Mid-infrared spectra extracted over the 15−20 μm range for both lines of sight (see Appendix A for details). The spectrum of the NGC 7023 nebula where C₆₀ emission has been reported (Sellgren et al. 2010) is shown as a reference. The Chamaeleon spectrum is compared with a low resolution spectrum (IRS-LL) of NGC 7023, while the Scutum line of sight spectrum is compared to a medium resolution spectrum (IRS-SH) of NGC 7023, to be consistent with the observing modes used to obtain the spectra of interest here (see Appendix A). The positions of the C₆₀ vibrational bands are indicated with red vertical patches. The 16.4 μm attributed to PAH emission is indicated with a grey patch. Spectrally unresolved lines of molecular hydrogen and ions are also indicated with vertical dotted lines.