\begin{table}%t6
\caption{\label{tab6}Electron temperature indicators in M~1-42.}
\small%\centering
\par
\begin{tabular}{lcccc}
\hline
\hline
 Ion & Ioniz. & Lines& Observed & $T_{{\rm e}}$\\
 & Pot. (eV)& Used &Ratio  & (K) \\
\hline
$[$\ion{N}{ii}$]$   & 14.5 & 5755/6584 & 0.0108 & 8400 \\
$[$\ion{S}{iii}$]$  & 23.3 & 6312/18.7 & 0.0079 & 7500 \\
$[$\ion{Ar}{iii}$]$ & 27.6 & 7136/21.8 & 4.39   & 6500\\
$[$\ion{O}{iii}$]$  & 35.1 & 4363/5007 & 0.0050 & 9300\\
$[$\ion{O}{iii}$]$  & 35.1 & 5007/51.8 & 2.83   & 7800\\
$[$\ion{Ne}{iii}$]$ & 41.0 & 3869/15.5 & 0.136  & 7000\\
\hline
\end{tabular}
\end{table}