\begin{table}%t3
%\centering
\par
	\caption{\label{tab:rdng}Readout noise and gain. where L and R stand for left and right CCDs output.}
		\begin{tabular}{l c c c c  }
\par
		\hline\hline
			CCD name  & A1L & A1R & A2L& A2R  \\
			\hline
			Readout noise  &  4.34& 4.26 & 4.25 & 4.36  \\
			(ADU/pixel/readout) & & & &  \\
			\hline
			Gain (${\rm e}^- /{\rm ADU}$) &  2.04 & 2.05 & 1.99 & 1.99  \\
			\hline%\hline
			CCD name & E1L & E1R & E2L& E2R \\
			\hline
			Readout noise & 5.5 & 5.4 & 5.5 & 5.3 \\
			(ADU/pixel/readout) & & & & \\
			\hline
			Gain (${\rm e}^- /{\rm ADU}$) & 2.06 & 2.05 & 2.15 & 2.14 \\
			\hline
		\end{tabular} 
\end{table}