\begin{table}%t2
   \caption{Relative position of the components of HD 219542.}
     \label{t:astrometry}
%\centerline
{ 
       \begin{tabular}{ccccccc}
         \hline
         \hline
         Epoch      &  $\rho$ & Error & $\theta$ & Error & $\theta_{2000.0}$ & Ref. \\
         \hline
1830.51  & 4.56  &       & 26.7  &      & 26.5  & 1 \\
1890.64  & 4.75  &       & 30.6  &      & 30.5  & 1 \\
1909.05  & 4.96  &       & 29.9  &      & 29.8  & 1 \\
1917.32  & 4.96  &       & 30.3  &      & 30.2  & 1 \\
1924.40  & 4.97  &       & 29.2  &      & 29.1  & 1 \\
1953.545 & 5.103 & 0.013 & 30.94 & 0.16 & 30.89 & 2 \\
1960.699 & 5.11  & 0.02  & 30.8  & 0.2  & 30.8  & 3 \\
1976.784 & 5.02  &       & 31.3  &      & 31.3  & 4 \\
1991.25  & 5.279 & 0.004 & 31.53 &      & 31.52 & 5 \\
1991.797 & 5.280 & 0.002 & 31.47 & 0.02 & 31.46 & 6 \\
1994.747 & 5.29  & 0.20  & 32.05 & 0.78 & 32.05 & 7  \\   
        \hline
      \end{tabular}}
\medskip
References:  
             1 Aitken  (\cite{aitken});
             2 van Albada-van Dien (\cite{vanalbada78});
             3~van~Albada-van~Dien (\cite{vanalbada83});
             4 Holden (\cite{holden});
             5 Hipparcos (ESA \cite{hipparcos})
             6 Cuypers \& Seggewiss (\cite{cuypers99});
             7 Popovic \& Pavlovic (\cite{popovic}).
\end{table}