\begin{table}%tC.18
\par
\caption{Like Table~\ref{naphthalene} for the perylene cation (C$_{20}$H$_{12}^+$).}
\label{perylene+}
%\begin{center}
\par
\begin{tabular}{cccc}
\hline \hline \noalign{\smallskip} 
& \multicolumn{3}{c}{Integrated flux} \\
\noalign{\smallskip} \cline{2-4} \noalign{\smallskip}
 &  & Red & IRAS\\
Peak & ISRF & Rectangle & 21282+5050\\
($\mu$m) & (W$~~$sr$^{-1}$) (\%) & (W$~~$sr$^{-1}$) (\%)& (W$~~$sr$^{-1}$) (\%) \\ 
\hline \noalign{\smallskip}
$\parallel$ 17.41 & $7.4\times 10^{-29}$ (0.71) & $4.1\times 10^{-27}$ (0.86) & $3.0\times 10^{-24}$ (0.48) \\
$\perp$ 18.75 & $1.0\times 10^{-28}$ (1.00) & $6.0\times 10^{-27}$ (1.24) & $4.1\times 10^{-24}$ (0.65) \\
$\parallel$ 18.99 & $2.7\times 10^{-29}$ (0.26) & $1.6\times 10^{-27}$ (0.32) & $1.1\times 10^{-24}$ (0.17) \\
$\perp$ 21.54 & $9.8\times 10^{-30}$ (0.09) & $5.8\times 10^{-28}$ (0.12) & $3.0\times 10^{-25}$ (0.05) \\
$\parallel$ 21.95 & $1.4\times 10^{-29}$ (0.13) & $7.8\times 10^{-28}$ (0.16) & $4.3\times 10^{-25}$ (0.07) \\
$[22.04]$ & $4.7\times 10^{-30}$ (0.05) & $2.1\times 10^{-28}$ (0.04) & -- \\
$[23.38]$ & $5.6\times 10^{-30}$ (0.05) & $3.0\times 10^{-28}$ (0.06) & -- \\
$[24.23]$ & $5.8\times 10^{-30}$ (0.06) & $3.4\times 10^{-28}$ (0.07) & -- \\
$[27.67]$ & $8.5\times 10^{-30}$ (0.08) & $4.1\times 10^{-28}$ (0.09) & -- \\
$[28.49]$ & $9.4\times 10^{-30}$ (0.09) & $4.4\times 10^{-28}$ (0.09) & -- \\
$[35.52]$ & $1.3\times 10^{-29}$ (0.13) & $5.8\times 10^{-28}$ (0.12) & -- \\
$\parallel$ 39.35 & $1.9\times 10^{-29}$ (0.18) & $1.2\times 10^{-27}$ (0.26) & $3.5\times 10^{-25}$ (0.06) \\
$[40.73]$ & $1.6\times 10^{-29}$ (0.16) & $6.3\times 10^{-28}$ (0.13) & -- \\
$[48.48]$ & $2.0\times 10^{-29}$ (0.19) & $6.8\times 10^{-28}$ (0.14) & -- \\
$\perp$ 57.15 & $4.3\times 10^{-29}$ (0.42) & $2.8\times 10^{-27}$ (0.58) & $1.2\times 10^{-24}$ (0.19) \\
$[67.82]$ & $2.5\times 10^{-29}$ (0.24) & $6.1\times 10^{-28}$ (0.13) & -- \\
$\perp$ 98.04 & $3.4\times 10^{-29}$ (0.32) & $2.2\times 10^{-27}$ (0.45) & $4.1\times 10^{-25}$ (0.07) \\
$[247.44]$ & $3.0\times 10^{-29}$ (0.29) & $1.1\times 10^{-28}$ (0.02) & -- \\
\hline 
\end{tabular}
%\end{center}
\par
\end{table}