\begin{table}%T1
\caption{\label{journal}Journal of our spectroscopic observations of WR~20a. The first and second columns provide the heliocentric Julian date (in the format HJD$ - 2~450~000$) and the orbital phase assuming a period of~$3.675$~days and adopting phase $\phi = 0.0$ as given in Table~\ref{tab-orbit}. The third column indicates whether the blue~($B$) or violet~($V$) spectral range was observed. The recentred and averaged primary and secondary radial velocities are given in Cols.~4 and~5 respectively (see text). Finally, the last column yields the weight that we assigned to the various {\it RV}~data in the orbital solution.}
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\par
\begin{tabular}{c c c r r c}
\hline\hline
Date & $\phi$ & Set-up & {\it RV}$_1$ & {\it RV}$_2$ & Weight \\
     &        &        & (km~s$^{-1}$) & (km~s$^{-1}$) & \\
\hline
2354.560 & 0.542 & $B$ &  $-11.7$ &  $-11.7$ & 0.1 \\
2355.600 & 0.825 & $V$ &   290.7  & $-319.3$ & 0.7 \\
3032.716 & 0.074 & $B$ & $-131.9$ &   182.9  & 0.2 \\
3032.742 & 0.081 & $V$ &     9.1  &     9.1  & 0.1 \\
3033.715 & 0.346 & $V$ & $-288.4$ &   277.4  & 0.7 \\
3033.739 & 0.353 & $B$ & $-285.1$ &   292.6  & 1.0 \\
3034.715 & 0.618 & $V$ &   235.8  & $-219.1$ & 0.7 \\
3034.741 & 0.625 & $B$ &   287.6  & $-265.5$ & 1.0 \\
3035.719 & 0.892 & $V$ &   269.3  & $-222.7$ & 0.7 \\
3035.746 & 0.899 & $B$ &   245.2  & $-219.4$ & 1.0 \\
3036.719 & 0.164 & $V$ & $-259.7$ &   287.0  & 0.7 \\
3036.743 & 0.170 & $B$ & $-302.6$ &   309.5  & 1.0 \\
3037.738 & 0.441 & $V$ &  $-78.3$ &  $-78.3$ & 0.1 \\
3037.762 & 0.447 & $B$ &  $-74.0$ &  $-74.0$ & 0.1 \\
3038.723 & 0.709 & $V$ &   363.5  & $-354.0$ & 0.7 \\
3038.746 & 0.715 & $B$ &   374.6  & $-375.9$ & 1.0 \\
3039.718 & 0.980 & $V$ &    12.4  &    12.4  & 0.1 \\
3039.752 & 0.989 & $B$ &  $-28.0$ &  $-28.0$ & 0.1 \\
3040.717 & 0.252 & $V$ & $-309.3$ &   368.4  & 0.7 \\
3040.741 & 0.258 & $B$ & $-336.1$ &   394.0  & 1.0 \\
3041.722 & 0.525 & $V$ &     4.3  &     4.3  & 0.1 \\
3041.747 & 0.532 & $B$ &    22.9  &    22.9  & 0.1 \\
3042.714 & 0.795 & $B$ &   375.4  & $-374.4$ & 0.2 \\
\hline
\end{tabular}
\end{table}