\begin{table}%t1
%\centering
\par
\caption{The astrometrical calibration of all observing runs for which data are shown in this
paper. The pixelscale PS and the detector position angle   PA  with their uncertainties are
listed. The detector is tilted by  PA  from north to west.}\label{calibration}
\begin{tabular}{cccc}
\hline\hline
Instrument & Epoch & PS [$''$] & PA [$^{\circ}$]\\
\hline
UFTI & 11/02 & $0.09098\pm0.00043$ &  ~~~$0.770\pm0.087$\\
UFTI & 10/03 & $0.09104\pm0.00030$ &   ~~~$0.711\pm0.083$\\
\hline
SofI$_{\rm small}$ & 12/02 & $0.14366\pm0.00016$  & $90.069\pm0.041$\\
SofI$_{\rm small}$ & 06/03 & $0.14365\pm0.00013$  & $90.069\pm0.032$\\
SofI$_{\rm small}$ & 07/04 & $0.14356\pm0.00011$  & $90.047\pm0.024$\\
\hline
SofI$_{\rm large}$ & 07/04 & $0.28796\pm0.00032$  & $90.176\pm0.045$\\
\hline 
\end{tabular}
\end{table}