Sky science
Skyglow
Direct answer
Skyglow is diffuse night-sky brightness produced by artificial light, airglow, scattered moonlight, and other broad sources.
It is background light that reduces celestial contrast.
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At a glance
- Found in
- Astronomy & Skywatching
- Related
- Atmospheric Refraction, Airmass, Zodiacal Light, Gegenschein
It is background light that reduces celestial contrast.
A scientific orientation to scale, light, or motion; the article supplies the precise definition.
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The story behind Skyglow
Electric lighting dramatically expanded artificial skyglow around settlements.
A one-minute story
The Wandering Stars
How the moving planets were watched, named and found, and what a transit is.
Why Skyglow matters
Skyglow controls which faint objects and structures remain detectable.
How to read Skyglow
Identify artificial and natural components instead of treating all glow alike.
Skyglow in practice: an example
A galaxy disappears from view when its surface brightness approaches the bright sky background.
Where readings of Skyglow go wrong
A clouded urban sky can be brighter because clouds scatter city light.
Sources and editorial method
Research references used for this entry include:
- NASA Science: Night Lights - NASA observing context for zodiacal light, airglow, aurora, and other dim night-sky light.
- NASA Science: Skywatching FAQ - NASA guidance for observing stars, planets, constellations, and changing sky events.
- Source
- The Great Almanac Dictionary
- Category
- Astronomy & Skywatching
- Last updated
- 2026-09-26
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Common questions
What is skyglow?
Skyglow is diffuse night-sky brightness produced by artificial light, airglow, scattered moonlight, and other broad sources.
What do people get wrong about skyglow?
A clouded urban sky can be brighter because clouds scatter city light.
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