The earliest detections of interstellar and cometary species were made via electronic spectroscopy in the UV-visible region rather than rotational spectroscopy in the microwave and sub-mm regions. The brief report in 1941 of the identification of CH⁺ by Alex Douglas and Gerhard Herzberg alludes to an informal gathering at Yerkes Observatory at which Pol Swings reported that several lines near 4000 Å could not be matched with known spectra. Herzberg and Edward Teller noted the similarity to the isoelectronic species BH and suggested that CH⁺ could be the source of the lines. New spectra taken by Douglas & Herzberg at the University of Saskatchewan confirmed the identification. Swings used the same spectra to determine that CH⁺ was also present in comets. In 1987, Magain & Gillet reported the detection of CH⁺ in the Large Magellanic Cloud. It has also been detected with rotational spectroscopy by Cernicharo et al.