This paper describes the development and the construction, with optical details, of a high light power spectrograph suitable for the photography of the spectrum of the light of the moonless night sky and the spectra of auroral displays.Preliminary experiments carried out with it in England and in Canada are described. Typical spectrograms recorded by the instrument are shown.Suggestions for still further increasing the efficiency of the spectrograph are made. The advantages of using the spectrograph described are pointed out. Additional investigations of auroral phenomena, and an extension of those previously made are outlined.