\begin{table}%t1 %\centering \par \caption{\label{t:parameters}Parameters of the observed lines of the $N=1{-}0$ transition.} \begin{tabular}{cccccc} \hline\hline \noalign{\smallskip} $J^{\prime} \leftarrow J^{\prime\prime}$ & $ F^{\prime} \leftarrow F^{\prime\prime}$ & Frequency & $g_{\rm l}$ & $g_{\rm u}$ & A \\ & & (MHz) & & & ($10^{-2}~{\rm s}^{-1}$) \\ \hline 0 1 & 1/2 1/2 & 909045.2 & 2 & 2 & 0.524 \\ 0 1 & 1/2 3/2 & 909158.8 & 4 & 2 & 1.048 \\ \hline \end{tabular} \tablefoot{The frequencies were taken from \citet{bekooy+1985} and the Einstein~$A$ coefficients from the Cologne Database for Molecular Spectroscopy \citep[CDMS,][]{mueller+2005}. Note that the Einstein~$A$ coefficients given by \citet{dealmeida1990} are too high by a factor~1.5.}\vspace*{1.5mm} \end{table}