\begin{table}%t2
\caption{VLA map specifications for RX~Boo.}\label{tab:VLAspec} 
%\centerline
{\begin{tabular}{lrrrrr}
\hline\hline\noalign{\smallskip}
Date &  \multicolumn{3}{c}{\it HPBW} & rms & $S/N$ \\
 & maj.a.  & min.a. & PA  &  & \\
 & (\arcsec) & (\arcsec) & (\degr) & (Jy/b.) & \\
\noalign{\smallskip} \hline\noalign{\smallskip}
1990 Feb. & 0.090 & 0.077 & 86.23 & 0.015 & 3700 \\
1990 Jun. & 0.082 & 0.078 & 40.12 & 0.014 & 1700 \\
1991 Oct. & 0.305 & 0.092 & $-76.62$ & 0.025 & 190 \\
1992 Dec. & 0.077 & 0.072 & $-23.67$ & 0.027 & 130 \\
1995 Sep. & 0.127 & 0.084 & $-67.27$ & 0.009 & 580 \\
 \hline
\end{tabular}}
\smallskip
 {maj.a.}: half-power beam width (HPBW) for the major axis of the best-fit three-dimensional Gaussian component to the synthesised beam. \\
 {min.a.}: HPBW for the minor axis. \\
 {P.A.}: position angle of the major axis (E of N).\\
 {rms}: the root-mean-square noise fluctuations in signal-free channels in units of Jansky per beam area. \\
\emph{S/N}: signal-to-noise ratio or ``dynamic range'' in the channel with strongest signal.
\end{table}