\begin{table}%t1
\caption{Summary of the \sax observations of SGR~1900+14.
\label{obs}}
%\centering
\par
\begin{tabular}{ccccccc}
\hline\hline
Obs. & Date & MJD & LECS exposure & MECS exposure & PDS exposure & Period\\
\hline
A & 1997-05-12 & 50~580 & 19.9 ks & 45.8 ks & 20.1 ks & $5.15719\pm0.00003$ s\\
B & 1998-09-15 & 51~071 & 13.8 ks & 33.3 ks & 15.8 ks & $5.16026\pm0.00002$ s\\
C & 2000-03-30 & 51~633 & 14.4 ks & 40.3 ks & 18.3 ks & $5.16709\pm0.00003$ s\\
D & 2000-04-25 & 51~659 & 17.4 ks & 40.5 ks & 18.8 ks & $5.16765\pm0.00003$ s\\
E & 2001-04-18 & 52~017 & 20.4 ks & 46.4 ks & 16.7 ks & $5.17277\pm0.00001$ s\\
F & 2001-04-29 & 52~028 & 25.7 ks & 57.6 ks & 25.6 ks & $5.17298\pm0.00001$ s\\
G & 2001-11-05 & 52~218 & --      & 1.3 ks  & 0.5 ks  & --\\
H & 2002-03-09 & 52~342 & --      & --      & 47.6 ks & --\\
I & 2002-04-27 & 52~391 & --      & 82.9 ks & --      & $5.18019\pm0.00002$ s\\
\hline
\end{tabular}
\end{table}