\begin{table}%t6
\caption{The angular separations of the core and component d relative to the jet apex.
\label{tab:6} }
%\centerline
 {\begin{tabular}{cccccccc}\hline\hline
 &2001.20 &2001.48 &2001.86&2002.11&2002.14&2002.45&Average\\\hline
$\triangle
r_{\rm mas}$&0.23~$\pm$~0.032&0.21~$\pm$~0.036&0.21~$\pm$~0.028&0.36~$\pm$~0.028&0.37~$\pm$~0.032&0.24~$\pm$~0.036&0.27~$\pm$~0.032\\
$r_{a,\rm proj}^{2.3}$&0.32~$\pm$~0.044&0.29~$\pm$~0.050&0.29~$\pm$~0.038&0.50~$\pm$~0.038&0.51~$\pm$~0.044&0.33~$\pm$~0.050&0.37~$\pm$~0.044\\
$r_{a,\rm proj}^{8.4}$&0.087~$\pm$~0.012&0.079~$\pm$~0.014&0.079~$\pm$~0.010&0.14~$\pm$~0.010&0.14~$\pm$~0.012&0.090~$\pm$~0.014&0.10~$\pm$~0.012\\
$R_{a}$&2.31~$\pm$~0.016&2.36~$\pm$~0.024&2.29~$\pm$~0.022&2.30~$\pm$~0.022&2.30~$\pm$~0.016&2.31~$\pm$~0.024&2.31~$\pm$~0.021\\\hline
\end{tabular}}
\par
\smallskip
Notes:$\triangle r_{\rm mas}$ is defined to be the positional offset of the core relative to the jet apex, and is
equivalent to the observed positional difference of component d at 2.3 and 8.4~GHz, $r_{a,\rm proj}^{2.3}$ and
$r_{a,\rm proj}^{8.4}$ are the estimated separation (from Eq.~(1)) of the core from the jet apex at 2.3~GHz and 8.4~GHz, respectively, and $R_{a}$ (from Eq.~(2)) is the estimated separation of component d from the jet apex,
which is independent of frequency.
\end{table}