\begin{table}%t12 
%\centering
\par
\caption{Ratio of the \pronaos to
\isophot average brightnesses on extended sources. The average value
is weighted using 1/$\sigma^2$.}  
\label{tab_isophot_extended}
\begin{tabular}{lc} 
\hline 
\hline
Source&PRONAOS/ISOPHOT\\
\hline       
$\rho$-Ophiuchi &1.25~$\pm$~0.13\\
M~42-1 &0.98~$\pm$~0.07\\ 
M~42-2 &$1.01\pm0.07$\\
\hline 
Average&$1.04\pm0.07$\\
\hline 
\end{tabular}  
\end{table}