\begin{table}%t1
\caption{The permanent dipole moments of the molecules and the rest 
frequencies of the observed transitions.
\label{table:lineparameters}}
%\centerline
 {\begin{tabular}{lcccc}
\hline\hline
Molecule &  $\mu~^a$ & \multicolumn{2}{c}{Transition} & $\nu~^a$    \\
         & (Debye)&         &                      & (MHz)    \\\hline
\hcn     & 2.98   &         & $F=1{-}1$              & 88630.416\\
         &        & $J=1{-}0$ & $F=2{-}1$              & 88631.847\\
         &        &         & $F=0{-}1$              & 88633.936\\
\hthicn  & 2.98   &         & $F=1{-}1$              & 86338.767\\
         &        & $J=1{-}0$ & $F=2{-}1$              & 86340.184\\
         &        &         & $F=0{-}1$              & 86342.274\\
\hnc$~^b$ & 3.05  &         & $F=1{-}1$              & 90663.656\\
          &       & $J=1{-}0$ & $F=2{-}1$              & 90663.574\\
          &       &         & $F=0{-}1$              & 90663.450\\
\hnthic$~^b$ &2.70&         & $F=1{-}1$              & 87090.942\\
             &    & $J=1{-}0$ & $F=2{-}1$              & 87090.859 \\
             &    &         & $F=0{-}1$              & 87090.735 \\
\hfifnc      &2.70& $J=1{-}0$ &                      & 88865.715\\
\ammo        &1.48 & $(J,K)=$   & $(1,1)$ & 23694.495 \\
             &     & $(J,K)=$   & $(2,2)$ & 23722.633 \\ \hline
\end{tabular}}
\par
\smallskip
\qquad$^a$ \verb1http://spec.jpl.nasa.gov1. \\
\smallskip
\qquad$^b$ Frequencies from Frerking et~al. (\cite{frerking1979}).
\par
\end{table}