\begin{table}%t1 \caption{\label{conti}Measured rms (at a frequency resolution of 1.1~MHz) and assumed continuum values for the different transitions (in $T_{\rm mb}$ scale). } \small %\centering \par \begin{tabular}{c c c c c} \hline\hline \noalign{\smallskip} HIFI band & Transition & Frequency & rms & Continuum \\ & ($N _J{-}N\arcmin_J\arcmin$) & (GHz) & (mK) & (mK)\\ \hline 1a & ND (0$_1$--1$_2$) & 522.1 & 12 & 203 $\pm$ 22\\ 1a & ND (0$_1$--1$_1$) & 546.2 & 15 & 230 $\pm$ 24\\ 3b & NH (0$_1$--1$_0$) & 946.5 & 58 & 832 $\pm$ 80\\ 4a & NH (0$_1$--1$_2$) & 974.5 & 49 & 892 $\pm$ 143\\ 4a & NH (0$_1$--1$_1$) & 1000.0 & 50 & 942 $\pm$ 146\\ \hline \end{tabular} \vspace*{-2mm} \end{table}