\begin{table}%t2
\par
\caption {\label{tab:c2h21}Line parameters$^{a}$ observed in \cch(2$-$1).} % title of Table 
%\centerline
 {
\begin{tabular}{c c c c} % centered columns (4 columns) 
\hline\hline % inserts double horizontal lines 
$\alpha,\delta$ offsets & $V_{\rm LSR}$ & $\Delta V$ & $\tau_{\rm total}^{\;b}$ \\ % table heading
$[$\arcsec,\arcsec] & [km s$^{-1}$] & [km s$^{-1}$] &\\  
\hline % inserts single horizontal line 
\multicolumn{4}{c}{L1498}\\
$0,0$ & 7.84(0.01) & 0.23(0.01) & 8.6(1.8)\\
$60,-40$ & 7.76(0.01) & 0.25(0.01) & 9.7(1.9)\\
\hline
\multicolumn{4}{c}{CB246}\\
$0,0$ & $-$0.84(0.01) & 0.35(0.02) & 1.5(1.2)\\
$15,-30$& $-$0.73(0.01) & 0.30(0.01) & 5.4(1.0)\\
$-60,15$ & $-$0.88(0.01) & 0.30(0.01) & 5.5(1.2)\\
\hline 
\end{tabular}}
\par
\smallskip
$^a$ Numbers in parentheses represent the errors from the fit.
$^b$ Sum of the peak optical depth of the seven hyperfine components.
\end{table}