\begin{table}%t1
%\centering
\par
\caption{Log of observations.\label{log}  }% title of Table
   % is used to refer this table in the text
%\centering
                          % used for centering table
\begin{tabular}{ccccl}        % centered columns (4 columns)
\hline\hline                 % inserts double horizontal lines
Filter & $DIT$ & $NDIT$ & $NEXP$ & Date \\    % table heading
\hline                        % inserts single horizontal line
\noalign{\smallskip}
 $J$ & 13~s & 5 & 16 & 29/30 June 2006 \\   % inserting body of the table
     &      &    &   & 29/30 June 2006 \\
 $H$ & 20~s & 4 & 16 & 27/28 July 2006 \\
 $K_{\rm S}$ & 20~s & 4 & 16 & 22/23 July 2006 \\
       &      &   &    & 24/25 July 2006 \\
 $L'$ & 0.175~s & 180 & 28 & 29/30 June 2006 \\
      &         &     &    & 29/30 June 2006 \\
 2.17 & 65 & 1 & 16 & 22/23 July 2006 \\
            &    &   &    & 22/23 July 2006 \\
 2.12 & 65 & 1 & 16 & 17/18 July 2006 \\
      &    &   &    & 28/29 July 2006 \\
\hline 
\end{tabular}
\end{table}