\begin{table}%T1
%\centering
\par
\caption{Log of the XMM-Newton RGS observations of Mkn~421 taken in 2002 and 2003
that were used during this analysis.
A further observation of Mkn~421 0537\_0136540701 was also performed during the
cooling of RGS1 which we have not used.
$^a$ Total amount of Good Time Intervals.
$^b$ The reprocessing of these data failed; we exclude them from 
further analysis.}
\label{tab1}
\begin{tabular}{cccccc}
\hline\hline
\multicolumn{6}{c}{\bf XMM-Newton RGS}\\
\hline
Revolution & Obs. id. & \multicolumn{2}{c}{Start time} & Total exposure$^a$ & Net exposure  \\
           &          &  Day & Hour   &  ($10^4$ s)    & ($10^4$ s)   \\
\hline
 0532      & 0136540301 & 04/11/2002 & 00:44:59&  2.3        &  2.1 \\
%\hline
 0532      & 0136540401 & 04/11/2002 & 07:41:43 & 2.3        &  2.1 \\
%\hline
 0546      & 0136541001 & 01/12/2002 & 22:59:25 & 7.1        &  5.8 \\
%\hline
 0637      & 0158970101 & 01/06/2003 & 12:48:50 & 4.3        &  3.0 \\ 
%\hline
 0720      & 0150498701 & 14/11/2003 & 16:14:04 & 5.7        &  4.7 \\
\hline
\end{tabular}
\end{table}