\begin{table}%T2
%\centering
\small
\caption{Mean relation between the effective temperature and $(B-V)_0$,
$(b-y)_0$, $(B2-V1)_0$, as well as $(g_1-y)_0$ for A-type to mid F-type, 
luminosity class~V to~III~objects. Only spectral types according to the
Yerkes system (Keenan \cite{Keenan85}) are listed.}
\label{standard}
\begin{tabular}{crcccc}
\hline
\hline
Spec. & $T_{\rm eff}$ & $(B-V)_0$ & $(b-y)_0$ & $(B2-V1)_0$ & $(g_1-y)_0$ \\
\hline
A0 & 10~000 & $-$0.025 & $-$0.015 & $-$0.160 & $-$0.010 \\
A2 &  8750 & +0.067   & +0.031   & $-$0.093 & +0.025   \\
A3 &  8300 & +0.112   & +0.055   & $-$0.060 & +0.042   \\
A5 &  7900 & +0.161   & +0.082   & $-$0.024 & +0.062   \\
A7 &  7500 & +0.221   & +0.120   & +0.022   & +0.087   \\
F0 &  7050 & +0.304   & +0.185   & +0.087   & +0.125   \\
F2 &  6750 & +0.368   & +0.238   & +0.141   & +0.155   \\
F3 &  6650 & +0.390   & +0.254   & +0.159   & +0.165   \\
F5 &  6450 & +0.433   & +0.284   & +0.196   & +0.184   \\
\hline
\end{tabular}
\end{table}