\begin{table}%t1
%\centering

\caption{\label{tab:resol}Resolution of the simulations.}
\begin{tabular}{r|lr|c}
\hline
\hline
 & \multicolumn{2}{|c|}{Resolution} & \\
Time [orbits] & \multicolumn{1}{|l}{$N_{\rm rings} \times N_{\rm sectors}$}
& $\delta r/r=\delta\theta$ & \multicolumn{1}{|c}{Designation} \\
\hline
from   0 to 150: & $115 \times 393$ & $0.016$ & initialisation\\
from 150 to 250: & $230 \times 786$ & $8 \times 10^{-3}$ & low\\
from 250 to 325: & $460 \times 1572$ & $4 \times 10^{-3}$ & middle\\
from 325 to 400: & $920 \times 3144$ & $2\times 10^{-3}$ & high\\
from 400 to 477: & $1840 \times 6288$ & $10^{-3}$ & very high\\
\hline
\end{tabular}
\end{table}