\begin{table}%t2
\caption{\label{visib-table}Calibrated squared visibility measurements of $\eta$~Ser.}
 %\centerline
{\small  
\begin{tabular}{lccccc}
\hline \hline
\noalign{\smallskip}
MJD  & $B$  & PA & $V^2\pm \sigma$ & L1 \\
& (m) & ($^\circ$) & (\%) & \\
\hline
\noalign{\smallskip}
53~930.377 & 214.68  & $-7.77$ & $ 0.00715\pm 0.00041$ & \\ 
53~930.400 & 219.44  & $-13.90$ & $ 0.00781\pm 0.00020$ & \\ 
53~936.364 & 171.46  & $-38.16$ & $ 0.00924\pm 0.00053$ & $\bullet$\\ 
53~937.302 & 157.44  & $-32.36$ & $ 0.02710\pm 0.00114$ & $\bullet$\\ 
53~937.320 & 162.43  & $-34.71$ & $ 0.01978\pm 0.00093$ & $\bullet$\\ 
53~937.338 & 166.67  & $-36.46$ & $ 0.01272\pm 0.00065$ & $\bullet$\\ 
\hline
\end{tabular}}
\tablefoot{MJD: modified Julian date of the observation; $B$: projected
  baseline length; PA: azimuth of the projected baseline (counted
  positively from North to East); $V^2$: squared visibility; L1:
  ``$\bullet$'' means measurements obtained in the first lobe of the
  visibility.}
\end{table}