\begin{table}%t9
\caption{Electron temperature indicators in NGC~3242.\label{tab9}}
%\begin{flushleft}
%\centerline
 {
\begin{tabular}{lcccc}
\hline
\hline
 Ion & Ioniz. & Lines& Observed & $T_{{\rm e}}$\\
 & Pot. (eV)& used$\dagger$ &ratio  & (K) \\
\hline
\ion{[N}{ii]}  & 14.5 & 5755/6584 & 0.0211 & 11~000 \\
\ion{[S}{iii]} & 23.3 & 6312/18.7 & 0.0.075 & 11~800 \\
\ion{[Ar}{iii]} & 27.6 & 7136/21.8 & 20.3 & 10~600\\
\ion{[O}{iii]} & 35.1 & 4363/5007 & 0.0106 & 11~780\\
\ion{[O}{iii]} & 35.1 & 1663/5007  & 0.0099 & 10~800\\
\ion{[O}{iii]} & 35.1 & 5007/51.8  & 7.90 & 11~000\\
\ion{[Ne}{iii]} & 41.0 & 3869/15.5 & 0.89 & 11~000\\
\ion{[O}{iv]}   & 54.9 & 1400/25.9 & 0.016 & 12~000:\\
\hline
\end{tabular}}
\par
\smallskip
: Indicates uncertain value.\\ 
$\dagger$ When the wavelength has 4~figures it has the 
units of Angstrom and 3~figures is micron.
\end{table}