\begin{table}%T1
\par
%\centering
\par
\caption{Scale calibration of the $U$ plate for the SMC.}\label{t1}
\begin{tabular}{ccc} \hline\hline
Spectral type & $U_{\rm SMC}$ & Age \\ \hline
O5 & 11.9 & $3\times10^6$\\
B0 & 13.5 & $4\times10^6$\\
B1 & 14.6 & $6\times10^6$\\
B2 & 15.4 & $1\times10^7$\\
B3 & 16.3 & $1.5\times10^7$\\
B4 & 16.7 & $2.8\times10^7$\\
B5 & 17.2 & $4\times10^7$\\
B6 & 17.5 & $1\times10^8$\\
B7 & 17.9 & $1.6\times10^8$\\
B8 & 18.4 & $2\times10^8$\\
B9 & 18.5 & $3\times10^8$\\
A0 & 19.7 & $4\times10^8$\\ \hline
\end{tabular}
\end{table}