\begin{table}%t1
\caption{\label{slog}Spectroscopic observation log for a~Cen.}
%\centering
\par
\small
 \begin{tabular}{ccrccccrc}
  \hline\hline
  \noalign{\smallskip}
 \multicolumn{2}{c}{4412--4488~\AA} & \multicolumn{2}{c}{$R = 93~000$} & & \multicolumn{2}{c}{7238--7321~\AA} & \multicolumn{2}{c}{$R = 158~000$} \\
 %\hline
 HJD & \multicolumn{2}{c}{Phase} & Exp. time & & HJD & \multicolumn{2}{c}{Phase} & Exp. time  \\
 (2~450~000+) & (Decimal) & (\degr)~~ & (s) & & (2~450~000+) & (Decimal) & (\degr)~~ & (s)   \\
  \hline   
  2801.8505 & 0.337 & 121.3 & 600 & & 2800.7844  & 0.216 & 77.6 & 600 \\
  2801.8579 & 0.338 & 121.6 & 600 & & 2801.7660  & 0.327 & 117.6 & 600 \\
  2802.8581 & 0.451 & 162.4 & 600 & & 2802.7766  & 0.441 & 158.9 & 600 \\ 
  2802.8655 & 0.452 & 162.7 & 600 & & 2803.7557  & 0.553 & 198.9 & 600\\
  2803.8453 & 0.563 & 202.7 & 600 & & 2804.7718  & 0.668 & 240.4 & 600\\
  2803.8529 & 0.564 & 203.0 & 600 & & 2805.7523  & 0.779 & 280.4 & 600 \\
  2804.8456 & 0.676 & 243.5 & 600 & & 2806.8027  & 0.898 & 323.3 & 600 \\
  2804.8531 & 0.677 & 243.8 & 600 & & 2807.8005  & 0.011 & 4.0 & 600 \\
  2805.8207 & 0.787 & 283.4 & 600 & & 2808.7530  & 0.119 & 42.9 & 600 \\
  2805.8282 & 0.788 & 283.7 & 600 \\
  2806.8490 & 0.904 & 325.3 & 900 \\
  2807.8477 & 0.017 & 6.1 & 900 \\
  2808.8297 & 0.128 & 46.2 & 600 \\
  2808.8370 & 0.129 & 46.5 & 600 \\
  \hline\\[-3.25mm]
 \multicolumn{2}{c}{6506--6620~\AA} & \multicolumn{2}{c}{$R = 95~000$} & & \multicolumn{2}{c}{6592--6702~\AA} & \multicolumn{2}{c}{$R = 96~000$} \\
 %\hline
 HJD & \multicolumn{2}{c}{Phase} & Exp. time & & HJD & \multicolumn{2}{c}{Phase} & Exp. time \\
 (2~450~000+) & (Decimal) & (\degr)~~& (s) & & (2~450~000+) & (Decimal) & (\degr)~~ & (s)  \\   
 \hline
 2801.8222  & 0.334 & 120.1 & 900 & & 2800.8628 & 0.225 & 80.9 & 900 \\
 2802.8313  & 0.448 & 161.3 & 900 & & 2801.7982 & 0.331 & 119.1 & 600 \\
 2803.8225  & 0.561 & 201.8 & 900 & & 2801.8055 & 0.332 & 119.4 & 600 \\
 2804.8245  & 0.674 & 242.7 & 600 & & 2802.8076 & 0.445 & 160.4 & 600 \\
 2805.7971  & 0.785 & 282.4 & 600 & & 2802.8148 & 0.446 & 160.6 & 600 \\
 2806.7459  & 0.892 & 321.1 & 900 & & 2803.7967 & 0.558 & 200.8 & 600 \\
 2807.7535  & 0.006 & 2.3 & 600 & & 2803.8043 & 0.559 & 201.1 & 600 \\
 2808.8151  & 0.127 & 45.6 & 600 & & 2804.8019 & 0.672 & 241.7 & 600 \\
  & & & &                                & 2804.8094 & 0.673 & 242.1 & 600 \\
  & & & &                                & 2805.7744 & 0.782 & 281.5 & 600 \\
  & & & &                                & 2805.7820 & 0.783 & 281.8 & 600 \\
  & & & &                                & 2806.7644 & 0.894 & 321.9 & 600 \\
  & & & &                                & 2806.7719 & 0.895 & 322.2 & 600 \\
  & & & &                                & 2807.7725 & 0.008 & 3.0 & 900 \\
  & & & &                                & 2808.7929 & 0.124 & 44.7 & 600 \\
  & & & &                                & 2808.8006 & 0.125 & 45.0 & 600 \\
  \hline
 \end{tabular}\vspace*{-0.5mm}
\end{table}