[11.7.3]

The brightening of the night sky that results from the scattering and reflection of light from the constituents of the atmosphere (gaseous molecules and aerosols), in the direction of the observer. It has two separate components: natural sky glow and artificial sky glow.

11.7.3.1 natural sky glow

That part of sky glow which is attributable to natural sources. It is composed of starlight, zodiacal light (scattering of sunlight from dust in the solar system), and airglow (radiation from luminescent processes in the earth’s upper atmosphere).

11.7.3.2 artificial sky glow

That part of sky glow which is attributable to scattering of light from human-made sources of radiation (e.g., outdoor electric lighting), including radiation that is emitted directly upward and radiation that is reflected from surfaces.

« Back to Definitions Index