Visual Observations of Nightglow from Manned Spacecraft

Abstract

The luminous band around the horizon noted by J. Glenn in the first U.S. manned orbital flight is attributable to airglow. Dip-of-the-horizon measurements on the star γ Ursae Majoris showed that the band is centered at an elevation of 91 kilometers or somewhat higher. The edge-on brightness of the airglow layer was 6 x 10^-7 candles per square centimeter.