\begin{table}%t3
\caption{Integration time required to detect the HDO lines with a peak signal over noise of 5 (see text). Note that only one receiver was assumed, so in principle those times can be lowered by a factor $\sqrt{2}$ by using a double polarization setup.
\label{int_time}}
%\begin{center}
{\begin{tabular}{llll}
\noalign{\smallskip}
\hline\hline
\noalign{\smallskip}
Transition & IRAM 30~m & JCMT & HSO/HIFI \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
\multicolumn{4}{l}{IRAS 16293 (30 $L_{\odot}$)}\\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
80 GHz & 5.6 h & & \\
225 GHz & 15 min & & \\
241 GHz & 30 min & & \\
464 GHz & & 29 min & \\
490 GHz & & 21 min & 7 min \\
509 GHz &  & 34 h$^*$ & 104 min \\
893 GHz & & & 16 min \\
995 GHz & & & 5 min \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
\multicolumn{4}{l}{L1448~mm (5 $L_{\odot}$)}  \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
80 GHz & 3500 h & & \\
225 GHz & 110 h & & \\
241 GHz & 227 h & & \\
464 GHz & & 185 h   & \\
490 GHz & &132  h   & 73 h \\
509 GHz & & 1562 h $^*$  & 471 h  \\
893 GHz & & & 59 h  \\
995 GHz & & & 16 h  \\
\hline 
\end{tabular}}
\parbox{7cm}{
$^*$ The sensibility drops on the edge of the band.}
%\end{center}
\par
\end{table}