\begin{table}%t1
\caption{Continuum and 3-$\sigma$ noise level in the antenna temperature scale on the CO(1$-$0) and CO(2$-$1) spectral bands.}\label{sigma}
%\centering
\small
  \begin{tabular}{c c c c c}
    \hline \hline
                & \multicolumn{2}{c}{115 GHz} & \multicolumn{2}{c}{230 GHz} \\
    $T_{\rm a}^{*}$ & continuum & 3-$\sigma$      & continuum & 3-$\sigma$      \\ 	     \hline
    \object{Saturn}      & 30.1 K    & 213 mK          & 37.5 K    & 420 mK          \\
    \object{Uranus}      & 1.65 K    &   9 mK          & 2.9 K     &  33 mK          \\
    \hline
  \end{tabular}
\end{table}