\begin{table}%T1
\caption{\label{obslog}\emph{XMM-Newton} RGS1/2 observations of  RX~J0720.4$-$3125.}
\small
%\centering
\par
\begin{tabular}{cccc}
\hline\hline 
Obs. ID & Obs. Date Start & Exposure & Effective exposure \\
        &   JD-2~400~000 &  ks   &    ks           \\
\hline
0124100101 & 51~678.1503935 &  65.87   & 15.45 \\
0132520301 & 51~870.2714931 &  30.91   & 30.24 \\
0156960201 & 52~585.2443171 &  30.24   & 29.60 \\
0156960401 & 52~587.3090509 &  32.04   & 31.03 \\
0158360201 & 52~762.0499190 &  81.63   & 73.43 \\
0161960201 & 52~940.2405093 &  44.92   & 44.67 \\
0164560501 & 53~147.9273380 &  51.95   & 44.36 \\
0300520201 & 53~488.8618634 &  53.31   & 50.69 \\
0300520301 & 53~636.4891551 &  53.01   & 51.38 \\
0311590101 & 53~687.4349306 &  39.71   & 38.91 \\
0400140301 & 53~877.6977662 &  21.91   & 21.57 \\
0400140401 & 54~044.9718634 &  21.91   & 21.69 \\
0502710201 & 54~226.2093171 &  21.91   & 21.57 \\
0502710301 & 54~421.7184259 &  24.92   & 24.59 \\
\hline                                   
\end{tabular}
\end{table}