\begin{table}%t2
%\centering
\par
\caption{\label{tab2}Observational parameters for both SDSS and GOODS(ACS) imaging.}
\begin{tabular}{l|  c c c| c c c c}        
\hline \hline  & \multicolumn{3}{c|}{SDSS} & \multicolumn{4}{c}{GOODS ACS}   \\
 \hline 	
$D$~=~telescope diameter (m) &\multicolumn{3}{c|}{2.5} &\multicolumn{3}{c}{2.4} \\ 
Band & {{\it u}}   & {{\it g}}  & {{\it r}} & {{\it B}}  & {{\it V}}  & {{\it i}} & {{\it z}}    \\ 
$T$~=~Expo-time (s) &53.907456 &53.907456 &53.907456 & 7200.00&5450.00 &7028.00 &18232.00   \\ 
$B$~=~sky background (mag) & 22.15&21.85 & 20.85&23.43 & 22.74&22.72 &22.36   \\ 
Filter {\it FWHM} ($\rm \rm \mathring{A}$) & 567.00&1387.00 & 1373.00&728.95 &1565.50 &1017.40 &1269.10   \\ 
Filter range ($\rm \mathring{A}$) & $\thicksim$1000.00&$\thicksim$1800.00 &$\thicksim$1500.00 &8780.00 & 2570.00&1910.00 &$>$3080.00   \\  \hline   
\end{tabular}
\end{table}