\begin{table}%t6
\caption{\label{15ghz}Maxima and minima in flux density, position angle and core separation at epochs~1998 and~2000 at~15~GHz.}
%\centering
\par
\begin{tabular}{lrrrrrr}
\hline\hline\noalign{\smallskip}
\multicolumn{1}{c}{Time} & \multicolumn{3}{c}{{1998}} & \multicolumn{3}{c}{{2000}}\\
Comp. ID & Flux & PA & Core sep. & Flux & PA & Core sep.\\
\hline
Core & min & & & max & & \\
C0 & max & max & min& & & \\
C1 & & & & max & max & max \\
Ca & max & min & max & min & max& min\\
\hline
\end{tabular}
\end{table}