\begin{table}%T1
\caption{\label{tabObs}Observed H$_2$$^{16}$O, H$_2^{18}$O, and CO~transitions.}
\scriptsize
%\centering
\par
\begin{tabular}{r c c r c c}
\hline \hline
Transition & $\nu$ & $E_{\rm u}/k_{\rm B}$ & Transition & $\nu$ & $E_{\rm u}/k_{\rm B}$ \\ 
           & (GHz) & (K) &  & (GHz) & (K) \\ \hline\noalign{\smallskip}
p-H$_2$$^{16}$O~1$_{11}$--0$_{00}$         & 1113.34                    & \phantom{1}53.4  & o-H$_2$$^{18}$O~1$_{10}$--1$_{01}$ & \phantom{1}547.68 & \phantom{1}60.5 \\
p-H$_2$$^{16}$O~2$_{02}$--1$_{11}$        & \phantom{1}987.93 & 100.8                      &  p-H$_2$$^{18}$O~2$_{02}$--1$_{11}$             & \phantom{1}994.68 & 100.7 \\
p-H$_2$$^{16}$O~2$_{11}$--2$_{02}$        & \phantom{1}752.03 & 136.9                      &  C$^{18}$O\ \ \ \ \ \ \ 5--4 & \phantom{1}548.83 & 79.02 \\
o-H$_2$$^{16}$O~3$_{12}$--3$_{03}$        & 1097.37                     & 249.4                     & $^{13}$CO~\  \ \ \ \ 10--9& 1101.35 &     290.79    \\
                                                                              &                                     &                                 & CO~10--9\tablefootmark{a} \ \ \ \ \      10--9 & 1151.99 & 304.2  \\
 \hline
\end{tabular}
\tablefoot{\tablefoottext{a}{Only a preliminary reduction of this observation has been performed, it is discussed only in Sect.~3.2.}}
\vspace*{-2mm}
\end{table}