\begin{table}%t1
\caption{Log of the observations.}\label{obs_tab}
%\centering
\par
\begin{tabular}{llccc}
      \hline
      \hline
Date, UT               & Grism & $T_{\exp}$ & Airmass & Seeing\\
                       &       & (sec)     &         & (arcsec)\\
     \hline
 & \multicolumn{2}{c}{4U~0614+091}\\
2003 Nov. 04, 07:22:08 & 600B & 1735 & 1.22 & 0.73 \\
2003 Nov. 04, 07:54:57 & 600B & 1735 & 1.20 & 0.78 \\
2003 Nov. 03, 07:40:17 & 600R & 1735 & 1.21 & 1.00 \\
2003 Dec. 15, 06:25:42 & 600R & 1735 & 1.28 & 0.52 \\
2003 Dec. 15, 07:00:31 & 600R & 1735 & 1.37 & 0.57 \\
 & \multicolumn{2}{c}{4U~1626-67}\\
2004 Mar. 23, 08:22:00 & 600B & 1735 & 1.37 & 0.76 \\
2004 Mar. 23, 09:01:42 & 600B & 1735 & 1.36 & 0.77 \\
2004 Mar. 21, 08:48:53 & 600R & 1735 & 1.36 & 1.58 \\
2004 Mar. 22, 08:19:40 & 600R & 1735 & 1.37 & 0.87 \\
2004 Mar. 22, 09:00:00 & 600R & 1735 & 1.36 & 0.71 \\
2004 Mar. 23, 07:41:51 & 600R & 1735 & 1.40 & 0.57 \\
 & \multicolumn{2}{c}{EG~274}\\
2004 Mar. 23, 09:48:17 & 600B & 50   & 1.05  & 0.67 \\
2004 Mar. 23, 09:53:25 & 600R & 40   & 1.05  & 0.67 \\
\hline
\end{tabular}
\end{table}