\begin{table}%t3
\caption{\label{obstrat}Observational strategy.}
%\centering
\small    
    \begin{tabular}{r c l c}
      \hline \hline
      Redshift range & $T_{\rm exp(LRB)}$ (s) &HR grism & $T_{\rm exp(HR)}$ (s) \\[1mm]
      \hline
      $z<0.100$       & 500& VHR-R &1000 \\
      $0.100<z<0.175$ & 750& VHR-R &1500 \\
      $0.175<z<0.200$ & 750& VHR-I &1500 \\
      $0.200<z<0.300$ &1000& VHR-I &2000 \\
      \hline
    \end{tabular}
\end{table}