline
   mask1  &    3 &  none   & 0.63\\ 
   mask2  &    4 &  none   & 1.36\\ 
   mask3  &    3 &  none   & 1.05\\ 
   mask4  &    3 &  none   & 0.78\\ 
   mask5  &    3 &  none   & 0.93\\ 
   mask6  &    3 &  GC 375  & 0.75\\ 
   mask7  &    3 &  none   & 0.80\\ 
   mask8  &    3 &  none   & 0.81\\ 
   mask9  &    2 &  none   & 0.66\\ 
  mask10  &    3 &  none   & 0.76\\ 
  mask11  &    1 &  none   & 0.96\\ 
  mask12  &    2 &  none   & 0.64\\\hline 
\end{tabular}
\end{table}