\begin{table}%t8
\caption {\label{orbit}New and updated orbital elements of the spectroscopic binaries.}
$$
 {\begin{tabular}{lrr@{.}lr@{.}lr@{.}lr@{.}lr@{.}lr@{.}lr@{.}lr@{.}lr@{.}lr@{.}ll}
\hline\hline\noalign{\smallskip}
 Cluster & No. & \multicolumn{2}{c}{$P$} & \multicolumn{2}{c}{$T$} & \multicolumn{2}{c}{$\gamma$}
    & \multicolumn{2}{c}{$e$}  & \multicolumn{2}{c}{$\omega$} & \multicolumn{2}{c}{$K_1$} 
    & \multicolumn{2}{c}{$K_2$} & \multicolumn{2}{c}{$f(m)$} & \multicolumn{2}{c}{$a\sin i$} 
    & \multicolumn{2}{c}{$\sigma$} & $n_{\rm obs}$ \\
\hline\noalign{\smallskip}
Alpha Per &  143 &   61&1458   & 45~994&781 &  +5&26 & 0&095 & 133&4 & 31&56 & \multicolumn{2}{c}{ } & 0&0196 &  2&64  & 0&56 & 18 \\
          &      &    0&0011   &     0&063 &   0&14 & 0&006 &   4&2 &  0&20 & \multicolumn{2}{c}{ } & 0&0004 &  0&19  & \multicolumn{2}{c}{ } &  \\
Alpha Per &  457 &  202&38     & 45~868&7   &  --3&29 & 0&327 & 328&1 & 11&21 & \multicolumn{2}{c}{ } & 0&0250 &  29&5  & 1&1 & 25 \\
          &      &    0&14     &     3&2   &   0&23 & 0&026 &   5&5 &  0&30 & \multicolumn{2}{c}{ } & 0&0027 &   1&1  & \multicolumn{2}{c}{ } &  \\
Alpha Per &  848 &   89&812    & 48~452&2   &  -- 0&64 & 0&225 &  26&8 & 28&87 & \multicolumn{2}{c}{ } & 0&399  & 186&7  & 0&50 & 30 \\
          &      &    0&19     &     1&4   &   0&34 & 0&018 &   5&0 &  0&82 & \multicolumn{2}{c}{ } & 0&016  &   2&6  & \multicolumn{2}{c}{ } &  \\ 
Pleiades  &  173 &  480&82     & 44~550&6   &  +5&33 & 0&108 & 214&2 & 15&88 & 16&87 & 0&1964 & 104&4 & 0&98 & 48 \\   
          &      &    0&38     &     6&7   &   0&10 & 0&009 &   4&9 &  0&17 &  0&20 & 0&0069 &   1&3 & \multicolumn{2}{c}{ } &  \\  
Pleiades  &  320 &  756&4      & 44~488&1   &  +5&94 & 0&316 & 289&1 & 10&93 & \multicolumn{2}{c}{ } & 0&0876 & 107&8  & 0&81 & 28 \\
          &      &    1&3      &     7&2   &   0&16 & 0&019 &   4&5 &  0&24 & \multicolumn{2}{c}{ } & 0&0077 &   3&3  & \multicolumn{2}{c}{ } &  \\
Pleiades  &  522 &   23&8353   & 44~993&1   &  +6&67 & 0&102 & 19&76 &  4&86 & \multicolumn{2}{c}{ } & 0&000279 & 1&583 & 0&56 & 22 \\
          &      &    0&0034   &     1&7   &   0&13 & 0&032 & 27&94 &  0&17 & \multicolumn{2}{c}{ } & 0&000032 & 0&060 & \multicolumn{2}{c}{ } &  \\
\noalign{\smallskip}
\hline
\end{tabular}}
$$
\smallskip
Units: $P$: [days], $T$: Julian period, $\gamma$, K1, K2 and $\sigma \rm (O{-}C)$: [km~s$^{-1}$], $f(m)$: solar mass, $a \sin i$: Gm. The full table is also available in electronic form at the~CDS.
\end{table}