\begin{table}%t1
%\centering
\par
\caption{General properties of the data. The dates of observations and the 
corresponding data sets (numbers usually refer to individual nights; for
exceptions see text) are presented in Cols.~2 and 3, respectively. Column~4 gives the total number of spectra available for the analysis, Col.~5 their 
spectral resolution ($FWHM$), Col.\ 6 the telescope used for the observations, 
and the last column lists references concerning the previous publication of the
data sets.}\label{data_tab}
\begin{tabular}{l l l l l l l} 
\hline\hline
star & dates & sets & $n_{\rm sp}$ & $\Delta\lambda$ [{\AA}] 
& telescope & reference\\ 
\hline 
\object{AK Cnc} & 1995-03-19, 21, 22        & 1--3           & 40 & 4.5 
& 2.5 m LCO & Arenas \& Mennickent (\cite{arenmenn98})\\
\object{WX Cet} & 1992-12-07, 08, 10        & 1--3           & 37 & 2.0 
& 2.2 m ESO/MPI & Mennickent (\cite{menn94})\\
\object{AQ Eri} & 1992-12-11                & 1(a--c)        & 44 & 2.0 
& 2.2 m ESO/MPI & Mennickent (\cite{menn95b})\\
\object{VW Hyi} & 1994-10-15 to 17          & 1--3           & 64 & 1.1
& 1.9 m SAAO & Tappert (\cite{tapp99}) \\
\object{RZ Leo} & 1995-02-10, 11, 03-21, 23 & 1a, 1b, 2a, 2b & 46 & 6.0, 4.5 
& 2.2 m ESO/MPI, 2.5 m LCO & Mennickent \& Tappert (\cite{menntapp01})\\
\object{TU Men} & 1992-12-09, 10, 12, 14    & 1--4           & 67 & 2.0 
& 2.2 m ESO/MPI & Mennickent (\cite{menn95a})\\
\object{HS Vir} & 1998-05-30                & 1              & 34 & 2.5 
& 3.5 m NTT & Mennickent et~al.\ (\cite{menn+99b})\\
\hline
\end{tabular} 
\end{table}