\begin{table}%t2
%\centering
\par
\caption{ROSAT observations.\label{t2}}  
\begin{tabular}{cccc}
\hline
\hline Start date & Start time UT & End date & End time UT \\
\hline 6-10-92 & 02:51:35 & 6-10-92 & 03:14:20 \\ 6-10-92 &
04:15:58 & 6-10-92 & 04:51:54 \\ 6-10-92 & 07:43:53 & 6-10-92 &
08:06:17 \\ 6-10-92 & 10:39:47 & 6-10-92 & 11:19:39 \\ 6-10-92 &
13:56:15 & 6-10-92 & 14:35:02 \\ 7-10-92 & 02:35:57 & 7-10-92 &
03:08:58 \\ 7-10-92 & 04:13:57 & 7-10-92 & 04:46:13 \\ 7-10-92 &
07:22:43 & 7-10-92 & 08:00:13 \\ 7-10-92 & 10:34:22 & 7-10-92 &
11:13:28 \\ 7-10-92 & 13:49:36 & 7-10-92 & 14:29:28 \\ 7-10-92 &
21:43:25 & 7-10-92 & 22:08:39 \\ 8-10-92 & 00:54:43 & 8-10-92 &
01:26:13 \\ 8-10-92 & 05:45:10 & 8-10-92 & 06:17:29 \\ 8-10-92 &
07:17:53 & 8-10-92 & 07:55:00 \\ 8-10-92 & 12:06:56 & 8-10-92 &
12:44:31 \\ 8-10-92 & 21:40:45 & 8-10-92 & 22:03:23 \\ 8-10-92 &
23:14:05 & 8-10-92 & 23:43:23 \\ 9-10-92 & 02:26:25 & 9-10-92 &
02:57:43 \\ 9-10-92 & 05:37:08 & 9-10-92 & 06:12:13 \\ 9-10-92 &
10:25:06 & 9-10-92 & 11:01:43 \\ 9-10-92 & 13:39:14 & 9-10-92 &
14:19:14 \\ 9-10-92 & 21:33:41 & 9-10-92 & 21:58:23 \\ 10-10-92 &
02:20:52 & 10-10-92 & 02:52:28 \\ 10-10-92 & 05:32:48 & 10-10-92 &
06:06:27 \\ 10-10-92 & 10:19:25 & 10-10-92 & 10:55:57 \\ 10-10-92
& 13:36:29 & 10-10-92 & 14:14:42 \\ 10-10-92 & 21:29:12 & 10-10-92
& 21:53:09 \\ \hline
\end{tabular}
\end{table}