\begin{table}%t1
\caption{Position of Achernar B relative to Achernar A.}
\label{naco_astrom}
\small%\centerline
 {
\begin{tabular}{lrccccc}
\hline \hline
&&&&&& \\[-8pt]
Epoch & $\lambda$ ($\mu$m) & $\Delta \alpha$$^{{a}}$ & $\sigma(\alpha)$ & $\Delta \delta$$^{{a}}$ & $\sigma(\delta)$ & $R_p$$^{{b}}$ \\
&&&&&& \\[-8pt]
\hline
2006.760$^{{c}}$ & 11.25 & --184.0 & 7.5 & 211.0 & 7.5 & 12.3 \\
2007.488 & 2.17 & --95.9 & 6.6 & 178.6 & 6.6 & 8.9 \\
2007.824 & 2.17 & --46.9 & 6.6 & 165.8 & 6.6 & 7.6 \\
2007.975 & 2.17 & --35.3 & 6.6 & 148.2 & 6.6 & 6.7 \\
\hline
\end{tabular}}
\medskip
$^{{a}}$ Differential coordinates and uncertainties in milliarcseconds (mas). \\
$^{{b}}$ Projected A--B separation in AU.\\
$^{{c}}$ From Kervella \& Domiciano de Souza (\cite{kervella07}).
\end{table}