\begin{table}%t2
\caption{Field stars comparison.}
\label{field}
%\centering
\par
\begin{tabular}[h]{r r r r }
\hline  \hline
Nebula & 2\min.5 & 5\min~ & 10\min~  \\
\hline
SMC N81 &  56  & 359 & 1197 \\
N88 &  28  & 132 &  484 \\
N90 &  39  & 102 &  369 \\
N66 & 192  & 805 & 2883 \\
N70 & 142  & 581 & 2352 \\
\hline
\end{tabular}
\end{table}