\begin{table}%t4 
\caption{Illustration of results underlying the mean radial
velocities $v_{\rm rad}$ in Table~\ref{tab:3} (cf. Eq.~(\ref{eq:v_rad})). The star HD~24970 (A0) was observed $N = 3$ times
and has $N_{\rm s} = 5$ suitable standard stars, giving rise to 5
radial velocities per exposure. These values are listed (in km~s$^{-1}$),
together with the spectral classifications and distances $d$ and
weights $w$ (see Eqs.~(\ref{eq:d}) and~(\ref{eq:w})) of the standard
stars. The distance-weighted mean radial velocities with their errors
are listed in the final column (in km~s$^{-1}$). Systematic
differences between columns in this table can be due to template
mismatch and/or incorrect literature radial velocities; in general,
systematic differences between lines in this table can be due to
random errors (statistics), instrumental shifts, and/or multiplicity
(not likely in this specific case).}
%%\centering
\par
 
\begin{tabular}{crrrrrr} 
\hline\hline 
\multicolumn{1}{r}{HD} & 
\multicolumn{1}{c}{10982} & 
\multicolumn{1}{c}{196724} & 
\multicolumn{1}{c}{196821} & 
\multicolumn{1}{c}{27638} & 
\multicolumn{1}{c}{58142} & 
\multicolumn{1}{c}{$v_{\rm rad}$}\\ 
\multicolumn{1}{r}{SpT} & 
\multicolumn{1}{c}{B9V} & 
\multicolumn{1}{c}{A0V} & 
\multicolumn{1}{c}{A0III} & 
\multicolumn{1}{c}{B9V} & 
\multicolumn{1}{c}{A1V} & 
\multicolumn{1}{c}{}\\ 
\multicolumn{1}{r}{$d=$} & 
\multicolumn{1}{c}{$1.00$} & 
\multicolumn{1}{c}{$0.00$} & 
\multicolumn{1}{c}{$1.00$} & 
\multicolumn{1}{c}{$1.00$} & 
\multicolumn{1}{c}{$1.00$} & 
\multicolumn{1}{c}{}\\ 
\multicolumn{1}{r}{$w=$} & 
\multicolumn{1}{c}{$0.50$} & 
\multicolumn{1}{c}{$1.00$} & 
\multicolumn{1}{c}{$0.50$} & 
\multicolumn{1}{c}{$0.50$} & 
\multicolumn{1}{c}{$0.50$} & 
\multicolumn{1}{c}{}\\ 
\hline 
{\rm Exposure\ } 1*           & 26.2~ & 27.8~ & 24.3~ & 21.4~ & 
22.8~ & $25.3 \pm 3.3$\\ 
{\rm Exposure\ } 2\phantom{*} & 24.1~ & 26.1~ & 21.6~ & 20.1~ & 
20.2~ & $23.2 \pm 3.5$\\ 
{\rm Exposure\ } 3\phantom{*} & 21.6~ & 23.8~ & 19.6~ & 16.9~ & 
18.4~ & $21.0 \pm 3.5$\\ 
\hline
\end{tabular} 
\label{tab:4} 
\end{table}