\begin{table}%t1
%\centering
\par
\caption{Offsets between \object{S2} and the dynamical center \object{Sgr~A*}, computed with the \object{S2} orbit parameters of \citet{eisenhauer03}. Errors are computed by simulating several \object{S2} orbits with gaussian distributions of the orbit parameters (cf.~\citealt{clenet04b}).    \label{table:offset}     }
%\centering
\par
\begin{tabular}{c c c c c c}        
\hline\hline                 
Date & Apr. 24 & Apr. 25 & Jun. 13 & Aug. 10 & Sep. 20 \\    
\hline                        
$\Delta \alpha$ (mas) & 31~$\pm$~5 &  31~$\pm$~5 & 30~$\pm$~5 & 29~$\pm$~5 & 28~$\pm$~5 \\      
$\Delta \delta$ (mas) & 111~$\pm$~9 & 111~$\pm$~9 & 115~$\pm$~8 & 120~$\pm$~5 & 123~$\pm$~4 \\
\hline                                   
\end{tabular}
\end{table}