\begin{table}%t1 
\caption{\label{table:1}Overview of the molecular line transitions observed with APEX.}   
%\centering
\par
\begin{tabular}{c c c c} 
\hline\hline\noalign{\smallskip}             
   Species   & Transition  & $\nu$ (MHz)  & HPBW (\arcsec) \\    
\hline
   $^{12}$CO &   3--2        & 345~796.00  &  18        \\
             &   4--3        & 461~040.78  &  14        \\
             &   7--6        & 806~651.81  &   8        \\
\hline
   $^{13}$CO & 3$_3$--2$_2$  & 330~587.94  &  19        \\
\hline
    SiS      &  16--15       & 290~380.31  &  21        \\
             &  17--16       & 308~515.63  &  20        \\
             &  19--18       & 344~778.78  &  18        \\
             &  20--19       & 362~906.34  &  18        \\
\hline
\hline
$^{28}$SiO      &  7--6         & 303~926.81  &  20        \\
             &  8--7         & 347~330.59  &  18        \\
\hline
 $^{29}$SiO  & 7--6         & 300~120.47   & 20         \\
             & 8--7         & 342~980.84   & 18         \\
\hline
 $^{30}$SiO  & 7--6         & 296~575.75   & 21         \\
             & 8--7         & 338~930.03   & 18         \\
\hline
    SO       & 7$_7$--6$_6$  & 301~286.13  &  20        \\
             & 8$_8$--7$_7$  & 344~310.63  &  18        \\
\hline
    SO$_2$   & 3$_{3~ 1}$--2$_{2~ 0}$   & 313~279.72  & 20   \\
             & 17$_{1~17}$--16$_{0 ~16}$ & 313~660.84  & 20   \\
             & 4$_{3~1}$--3$_{2~2}$     & 332~505.25  & 19   \\
             & 13$_{2~12}$--12 $_{1~11}$  & 345~338.53  & 18   \\
             & 5$_{3~3}$--4$_{2~2}$     & 351~257.22  & 18   \\
             & 14$_{4~10}$--14$_{3~11}$ & 351~873.88  & 18   \\
\hline
   CS        & 6--5         & 293~912.25   & 21         \\
             & 7--6         & 342~883.00   & 18         \\
\hline
    HCN      & 4--3         & 354~505.47   & 18         \\
\hline
   CN        & $N=3$--2, $J=5/2$--3/2  & 340~031.56  & 18   \\
             & $N=3$--2, $J=7/2$--5/2  & 340~247.78  & 18   \\
\hline \hline
\multicolumn{4}{c}{\emph{masers}}\\
\hline
  H$_2$O     & 10$_{2~9}$--9$_{3~6}$    & 321~225.63  &  19  \\
             & 5$_{1~5}$--4$_{2~2}$     & 325~152.91  &  19  \\
\hline
 $^{28}$SiO  & $v=1$, 7--6    & 301~814.30   &  20  \\
             & $v=1$, 8--7    & 344~916.35   &  18  \\
             & $v=3$, 7--6    & 297~595.41   &  20  \\
\hline
 $^{29}$SiO  & $v=1$, 7--6    & 298~047.33   &  20  \\
\hline
 $^{30}$SiO  & $v=1$, 8--7    & 336~602.44   &  19  \\
\hline                                    
\end{tabular}
\tablefoot{The third column lists the transition frequency, the last column the beam size (HPBW). For CN, only the strongest hyperfine component is given.} 
\end{table}