Profiles of the Lyman absorption lines least contaminated by airglow emission and H₂ absorption. Fluxes are in ergs cm⁻² s⁻¹ Å⁻¹. Each line is identified by its rest wavelength and shifted vertically by ﹩2\times 10^{-14}﹩ to provide separation from the mean profile (thick solid line). Note the flat‐bottomed saturated absorption profiles and the large width in velocity.