\begin{table}%t1
\caption{Str\"{o}mgren photometry of the optical counterpart to
4U~2206+54. The last column 
indicates the telescope used. a stands for the 1.5-m Spanish telescope
at Calar Alto. b represents the 1.23-m German telescope. c is the
Skinakas 1.3-m telescope.}
\label{tab:opticalphotom}
%\centering
\par
\begin{tabular}{lccccccc}
\hline\hline
Date & MJD &$V$ &$(b-y)$ & $m_{1}$ &$c_{1}$ &$\beta$& $T$\\
\hline
1988, Jan. 7 &47168.290   & 9.909~$\pm$~0.013  &0.257~$\pm$~0.005  &$-$0.083~$\pm$~0.007  & 0.011~$\pm$~0.007    &2.543~$\pm$~0.040 & a \\
1989, Jan. 4 &74531.305   & 9.845~$\pm$~0.015  &0.257~$\pm$~0.007  &$-$0.042~$\pm$~0.010  & $-$0.117~$\pm$~0.017 &2.543~$\pm$~0.007 & a \\
1991, Nov. 16 &48577.401  & 9.960~$\pm$~0.034  &0.268~$\pm$~0.005  &$-$0.040~$\pm$~0.012  & $-$0.041~$\pm$~0.033 & --            & b \\
1991, Dec. 19 &48610.297  & 9.969~$\pm$~0.038  &0.271~$\pm$~0.021  &$-$0.322~$\pm$~0.006  & $-$0.010~$\pm$~0.018 &2.489~$\pm$~0.024 & b \\
1994, Jun. 21 &49524.500  & 9.835~$\pm$~0.019  &0.258~$\pm$~0.013  &$-$0.032~$\pm$~0.021  & 0.053~$\pm$~0.030    &2.617~$\pm$~0.020 & b \\ 
1996, May 26 &50229.642  & 9.845~$\pm$~0.012  &0.267~$\pm$~0.007  &$-$0.052~$\pm$~0.012  & $-$0.074~$\pm$~0.013 &2.553~$\pm$~0.006 & a \\
1999, Aug. 16 & 51407.500 & 9.883~$\pm$~0.031  &0.255~$\pm$~0.044  &$-$0.226~$\pm$~0.074  & 0.298~$\pm$~0.094    & $-$            & c \\
\hline
\end{tabular}
\end{table}