Detection of the interstellar OH⁺ radical in the spectrum toward CPD −32°1734. Spectra toward HD 169454 and BD −14°5037 are shown as well. All spectra are normalized to a continuum level of 1.0 and rebinned to a heliocentric wavelength scale. The OH⁺, CH⁺, and CN absorption lines toward CPD −32°1734 are explicitly identified. Synthetic stellar spectra obtained from the models of Gummersbach & Kauffer (1993) are shown as red continuous curves.