\begin{table}%t3
%\centering
\par
\caption{Completeness and detection limits.\label{comp_limits}}% title of Table
     % is used to refer this table in the text
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                          % used for centering table
\begin{tabular}{ccc}        % centered columns (4 columns)
\hline\hline                 % inserts double horizontal lines
Filter & Completeness & Detection  \\    % table heading
\hline                        % inserts single horizontal line
\noalign{\smallskip}
 $J$ & 18.6 & 21.2 \\   % inserting body of the table
 $H$ & 19.1 & 21.5 \\
 $K_{\rm S}$ & 18.0 & 20.6 \\
 $L'$ & 13.5 & 14.1 \\
\hline                                   
\end{tabular}
\end{table}