\begin{table}%t6
\caption{\label{tab6}Electron temperature indicators in NGC~6210.}
\small%\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 & 0.021 & 10~700 \\
\ion{[S}{iii]} & 23.3 & 6312/18.7 & 0.0.0475 & 10~000 \\
\ion{[Ar}{iii]} & 27.6 & 7136/8.99 & 0.839 & 8800\\
\ion{[N}{iii]}   & 29.6 & 1750/57.3 & 0.18  & 9400 \\
\ion{[O}{iii]} & 35.1 & 4363/5007 & 0.0056 & 9400\\
\ion{[O}{iii]} & 35.1 & 1663/5007  & 0.00466 & 9300\\
\ion{[O}{iii]} & 35.1 & 5007/51.8  & 7.18   &  9700 \\
\ion{[Ne}{iii]} & 41.0 & 3869/15.5 & 0.493 & 9300\\
\hline
\end{tabular}}
\medskip
$^\dagger$ When the wavelength has 4~figures it has the units of Angstrom and with 3~figures it is in microns.
\end{table}