\begin{table}%t1
\caption{\label{Tab1}Log of observations.}
%\centerline
 {\small \begin{tabular}{lrrr}
\hline \hline \noalign{\smallskip}
Objects$^1$& Spectrum mode & \multicolumn{2}{c}{Grism (exp.time (s)$\times$ \# exposures)} \\
\hline
\multicolumn{1}{c}{VLT FORS2}\\
%\hline
PN~4, PN~6 &Long slit & 600B  ($1500\times 3$)& 600RI  ($1500 \times 2$) \\
PN~10, PN~12, PN~14, PN~16, PN~18 & MXU & 600B   ($1800 \times 3$) &600RI  ($1500 \times 3$) \\
PN~19, PN~21, \ion{H}{ii} 15, \ion{H}{ii} 9 \\
\hline
\multicolumn{1}{c}{Gemini south}\\
%\hline
N: PN~5,  PN~7, \ion{H}{ii}  2, \ion{H}{ii}  4, \ion{H}{ii}  5& GMOS & B600 ($1100\times 4$) & R600$^2$ ($900 \times 4$)\\
%S: &GMOS& B600 & 550$\times$4\\
\hline
\end{tabular}}
\medskip  
 $^1$ Names from the list by Hern\'andez-Mart{\'\i}nez \& Pe\~na (2009); 
$^2$~R600 was used with the filter $GG455\_G0329$.
\end{table}