\begin{table}%t3
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\par
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\par
\caption{Lower  limit  magnitude  of detectability of a putative lensing galaxy 
according to its  position (Cols. 2, 3 and 4). Column~5 displays the
minimal redshift for an $\mathcal{L}^*$ galaxy of this magnitude.\label{limit_mag} }
\begin{tabular}{lcccl}
\hline\hline
Position  & $R$& $J$ & $Ks$&   \\
\hline
(a) 0.8\arcsec~ East to A  & 25.5 & 24.0    &22.5 &$z>1.9$\\
(b) 0.4\arcsec~ West to B&  26.5 &24.5    &24.5 &$z>3.2$\\
(c) 7.0\arcsec~ South-West to A  &27.0 &24.5 & 24.5          &$z>4.5$ \\
\hline
\end{tabular}
\end{table}