\begin{table}%t4
\caption{\label{tab:etadip}Measuring the significance of the dip
in visibility of~$\eta$ Corvi at 10--11.5~$\mu$m.}  
%%\centerline

 {\small \begin{tabular}{*{4}{c}}
\hline\hline
Baseline &
\multicolumn{3}{c}{Visibility} \\ name & 8--9~$\mu$m & 10--11.5~$\mu$m  & Ratio  \\
\hline
A & 1.016 $\pm$ 0.005 & 0.892 $\pm$ 0.004 & 0.877 $\pm$ 0.026 \\ 
B & 0.910 $\pm$ 0.003 & 0.818 $\pm$ 0.003 & 0.899 $\pm$ 0.027 \\
D1 & 0.841 $\pm$ 0.003 & 0.739 $\pm$ 0.003 & 0.879 $\pm$ 0.026 \\
D2 & 0.922 $\pm$ 0.003 & 0.801 $\pm$ 0.004 & 0.868 $\pm$ 0.026 \\ %\hline
$V_{\rm{res}}$ & 0.915 & 0.784 & 0.857  \\
\hline
\end{tabular}}
\medskip
A description of the calculation of the visibilities and errors is
given in the caption to Table~\ref{tab:69830visdip}. 
\end{table}