Skyglow

sky glowartificial skyglowcity lights reflecting upwards into the skiesglowlight pollutionoutshinespristine night skies
Skyglow (or sky glow) is the diffuse luminance of the night sky, apart from discrete light sources such as the Moon and visible individual stars.wikipedia
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Light pollution

light-pollutedglarelight
It is a commonly noticed aspect of light pollution.
Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, and skyglow.

International Dark-Sky Association

International Dark SkyIDAInternational Dark Sky Park
Much discussion in the lighting industry and even by some dark-sky advocacy organizations (e.g. International Dark-Sky Association) of the sky glow consequences of replacing the currently prevalent high-pressure sodium roadway lighting systems with white LEDs neglects critical issues of human visual spectral sensitivity, or focuses exclusively on white LED light sources, or focuses concerns narrowly on the blue portion (
Light that shines into the eyes is called glare and light shining into the night sky above the horizon causes skyglow.

Night sky

night skiessky''' of the Earthsky of Earth
Skyglow (or sky glow) is the diffuse luminance of the night sky, apart from discrete light sources such as the Moon and visible individual stars.
Optical filters and modifications to light fixtures can help to alleviate this problem, but for optimal views, both professional and amateur astronomers seek locations far from urban skyglow.

Sky quality meter

Amateurs also increasingly use Sky Quality Meters (SQM) that measure in astronomical photometric units of visual (Johnson V) magnitudes per square arcsecond.
It is used, typically by amateur astronomers, to quantify the skyglow aspect of light pollution and uses units of "magnitudes per square arcsecond" favored by astronomers.

Dark-sky movement

dark skiesdark-skyDark Sky
Dark-sky movement
The movement started with professional and amateur astronomers alarmed that nocturnal skyglow from urban areas was blotting out the sight of stars.

Light-emitting diode

LEDLEDslight emitting diodes
Predominantly because of this effect, white light sources such as metal halide, fluorescent, or white LED can produce as much as 3.3 times the visual sky glow brightness of the currently most-common high-pressure sodium lamp, and up to eight times the brightness of low-pressure sodium or amber Aluminium gallium indium phosphide LED.
Light pollution: Because white LEDs emit more short wavelength light than sources such as high-pressure sodium vapor lamps, the increased blue and green sensitivity of scotopic vision means that white LEDs used in outdoor lighting cause substantially more sky glow.

Commission for Dark Skies

Campaign for Dark Skies (CfDS)
The campaign was founded in 1989 by amateur astronomers as a sub-section of the BAA specialising in combatting skyglow.

A Beautiful Planet

Beautiful Planet, A
A Beautiful Planet utilizes oversized IMAX screens to show some of the most notable cities worldwide lit up by nighttime skyglow, massive lightning storms seen from above the clouds, a dramatic glimpse into the eye of Super Typhoon Maysak, polar auroras viewed from low Earth orbit, the Great Lakes of North America locked in ice and snow, and reefs just below the surface of the turquoise Caribbean Sea.

Dark-sky preserve

Dark Sky Parkdark sky preserveBeaver Hills Dark Sky Preserve
Canada has established an extensive standard for dark sky preserves that addresses lighting within the DSP and influences from skyglow from urban areas in the region.

Aircraft camouflage

aircraftcamouflagecamouflage the aircraft
Some air forces such as the German Luftwaffe varied their paint schemes to suit differing flight conditions such as the skyglow over German cities, or the sands of the Mediterranean front.

Twilight

civil twilightastronomical twilightnautical twilight
However, in other places, especially those with skyglow, astronomical twilight may be almost indistinguishable from night.

Limiting magnitude

magnitude limited
The International Dark-Sky Association has been vocal in championing the cause of reducing skyglow and light pollution.

Globe at Night

Skyglow prevents large fractions of the Earth's population from viewing the Milky Way, which drove the development of much of ancient science, mythology, and religion.

Steve (atmospheric phenomenon)

STEVEStrong Thermal Emission Velocity EnhancementManoah Steves Elementary School
In August 2018, researchers determined that the phenomenon's skyglow was not associated with particle precipitation (electrons or ions) and, as a result, could be generated in the ionosphere.

Night

nighttimenight timeovernight
The glow provided by artificial lighting is sometimes referred to as light pollution because it can interfere with observational astronomy and ecosystems.

Citizen science

citizen scientistscitizen scientistcitizen-science
Observations of comets and stars are also used to measure the local level of artificial skyglow.

Full moon

Purnimaharvest moonfull
It is a poor time for other observations because the bright sunlight reflected by the Moon, amplified by the opposition surge, then outshines many stars.

Ecological light pollution

adverse ecological effectsartificial lightsFatal Light Awareness Program
The most acute affects are directly next to streetlights and lit buildings, but the diffuse light of skyglow can extend out to hundreds of kilometers away from city centers.

Stray light

light that straysstray-light
In optical astronomy, stray light from sky glow can limit the ability to detect faint objects.

National Dark-Sky Week

National Dark-Sky Week (NDSW)
Skyglow, a hazy glow produced by the reflection water molecules in the air that encompasses cities which prevent the night sky to be fully seen.

Te Raekaihau Point

The point is relatively free of light pollution, with little nearby population, no street lighting, and low adjacent population causing sky glow in the southern direction of Cook Strait.

OH-Suppressing Infrared Integral Field Spectrograph

10-meter Keck I telescopeOSIRIS
The 'OH suppressing' portion of the name refers to the fact that OSIRIS has sufficient spectral resolution that sky glow from OH molecules can be separated and removed from the spectra of the science targets.

Sky brightness

ambient brightnessbrighteningbrightness
Sources of the night sky's intrinsic brightness include airglow, indirect scattering of sunlight, scattering of starlight, and light pollution.

2018 in science

2018
Researchers report that the skyglow of STEVE ("Strong Thermal Emission Velocity Enhancement"), an atmospheric optical phenomenon appearing as a purple and green light ribbon in the sky, and not an aurora, is not associated with particle precipitation (electrons or ions) and, as a result, could be generated in the ionosphere.