\begin{table}%t6
%\centering
\par
\caption{\label{tab:xray}Log of X-ray observations.}
\begin{tabular}{ccc}
\hline\hline
Instrument & Start date (UTC)& Exp (s)\\
\hline
XRT & 2006-10-27 05:55:53 & 3000\\
XRT & 2006-10-30 06:15:21 & 3800\\
XRT & 2006-10-31 06:21:26 & 3400\\
XRT & 2008-02-10 16:22:48 & 6700\\
XRT & 2008-02-12 16:24:38 & 5200\\
RXTE & 2006-11-01 00:06:40 & 7200\\
XMM & 2005-03-20 16:05:56 & 80~000\\
BAT & 2006--2008 & 2-years\\
\hline
\end{tabular}
\end{table}