\begin{table}%t2
%\centering
\par
\caption{RSS, SWS and NL parameters.  No.: serial number of the observation. 
PA$_{\rm RSS}$: measured position angle on the sky of the average orientation
of the RSS. PA$_{\rm SWS}$: measured position angle on the sky of the SWS. 
PA$_{\rm RV}$: computed position angle on the sky of the Sun-comet radius vector. 
PA$_{\rm +V}$: computed position angle on the sky of the positive velocity vector.  
NLp: NL point sequential number (Fig.~\ref{fig1}). (1$-\mu$): radiation pressure acting on
the dust grain. $\tau$:  days elapsed between ejection of the dust grain from the comet
nucleus and observation. $d$~$[^{\circ}]$, $d$~[10$^6$~km]: angular (in the plane of the 
sky) and linear (in the plane of the comet orbit) distance from the nucleus of the 
computed NL point, respectively. PA$_{\rm NL}$: position angle of the sky-projected 
NL point. oPA$_{\rm NL}$: orbital position angle of
the NL point. Position angles in the plane of the sky are measured from north to east, 
as usual, whereas the ones in
the plane of the comet orbit (prefix o) are measured  counterclockwise from the 
Sun-comet prolonged radius vector
({r$'$}).
}
\label{tab2}
\begin{tabular}{c c cccc cccc cc}
\hline\hline
\noalign{\smallskip}
\multicolumn{1}{c}{No.} &
\multicolumn{1}{c}{PA$_{\rm RSS}$[$^{\circ}$]} &
\multicolumn{1}{c}{PA$_{\rm SWS}$[$^{\circ}$]} &
\multicolumn{1}{c}{PA$_{\rm RV}$[$^{\circ}$]} &
\multicolumn{1}{c}{PA$_{\rm +V}$[$^{\circ}$]} &
\multicolumn{1}{c}{NLp} &
\multicolumn{1}{c}{(1$-\mu$)} &
\multicolumn{1}{c}{$\tau$[days]} &
\multicolumn{1}{c}{$d~[^{\circ}]$} &
\multicolumn{1}{c}{PA$_{\rm NL}$[$^{\circ}$]} &
\multicolumn{1}{c}{$d$[10$^6$~km]} &
\multicolumn{1}{c}{oPA$_{\rm NL}$[$^{\circ}$]} \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
%  &       &       &        &        &   &       &       &       &        &       &        \\
1 & 299.9 & 122.5 & 125.01 & 307.61 & 1 & 0.01  & 17.87 & 0.259 & 300.23 & 1.385 & 280.97 \\
  &       &       &        &        & 2 & 0.02  & 17.99 & 0.510 & 300.09 & 2.775 & 280.11 \\
  &       &       &        &        & 3 & 0.03  & 18.12 & 0.753 & 299.94 & 4.172 & 279.24 \\
  &       &       &        &        & 4 & 0.04  & 18.26 & 0.986 & 299.79 & 5.573 & 278.36 \\
  &       &       &        &        & 5 & 0.05  & 18.39 & 1.210 & 299.62 & 6.981 & 277.47 \\
%  &       &       &        &        &   &       &       &       &        &       &        \\
2 & 303.3 & 123.6 & 124.41 & 305.17 & 1 & 0.001 & 19.35 & 0.035 & 303.33 & 0.158 & 283.84 \\
  &       &       &        &        & 2 & 0.002 & 19.36 & 0.069 & 303.33 & 0.316 & 283.76 \\
  &       &       &        &        & 3 & 0.003 & 19.37 & 0.103 & 303.32 & 0.475 & 283.67 \\
  &       &       &        &        & 4 & 0.004 & 19.38 & 0.138 & 303.32 & 0.633 & 283.58 \\
  &       &       &        &        & 5 & 0.005 & 19.39 & 0.172 & 303.32 & 0.791 & 283.50 \\
  &       &       &        &        & 6 & 0.006 & 19.40 & 0.206 & 303.32 & 0.949 & 283.41 \\
  &       &       &        &        & 7 & 0.007 & 19.41 & 0.240 & 303.31 & 1.108 & 283.32 \\
%  &       &       &        &        &   &       &       &       &        &       &        \\
3 & 306.7 & 125.0 & 122.37 & 298.17 & 1 & 0.001 & 23.62 & 0.052 & 306.68 & 0.210 & 287.86 \\
  &       &       &        &        & 2 & 0.002 & 23.63 & 0.104 & 306.68 & 0.420 & 287.77 \\
  &       &       &        &        & 3 & 0.003 & 23.64 & 0.156 & 306.69 & 0.630 & 287.68 \\
  &       &       &        &        & 4 & 0.004 & 23.65 & 0.208 & 306.70 & 0.840 & 287.60 \\ 
\hline
\end{tabular}
\end{table}