\begin{table}%t1
\caption{\label{tab1}VLA 18-cm OH observational summary.} 
%\centering
\par
\begin{tabular}{ccccc}
\hline\hline\noalign{\smallskip}
Frequency & HPBW               &  PA    & Resolution & $t_{\rm integration}$\\
(MHz)     & (\as$\times$\as)   & (\degr)& (\kms)     & (min)\\
\noalign{\smallskip}\hline
\noalign{\smallskip}
1612      &  $4.0 \times  2.7$ &  55.3  & 9.1        & 144\\
1665      &  $3.9 \times  2.9$ &  64.7  & 8.8        & 169\\
1667      &  $4.0 \times  2.8$ &  61.1  & 8.8        & 173\\
1720      &  $3.7 \times  2.7$ &  57.1  & 8.5        & 148\\
\hline
\end{tabular}
\end{table}