\begin{table}%t1
\caption{Summary of observational results.}\label{tab1}
%\centering
\par
%\begin{tabular}{@{}ccc@{~~~}c@{~~~}c@{}}
\begin{tabular}{@{}cc|c@{~~~}cc}
\hline
\hline
Maser&$\nu_{\rm{rest}}$&$R\rm{_{in}}$~~~$R\rm{_{out}}$&~Restoring beam\\
transition & (MHz)  &(mas)&\hspace{\wd2} size (mas) \hspace{\wd2} ~~~~PA (\degr)\\[2pt]
\hline
 $^{28}$SiO~~ $v=1$ $J=$ 1--0 &43122.080 &10.1~~13.1&~ 0.80 $\times$ 0.53~~~ $-$15.6\\
\hspace*{9mm}$v=2$ $J=$ 1--0 &42820.587 &\hspace{\wd1}8.8~~12.3 &~ 0.85 $\times$ 0.35~~~ $-$12.3\\
 $^{29}$SiO~~ $v=0$ $J=$ 1--0 &42879.916 &11.8~~15.3&~ 0.97 $\times$ 0.73~~~~~~ \hspace{\wd1}$-$7.7  \\
$^{28}$SiO~~ $v=1$ $J=$ 2--1 &86243.442 &14.7~~17.0&~ 0.58 $\times$ 0.48~~~~~~ \hspace{\wd2}16.1 \\[2pt]
\hline
\end{tabular}
\end{table}