Airglow is an aurora-like phenomenon in the upper atmosphere caused by a variety of chemical reactions. It begins during the day when solar ultraviolet radiation ionizes atoms and molecules. At night, those same atoms and molecules glow as they re-capture lost electrons. The green in Beletsky's photo comes from oxygen atoms in a layer 90-100 km high; the red is probably associated with OH ions at an altitude of about 85 km. The wavy structure of the glow is due to high-altitude gravity waves, which alter the temperature and density structure of the upper atmosphere.
"Airglow is much less intense than aurora," continues Beletsky. "The display I saw looked, to the naked eye, like a series of black-and-white waving bands. The full color of the display was easily captured, however, by my digital camera."