Light pollution

light-pollutedglarelightlight pollutedcity lightsbright suburban skiescity lightdark sitedark skiesdark-sky
Light pollution, also known as photopollution, is the presence of anthropogenic light in the night environment.wikipedia
478 Related Articles

Pollution

pollutedenvironmental pollutionpollution control
Light pollution is the adding-of/added light itself, in analogy to added sound, carbon dioxide, etc. Adverse consequences are multiple; some of them may not be known yet. Light pollution competes with starlight in the night sky for urban residents, interferes with astronomical observatories, and, like any other form of pollution, disrupts ecosystems and has adverse health effects.
Major forms of pollution include: Air pollution, light pollution, littering, noise pollution, plastic pollution, soil contamination, radioactive contamination, thermal pollution, visual pollution, water pollution.

Observatory

astronomical observatoryobservatoriesastronomical observatories
Light pollution competes with starlight in the night sky for urban residents, interferes with astronomical observatories, and, like any other form of pollution, disrupts ecosystems and has adverse health effects.
For optical telescopes, most ground-based observatories are located far from major centers of population, to avoid the effects of light pollution.

International Dark-Sky Association

International Dark SkyIDAInternational Dark Sky Park
In the 1980s a global dark-sky movement emerged with the founding of the International Dark-Sky Association (IDA).
Light pollution is the result of outdoor lighting that is not properly shielded, allowing light to be directed into the eyes and the night sky.

Skyglow

sky glowartificial skyglowcity lights reflecting upwards into the skies
Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, and skyglow.
It is a commonly noticed aspect of light pollution.

Night sky

night skiessky''' of the Earthsky of Earth
Light pollution competes with starlight in the night sky for urban residents, interferes with astronomical observatories, and, like any other form of pollution, disrupts ecosystems and has adverse health effects.
The visibility of celestial objects in the night sky is affected by light pollution.

Dark-sky preserve

Dark Sky Parkdark sky preserveBeaver Hills Dark Sky Preserve
These areas are supported by communities and organizations that are dedicated to reducing light pollution (e.g.Dark-sky preserve).
A dark-sky preserve (DSP) is an area, usually surrounding a park or observatory, that restricts artificial light pollution.

Milky Way

galaxyMilky Way Galaxyour galaxy
Apart from emitting light, the sky also scatters incoming light, primarily from distant stars and the Milky Way, but also the zodiacal light, sunlight that is reflected and backscattered from interplanetary dust particles.
Its visibility can be greatly reduced by background light, such as light pollution or moonlight.

Electric light

light bulblightbulbelectric lighting
Incorrect choice of fixtures or light bulbs, which do not direct light into areas as needed;
Low-pressure sodium lights are favoured for public lighting by astronomers, since the light pollution that they generate can be easily filtered, contrary to broadband or continuous spectra.

Sky brightness

ambient brightnessbrighteningbrightness
If a full moon is present, the sky brightness increases to about 18 magnitude/sq.
If light sources (e.g. the Moon and light pollution) were removed from the night sky, only direct starlight would be visible.

Light pollution in Hong Kong

Light pollution in Hong Kong was declared the 'worst on the planet' in March 2013.
Hong Kong has been named the world's worst city for light pollution.

Zodiacal light

zodiacal dustfalse dawnzodiacal band
Apart from emitting light, the sky also scatters incoming light, primarily from distant stars and the Milky Way, but also the zodiacal light, sunlight that is reflected and backscattered from interplanetary dust particles.
However, the glow is so faint that moonlight and/or light pollution outshine it, rendering it invisible.

Ecological light pollution

adverse ecological effectsartificial lightsFatal Light Awareness Program
When artificial light affects organisms and ecosystems it is called ecological light pollution.
Through the various effects that light pollution has on individual species, the ecology of regions is affected.

Polarized light pollution

This form of pollution is named polarized light pollution (PLP).
Polarized light pollution is a subset of the various forms of light pollution referring specifically to polarized light.

