Editing Dark-sky movement

{{Short description|Campaign against light pollution}}
The '''dark-sky movement''' is a [[social movement|campaign]] to reduce [[light pollution]]. The advantages of reducing light pollution include an increased number of stars visible at night, reducing the effects of electric lighting on the environment, improving the well-being,<ref>{{Cite journal|last1=Summers|first1=J. K.|last2=Smith|first2=L. M.|last3=Case|first3=J. L.|last4=Linthurst|first4=R. A.|date=June 2012|title=A Review of the Elements of Human Well-Being with an Emphasis on the Contribution of Ecosystem Services|journal=Ambio|volume=41|issue=4|pages=327–340|doi=10.1007/s13280-012-0256-7|issn=0044-7447|pmc=3393065|pmid=22581385|bibcode=2012Ambio..41..327S }}</ref> health<ref>{{Cite journal|last=Chepesiuk|first=Ron|date=January 2009|title=Missing the Dark: Health Effects of Light Pollution|journal=Environmental Health Perspectives|volume=117|issue=1|pages=A20–A27|issn=0091-6765|pmc=2627884|pmid=19165374|doi=10.1289/ehp.117-a20}}</ref> and safety<ref>{{Cite web|url=http://www.darksky.org/light-pollution/lighting-crime-and-safety/|title=Lighting, Crime and Safety|website=www.darksky.org}}</ref> of people and wildlife,<ref>{{Cite web|url=http://news.nationalgeographic.com/news/2003/04/0417_030417_tvlightpollution.html|archive-url=https://web.archive.org/web/20030419061453/http://news.nationalgeographic.com/news/2003/04/0417_030417_tvlightpollution.html|url-status=dead|archive-date=April 19, 2003|title=Light Pollution Taking Toll on Wildlife, Eco-Groups Say|website=news.nationalgeographic.com}}</ref> and cutting down on energy usage. [[Earth Hour]] and [[International Dark-Sky Week]] are two examples of such efforts.

The [[social movement|movement]] started with professional and amateur [[astronomer]]s alarmed that nocturnal [[skyglow]] from urban areas was blotting out the sight of stars. For example, the world-famous [[Palomar Observatory]] in California is threatened by sky-glow from the nearby city of [[Escondido, California|Escondido]] and local businesses.<ref>{{Cite web |title=Light Pollution |url=https://sites.astro.caltech.edu/palomar/community/lightpollution.html |access-date=2023-12-30 |website=sites.astro.caltech.edu}}</ref> For similar reasons, astronomers in Arizona helped push the governor there to veto a bill in 2012 which would have lifted a ban on illuminated billboards.<ref>[http://azdailysun.com/news/state-and-regional/astronomers-celebrate-veto-of-billboard-bill/article_e5f59f64-3a22-5881-8015-4babce8253b2.html AZ Daily Sun: "Astronomers celebrate veto of billboard bill"]{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

[[Nocturnal]] animals can be harmed by light pollution because they are biologically evolved to be dependent on an environment with a certain number of hours of uninterrupted daytime and nighttime. The [[over-illumination]] of the night sky is affecting these organisms (especially birds). This biological study of darkness is called [[scotobiology]].<ref>{{Cite web |title=EnviroNews Archives - Scotobiology – The Biology of Darkness |url=https://isebindia.com/05_08/05-01-3.html |access-date=2023-12-30 |website=isebindia.com}}</ref> Light pollution has also been found to affect human circadian rhythms.<ref>http://www.darksky.org/about-ida International Dark Sky Association: About the IDA</ref>

The dark-sky movement encourages the use of [[Light pollution#Improving lighting fixtures|full-cutoff fixtures]] that cast little or no light upward in public areas and generally to encourage communities to adopt lighting regulations. A 2011 project is to establish "dark sky oasis" in suburban areas.<ref>{{Cite web |last=Atkinson |first=Nancy |date=2011-12-11 |title=A Refreshing Idea! Vote for Enabling City Kids to See Starry Skies |url=https://www.universetoday.com/91721/a-refreshing-idea-vote-for-enabling-city-kids-to-see-starry-skies/ |access-date=2023-12-30 |website=Universe Today |language=en-US}}</ref>

