\begin{table}%t3 \caption {\label{tab:mag_limits} Saturation limits and limiting magnitudes at 3$\sigma$ level (see Sect.~\ref{catalog}). In the fourth column, the corresponding limiting mass for cluster members (i.e. assuming an age between~30 and 50~Myr and a distance of 150~pc) derived from the evolutionary models by \citet{Bar98} and \citet{Cha00} is reported; in the last column the magnitude corresponding to the Hydrogen burning limit ($\sim$0.07~$M_{\odot}$) for IC~2391 members is also given for comparison.} %\centerline {\begin{tabular}{ccccc} \hline\hline Filter & Mag Sat. & Mag 3$\sigma$ & Mass 3$\sigma$ & PHB$^\dagger$\\ & & & ($M_\odot$) & \\ \hline $V$ & 10.5 & 24.7 & 0.03 & 20.0 \\ $R_{\rm C}$ & 10.0 & 23.7 & 0.03 & 18.5 \\ $I_{\rm C}$ & 9.5 & 23.0 & 0.02 & 17.0 \\ \hline \end{tabular}} \par \smallskip $^\dagger$ {PHB = Photometric Hydrogen Burning limit for IC~2391 members.} \end{table}