\begin{table}%t4
\caption{The length of the jet at different epochs and in both H$_{\rm \alpha}$ and [SII] filters computed as the distance between the extremes of contours on knots F$_{2}$ (or ``F-complex'' when there is a single contour for both F$_{2}$ and F~knots) and knot~D.}\label{tab:jet-tot}
\small %\centerline
{ \begin{tabular}{lccccccc}
\hline \hline\noalign{\smallskip}
Filter & Year & $\Delta t^{*}$ & Length & Rate of change & Rate of change@150~pc & & $v$ error \\
& & days  & arcsec & arcsec/yr & AU/yr  & km~s$^{-1}$ & km~s$^{-1}$ \\
\hline
H$_{\rm \alpha}$  & 1996 & 0   	& 9.53   & --     & --  & -- & --\\
H$_{\rm \alpha}$  & 1998 & 771  & 9.74   & 0.0994 & 15  & 71 & 34\\
H$_{\rm \alpha}$  & 2005 & 2504 & 10.27  & 0.0773 & 12  & 55 & 10\\
 % \hline
${\rm [SII]}$     & 1996 & 0    & 9.76   & --     & --  & -- & --\\
${\rm [SII]}$     & 1998 & 771  & 10.02  & 0.1231 & 18  & 88 & 34\\
${\rm [SII]}$     & 2005 & 2505 & 10.19  & 0.0248 & 4   & 18 & 10\\
\hline
\end{tabular}}
 \medskip
 $^*$ Number of days between successive epochs. 
   \end{table}