\begin{table}%t1
%\centering
\par
\caption{\label{t:astrometry}Reference star astrometry from GSC-II. Both right ascension,
  $\alpha$, and declination, $\delta$, are given in degrees. The
  rightmost column quotes the names of the stars as they appear in GSC-II.}
\begin{tabular}{cccl}
 \hline \hline\noalign{\smallskip}
Star & $\alpha$ & $\delta$  & GSC-II id \\ \noalign{\smallskip}\hline\noalign{\smallskip}
F & 150.41117868 & 55.90692350  & N212232175   \\
G & 150.40026155 & 55.89505952  & N212232178   \\
H & 150.36551899 & 55.89125437  & N212232182   \\
E & 150.37040443 & 55.87405306  & N212232187   \\
D & 150.36712201 & 55.86871933  & N212232190   \\
X & 150.41965483 & 55.87058001  & N212232189   \\
R & 150.40374136 & 55.86788639  & N21223213199 \\ \hline 
\end{tabular}
\end{table}