Our COS G130M spectrum of the M87 filament, divided into segments B (top) and A (bottom) for visual clarity. We have binned the spectrum in this plot into 0.70 Å bins, and display 1σ errors on each bin as described in the text (Sect. 2). Prominent emission lines are identified and discussed in Sects. 3 and 4, and airglow lines are indicated with the shaded red regions and identified with red text.