\begin{table}%t2
\caption{Absolute surface brightnesses (in Jy/beam) of
           \object{Mars}, \object{Uranus}, \object{W3~OH},
	   \object{K3-50A} and \object{NGC~7027} adopted
           for the computation of the \mbox{Kelvin-to-Janksy}
	   conversion factors {of the 30~m telescope}
	   at 86~GHz and 229~GHz.\label{primcal}}
\par
\small
%\centerline
 {\begin{tabular} {lcccccc}
\hline\hline\noalign{\smallskip}
         &  \multicolumn{6}{c}{UT days of Nov. 2003}\\
\hline\noalign{\smallskip}
 Source  & 11 & 12 & 13 & 14 & 15 & 16 \\
\hline\noalign{\smallskip}
\multicolumn{7}{c}{$86$~GHz}\\
\hline\noalign{\smallskip}
\object{Mars}$^{{a}}$      & 149.75 & 146.88 & 144.08 & 141.33 & 138.65 & 136.02 \\
\object{Uranus}$^{{a}}$    &   7.06 &	7.05 &   7.04 &   7.03 &   7.01 &   7.01 \\
\object{W3~OH}$^{{b}}$    & \multicolumn{6}{c}{3.94} \\
\object{K3-50A}$^{{b}}$   & \multicolumn{6}{c}{6.29} \\
\object{NGC~7027}$^{{b}}$ & \multicolumn{6}{c}{4.71} \\
\hline\noalign{\smallskip}
\multicolumn{7}{c}{$229$~GHz}\\
\hline\noalign{\smallskip}
\object{Mars}$^{{a}}$      & 691.16 & 683.33 & 675.51 & 666.71 & 659.92 & 652.17 \\
\object{Uranus}$^{{a}}$    &  32.88 &  32.83 &  32.77 &  32.72 &  32.67 &  32.61 \\
\object{W3~OH}$^{{b}}$    & \multicolumn{6}{c}{6.48} \\
\object{K3-50A}$^{{b}}$   & \multicolumn{6}{c}{6.98} \\
\object{NGC~7027}$^{{b}}$ & \multicolumn{6}{c}{3.68} \\
\hline
\end{tabular}}
\par
\smallskip
$^{{a}}$ Computed from the expressions given in
           Kramer~(\cite{Kra97}), and references therein,
	   {which take into account the angular size of
	   the planets. The values given for \object{Uranus} were
	   computed from an empirical model which used
	   \object{Mars} as primary calibrator
	   (Griffin \& Orton~\cite{Gri93}).}
\par
$^{{b}}$ Obtained from averages of measurements performed
           during several years -- before 1996 -- at the
	   IRAM 30~m telescope. These measurements were
	   themselves calibrated through observations of planets.
	   {The sizes of these calibrators at 1.2~mm are given
	   in Lisenfeld et~al.~(\cite{Lis00}).}
\end{table}