\begin{table}%t8
\caption{\label{tab:night_to_night_disp}Night-to-night dispersion, number of nights and resulting
statistical uncertainty for night sets~1 and~2.}
%\centering
\small
\begin{tabular}{lc|ccc|ccc}
\hline
\hline
      &      & \multicolumn{3}{c|}{Set \#1}               & \multicolumn{3}{c}{Set \#2} \\
field & band & $\sigma$ & \# nights & $\sigma / \sqrt{N}$&  $\sigma$ & \# nights & $\sigma / \sqrt{N}$ \\
\hline
D1    & $g$  & 0.007    &   13        & 0.002            &  0.009 & 28 & 0.002 \\ 
      & $r$  & 0.009    &   14        & 0.002            &  0.007 & 32 & 0.001 \\ 
      & $i$  & 0.007    &   11        & 0.002            &  0.009 & 36 & 0.002 \\ 
      & $z$  & 0.014    &   11        & 0.004            &  0.014 & 19 & 0.003 \\ 
\hline
D2    & $g$  & 0.007    &    8        & 0.003            &  0.007 & 13 & 0.002 \\ 
      & $r$  & 0.006    &   12        & 0.002            &  0.007 & 21 & 0.002 \\ 
      & $i$  & 0.004    &    7        & 0.002            &  0.008 & 25 & 0.002 \\ 
      & $z$  & 0.011    &    3        & 0.006            &  0.010 & 10 & 0.003 \\ 
\hline
D3    & $g$  & 0.002    &   15        & 0.002            &  0.009 & 29 & 0.002 \\ 
      & $r$  & 0.007    &   18        & 0.002            &  0.009 & 34 & 0.002 \\ 
      & $i$  & 0.006    &   14        & 0.002            &  0.013 & 40 & 0.002 \\ 
      & $z$  & 0.009    &    3        & 0.005            &  0.011 & 10 & 0.003 \\ 
\hline
D4    & $g$  & 0.008    &   18        & 0.002            &  0.009 & 30 & 0.002 \\ 
      & $r$  & 0.006    &   16        & 0.002            &  0.007 & 34 & 0.001 \\ 
      & $i$  & 0.006    &   11        & 0.002            &  0.008 & 29 & 0.002 \\ 
      & $z$  & 0.007    &    7        & 0.003            &  0.013 & 19 & 0.003 \\ 
\hline
\end{tabular} 
\end{table}