Cross-dispersion profiles for the two brightest lines in our FUV spectrum, along with the COS cross-dispersion line spread function and the cross-dispersion profile for Lyα airglow for comparison. These latter two profiles bracket the range of spatial extension in the cross-dispersion direction, with the lsf corresponding to zero extent and the airglow corresponding to uniformly aperture-filling emission. The filament approximately extends along the cross-dispersion axis in our observations. We infer standard deviations of 3.3 ± 0.1 pixels, 8.5 ± 0.2 pixels, 8.0 ± 0.2 pixels, and pixels for the four lines respectively, suggesting that Lyα and N V approximately extend along the entire cross-dispersion axis. This does not imply that they are similarly extended along the dispersion axis, however, and we expect that they are in fact not very extended in the dispersion direction.