\begin{table}%tA.1
\caption{\label{log}Logbook of our spectroscopic observations of the three HgMn~stars.}
%\centering
\par
\begin{tabular}{cccc}
\hline \hline\noalign{\smallskip}
& $N$ & HJD begin & HJD end  \\
\hline
HD~11753 & 76 & 51~816 & 51~829 \\
& 28 & 51~881 & 51~894 \\
& 6  & 51~942 & 51~948 \\
& 3  & 52~111 & 52~123  \\
\hline 
HD~53244 & 56 & 51~816 & 51~829 \\
& 18 & 51~881 & 51~893 \\
& 29 & 51~940 & 51~953 \\
\hline 
HD~221507 & 68 & 51~816 & 51~829 \\
& 31 & 51~881 & 51~894 \\
& 6 & 52~110& 52~122 \\ 
\hline
\end{tabular}
\tablefoot {$N$ denotes the number of observations and the HJD is given with respect to HJD$_0$~=~2~400~000.}
\end{table}