Luminous efficacy

efficacyefficientefficiency
Energy conservation advocates contend that light pollution must be addressed by changing the habits of society, so that lighting is used more efficiently, with less waste and less creation of unwanted or unneeded illumination.
Light pollution

Light-emitting diode

LEDLEDslight emitting diodes
Substitution of old lamps with more efficient LEDs using the same electrical power; and
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.

Over illumination

over-illuminationbright lightexcessive light
Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, and skyglow.
Light pollution

Astronomical filter

filtersSolar FilterAstronomical solar filter
Some astronomers use narrow-band "nebula filters", which only allow specific wavelengths of light commonly seen in nebulae, or broad-band "light pollution filters", which are designed to reduce (but not eliminate) the effects of light pollution by filtering out spectral lines commonly emitted by sodium- and mercury-vapor lamps, thus enhancing contrast and improving the view of dim objects such as galaxies and nebulae.
The broadband and narrowband filters transmit the wavelengths that are emitted by the nebulae (by the Hydrogen and Oxygen atoms), and are frequently used for reducing light pollution.

CieloBuio

Cielobuio-coordination for the protection of the night sky
The Italian Lombardy region, where only full cutoff design is allowed (Lombardy act no. 17/2000, promoted by Cielobuio-coordination for the protection of the night sky), in 2007 had the lowest per capita energy consumption for public lighting in Italy.
CieloBuio-coordinamento per la protezione del cielo notturno (Coordination for the protection of the night sky) is a non-profit organization that operates in Italy for the protection of the night sky by promoting a culture of eco-friendly lighting and raising public awareness about the phenomenon of light pollution.

Efficient energy use

energy efficiencyenergy efficientenergy-efficient
Specifically within the United States, over-illumination is responsible for approximately two million barrels of oil per day in energy wasted.
Light pollution

Security lighting

reduce crime at nightbrightly litsecurity lights
Disadvantages of low pressure sodium lighting are that fixtures must usually be larger than competing fixtures, and that color cannot be distinguished, due to its emitting principally a single wavelength of light (see security lighting).
While adequate lighting around a physical structure is deployed to reduce the risk of an intrusion, it is critical that the lighting be designed carefully as poorly arranged lighting can create glare which actually obstructs vision.

United States Naval Observatory Flagstaff Station

USNO FlagstaffNaval Observatory Flagstaff StationFlagstaff Station
One of the world's first coordinated legislative efforts to reduce the adverse effect of this pollution on the environment began in Flagstaff, Arizona, in the U.S. There, over three decades of ordinance development has taken place, with the full support of the population, often with government support, with community advocates, and with the help of major local observatories, including the United States Naval Observatory Flagstaff Station.
Flagstaff and Coconino County minimize northern Arizona light pollution through legislation of progressive code – which regulates local lighting.

Nocturnality

nocturnalnocturnal animalnocturnally
Light pollution poses a serious threat in particular to nocturnal wildlife, having negative impacts on plant and animal physiology.
The causes of these can be traced to distinct, sometimes overlapping areas: light pollution and spatial disturbance.

San Jose, California

San JoseSan Jose, CASan José
In 1980, for example, San Jose, California, replaced all street lamps with low pressure sodium lamps, whose light is easier for nearby Lick Observatory to filter out.
The lowest point in San Jose is 13 ft below sea level at the San Francisco Bay in Alviso; the highest is 2,125 ft. Because of the proximity to Lick Observatory atop Mount Hamilton, San Jose has taken several steps to reduce light pollution, including replacing all street lamps and outdoor lighting in private developments with low pressure sodium lamps.

Dark-sky movement

dark skiesdark-skyDark Sky
In the 1980s a global dark-sky movement emerged with the founding of the International Dark-Sky Association (IDA).
The dark-sky movement is a campaign to reduce light pollution.

Deep-sky object

deep skydeep sky objectdeep sky objects
Light pollution affects the visibility of diffuse sky objects like nebulae and galaxies more than stars, due to their low surface brightness.
Observing faint objects needs dark skies, so these relatively portable types of telescopes also lend themselves to the majority of amateurs who need to travel outside light polluted urban locations.