\begin{table}%t1
\caption{The group corrections d$t$, d$\varphi$, and d$z$.}\label{tab1}
%\centerline
{
\begin{tabular}{ c rrrrrrrrrrrr c }
     \hline  \hline
 Group    & 0~& 2~& 4~& 6~& 8~& 10&12&14 &16 &18 & 20 & 22& Closing \\
     ~    & ~ & ~ & ~ & ~ & ~ & ~ &~ &~  &~  &~  &~   & ~ & error \\
     \hline
d$t(0.0001^{\rm s})$         &--14&--19& 0 & 2 &--9 & 11& 1 & 5 & 12&  6& 12& --7&--16~~\\
$\sigma_t(\pm0.0001^{\rm s})$& 7 & 7 & 7 & 7 & 7 & 7 & 7 & 7 & 7 & 7 & 7 & 7 & 24~~\\
d$\varphi$(0$.001''$)  & 11& --6& --6& 20&--15&--16& 3 & --2& 13& 9 & 1 &--11&--92~~\\
$\sigma_{{\rm d}\varphi}$($\pm$0$.001''$)&10&10& 9& 9& 9& 9& 9& 9&10&10&10&10& 33~~\\
d$z$(0$.001''$)          & 19&--10&--15&--16& 3 & 3 & 25& 6 & --4& 6 & --7&--10& 91~~\\
$\sigma_{{\rm d}z}$($\pm$0$.001''$)& 7& 7& 7& 7& 7& 7& 6& 7& 7& 7& 7& 7& 24~~\\
   \hline
 \end{tabular}}
\medskip
 From Table~\ref{tab1}, we can see that the closing error of d$z$ is very small.
 \end{table}