A rocket-borne photometric investigation of the oxygen lines at 5577 Å and 6300 Å, the sodium D-lines and the continuum at 5300 Å in the night airglow

The relative variations between 82 km and 205 km in the emission rates of nightglow radiation features at 5300 Å, 5577 Å, 5893 Å and 6300 Å have been photometrically measured from a Skylark rocket flown from Woomera, S. Australia at 2053 hours CST (1123 hours GMT) on 18 October, 1965.

Emission profiles obtained for the first three features show that these layers have their centre of intensity at, respectively, 94.0 ± 1 km, 94.5 ± 0.5, and 98.0 ± 2 km. The results further indicate that not more than 10% of the 6300 Å radiation was emitted below apogee at 205 km.

By virtue of a rather complicated vehicle motion—almost a slow tumble in the vertical plane—evidence is adduced which suggests that differences between these profiles and those of previous flights could be explained by insufficient or incorrect account being then taken of the contamination from extra-atmospheric sources such as starlight and galactic light.

Regarding the continuum, it is found that, depending on the particular region of sky background, up to 80% of the 5300 Å emission observed from the Earth may be extra-atmospheric in origin. Furthermore, of the extra-atmospheric component, again depending on the viewing direction in the sky, the emission intensity at 5577 Å may be from 10% to 50% greater than that at 5300 Å.

While it is to be expected that, before penetrating the layer, the zenithal emission intensity as registered by the photometers should remain constant, this constancy was not generally observed and the 5300 Å and 5577 Å photometers, both of which were independently duplicated, indicate an initial increasing emission intensity. Marked differences in the variation of each pair of photometers suggest that interpretation by means of aerosol absorption of the radiation in the 80 to 100-km region is incorrect and that the effect is probably instrumental in origin and of a temporary nature.