\begin{table}%t3
\caption{\label{tab3}Photometric errors associated with instrumental magnitudes}             % title of Table
%\centering
                          % used for centering table
\begin{tabular}{c c c c c}        % centered columns (4 columns)
\hline\hline                 % inserts double horizontal lines
mag & $\Delta m$ & & mag & $\Delta  m$  \\    % table heading 
\hline                        % inserts single horizontal line
19.000 &	0.007 &&23.000 &	0.057 \\
19.500 &	0.008&&23.500 &	0.093\\
20.000 &	0.009&&24.000 &	0.117\\
20.500 &	0.012&&24.500 &	0.190\\
21.000 &	0.015&&24.800 &     0.215\\
21.500 &	0.021&&25.000 &	0.310\\
22.000 &	0.027&&25.500 &	0.530\\
22.500 &	0.035&&26.000 &	0.869\\
\hline                                    
\end{tabular}
\end{table}