Four occasional measurements of the altitude distribution of the 2796-2803-¿ doublet equatorial airglow have been made with the astronomical TD-1A satellite during winter 1973-1974. The observations indicate the presence of layers of Mg+ ions in the evening twilight F region in the African sector. Horizontal column densities reaching 8¿109Mg+ ions/cm2 are observed with peak altitudes varying from 230 to 480 km. Steep topside gradients with scale heights of about 5 km are observed on three occasions.