New measurements of the night airglow spectrum in the 1.5 μ region

Measurements of the spectra of the night airglow emission in the 1.40–1.65 μ region have been made at a spectral slit width of 25 A, with a grating spectrometer using a germanium photoconductive detector. The rotational fine structure of the 3,1 and 4,2 OH bands was partially resolved and the 2,0 OH band was observed for the first time. Rotational temperatures between 200 and 225°K were obtained from the P-branch of the 3,1 band. A mean value of 66 kR was obtained for the absolute zenith brightness of the 4,2 OH band. A van Rhijn measurement of the height of the OH emitting layer gave a value of 69 km.