\begin{table}%t1
%\centering
\par
\caption{\label{tab-obs}Details of the \xmm\ EPIC PN observations on \msh.}
\begin{tabular}{lrr}
\hline\hline
\noalign{\smallskip}
\multicolumn{1}{c}{Observation} &
\multicolumn{2}{c}{Exposures (ks)} \\
\multicolumn{1}{c}{ID} &
\multicolumn{1}{c}{performed\tablefootmark{1}}& 
\multicolumn{1}{c}{net\tablefootmark{2}} \\
\hline
0207050201 & 23.135 & 5.9\\
0302730201 & 16.130 & 3.6\\
0302730301 & 8.235 & 2.0\\
\hline
\end{tabular}
\tablefoot{\tablefoottext{1}{Exposure time without background screening.}
\tablefoottext{2}{Net exposure time after background screening.}}
\end{table}