\begin{table}%T2
\caption{\label{astrometry_table}\label{tab2}Astrometry of \obj.
All positions are given relative to the quasar Image A along with their
1-$\sigma$ error bars. The measurements have been
transformed to match the coordinate system of NICMOS (Leh\'ar et~al. \cite{Leh2000}), by using 8 stars common to the AO and NICMOS
fields of view.}
%\centering
\par
\begin{tabular}{lcc}
\hline\hline 
Object    &      $X $                &  $Y$   \\
          & (arcsec)               & (arcsec) \\
\hline
Quasar A  &  0.0                 & 0.0  \\
Quasar B  & $+0.649\pm 0.001 $ & $-0.724\pm 0.001$\\
Star P    & $+0.333\pm 0.002 $ & $-0.504\pm 0.002$\\
Lens G    & $+0.498\pm 0.004 $ & $-0.456\pm 0.004$\\
\hline 
\end{tabular}
\end{table}