\begin{table}%T1
\caption{\mbox{XMM-Newton} observations of \sn\ and data selection.}
\small%\centerline
{
\begin{tabular}{llcclrrr}
\hline\hline\noalign{\smallskip}
\multicolumn{1}{l}{Instrument} &
\multicolumn{1}{c}{Read-out} &
\multicolumn{1}{c}{Filter} &
\multicolumn{1}{c}{Sat. Revol.} &
\multicolumn{1}{c}{Date} &
\multicolumn{1}{c}{Time (UT)} &
\multicolumn{1}{c}{Net Exp$^1$.} &
\multicolumn{1}{c}{Counts$^2$} \\
\multicolumn{1}{c}{} &
\multicolumn{1}{c}{Mode} &
\multicolumn{1}{c}{} &
\multicolumn{1}{c}{} &
\multicolumn{1}{c}{} &
\multicolumn{1}{c}{} &
\multicolumn{1}{c}{[s]} &
\multicolumn{1}{c}{} \\
 \hline 
\mbox{EPIC-pn}      & FF, 73 ms & Medium &  21 & 2000 Jan. 19/20 & 16:19--04:28 &  23~250 &  2194 \\
\mbox{EPIC-pn}      & FF, 73 ms & Medium &  22 & 2000 Jan. 21    & 15:38--19:34 &   5789 &   518 \\
\mbox{EPIC-pn}      & FF, 73 ms & Thin   &  22 & 2000 Jan. 21/22 & 20:32--12:02 &  30~990 &  3060 \\
 \hline 
\mbox{EPIC-pn}      & FF, 73 ms & Medium & 244 & 2001 Apr. 8/9   & 20:35--07:14 &  24~534 &  3952 \\
 \hline 
\mbox{EPIC-pn}      & SW, 6 ms  & Medium & 626 & 2003 May 10/11  & 16:41--23:37 &  55~855 & 25~609 \\
EPIC-MOS1    & FF, 2.6 s & Medium &     &                 & 16:35--23:37 & 101~520 & 16~020 \\
EPIC-MOS2    & FF, 2.6 s & Medium &     &                 & 16:35--23:37 & 101~510 & 16~018 \\
RGS1         & Spectro   & --     &     &                 & 11:42--23:38 & 112~160 &  2509 \\
RGS2         & Spectro   & --     &     &                 & 10:47--23:38 & 111~670 &  3358 \\
 \hline
\end{tabular}}
\smallskip
$^1$ Net exposures for the observations from revolutions 21/22 were derived from a comparison
of the spectrum of N~157~B with that obtained from the ROSAT PSPC due to missing timing
information in the early data \citep{2001AetA...365L.208H}. 
$^2$ Net counts as used for the spectral analysis in the following energy bands: 
0.2$-$9.0~keV for the EPIC instruments 
(except for \mbox{EPIC-pn} during revolutions 21/22 when we adopted 0.3$-$9.0~keV due to the 
higher low-energy threshold used at the beginning of the performance verification phase); 
0.3$-$2.0~keV for RGS.
\label{xray-obs}
\end{table}