== Dark-sky lighting ==
Dark-sky lighting is a concept important to the dark-sky movement, as it minimizes light pollution. The concept was started in the 1950s by the city of [[Flagstaff, Arizona|Flagstaff]], Arizona.<ref>{{Cite web |title=Flagstaff's Battle for Dark Skies – Flagstaff Dark Skies Coalition |url=http://www.flagstaffdarkskies.org/international-dark-sky-city/flagstaffs-battle-for-dark-skies/ |website=www.flagstaffdarkskies.org}}</ref> Flagstaff is a city of over 70,000 people, but because of its effectively controlled lighting, the skies are dark enough to see the Milky Way,<ref>{{Cite news|url=http://www.coloradoan.com/story/news/2016/09/27/save-our-stars-city-seeks-preserve-night-skies/90970492/|title=Save our stars: City seeks to preserve night skies in Fort Collins|work=Coloradoan}}</ref> and the light dome over the city viewed from some distance has been measured as less than 10% as bright as that over a similarly-sized city (Cheyenne, Wyoming) that has not sought to protect its night skies.<ref>{{cite web |last1=Pipkin |first1=Ashley |title=Measuring the color and brightness of artificial sky glow from cities using an all-sky imaging system calibrated with astronomical methods in the Johnson-Cousins B and V photometric systems |url=https://ui.adsabs.harvard.edu/abs/2017AAS...22923620P/abstract |website=ADS-Astrophysics Data System |publisher=American Astronomical Society |access-date=18 February 2024}}</ref><ref>{{cite web |last1=Luginbuhl |first1=Christian |title=The Flagstaff Solution |url=https://flagstaffdarkskies.org/the-flagstaff-solution/ |website=Flagstaff Dark Skies Coalition |publisher=Flagstaff Dark Skies Coalition |access-date=18 February 2024}}</ref> Lights should be shielded on the top and sides so light doesn't go up to the sky and only used when needed (use motion detectors and only the wattage necessary).<ref>{{Cite web|url=http://www.darksky.org/lighting/lighting-basics/|title=Outdoor Lighting Basics|website=www.darksky.org|language=en-US|access-date=2017-09-05}}</ref> To minimize the visual brightness of skyglow and reduce glare and most other biological impacts, amber-colored lighting is critical (such as formerly high- and low-pressure sodium, or now amber LED - see [[Skyglow#Dependence_on_light_source]]). The [http://www.darksky.org/ International Dark-Sky Association] certifies fixtures as dark sky friendly, and these will have the [http://www.darksky.org/fsa/ IDA Fixture Seal of Approval].

== Skyglow ==
{{main|Skyglow}}
[[File:México City at Night 2005.jpg|250px|thumb|right|[[Mexico City]] at night, showing skyglow bright enough to read a book outside]]
Skyglow is the illumination of the [[night sky]] or parts of it, resembling an orange "[[smog]]". It occurs from both natural and human-made sources.<ref name=cat>http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/lightpollution/skyGlow.asp Lighting Resource Centre: "What is sky glow?".</ref> Artificial skyglow is caused by the [[over-illumination]] of the sky from large city centres, shopping centres, or stadiums. It consists of light that is either emitted directly upward or reflected from the ground that is then scattered by dust and gas molecules in the atmosphere, producing a luminous background or light dome. These artificial skyglows cause the sky to be up to 100 times brighter in urban areas than a naturally dark sky that is unaffected by artificial light. Natural skyglow can come from [[Daylighting (architecture)|natural light]] sources, such as the [[sunlight|Sun]], the [[moonlight|Moon]], the [[starlight|stars]], or [[Aurora (astronomy)|aurora]]s.

Some communities are becoming aware of this problem and are putting forth efforts to minimize the hazy, orange skyglow. A community in particular is the city of [[Merritt, British Columbia]]. An article published July 8, 2010 states that they are making minor changes to lighting in and around Merritt, such as the installment of down-cast lighting to commercial buildings, as part of their light pollution abatement program.<ref name="merrittnews.net">{{Cite web |last=Loehr |first=Kaleena |date=July 8, 2010 |title=Sky glow burning out? |url=http://www.merrittnews.net/article/20100708/MERRITT0101/100709954/-1/MERRITT/sky-glow-burning-out |access-date=2023-12-30 |website=www.merrittnews.net |publisher=Merritt News}}</ref> The benefits of this technological change include "saving energy through better focused lights, preserving the environment by reducing excess light that may affect flora and fauna, reducing crime and increasing safety by more adequately illuminating areas, and reducing health risks."<ref name="merrittnews.net"/>

== Scotobiology ==
{{main|Scotobiology}}
Scotobiology is the study of the role darkness plays in living organisms. It shows that the interruption of darkness by light pollution creates drastic effects for most organisms, changing their food gathering and feeding habits, their mating and reproduction behavior, or their migration behavior (in birds and insects) and social behavior.<ref name="sampaa.org">{{cite web |title=Light Pollution – conference proceedings |url=http://www.sampaa.org/publications/conference-proceedings-1991-2000/sampaa-6-proceedings/light-pollution/Bidwell%202010.pdf |url-status=dead |archive-url=https://web.archive.org/web/20211011002027/http://www.sampaa.org/publications/conference-proceedings-1991-2000/sampaa-6-proceedings/light-pollution/Bidwell%202010.pdf |archive-date=11 October 2021 |access-date=22 May 2022 |website=www.sampaa.org}}</ref> Approximately 30% of vertebrates and 60% of invertebrates are nocturnal, meaning that they depend on darkness. Their everyday behaviors are biologically evolved to adapt in uninterrupted darkness.<ref>Scott R. Parker, S. L. (2011). Dark Skies, Bright Minds. Sources of Knowledge Forum, Ontario, Canada, pp. 12–17.</ref>

Human health is also adversely affected by the effects of light pollution. Light during nighttime hours has been linked to human cancers and psychological disorders.<ref name="sampaa.org"/>

== Dark-sky preserves ==
{{main|Dark-sky preserve}}
Dark-sky preserves are the main contributors to the dark-sky movement. They are protected areas found mostly in national parks that have a zero light pollution policy set in by the government and, in the US, controlled by the National Dark Sky Association.

As of February 6, 2012, there were 35 formally recognized dark-sky preserves in the world with Canada in the lead containing 15 preserves. These preserves are located in Nova Scotia, New Brunswick, Quebec, Ontario, Saskatchewan, Alberta, and British Columbia. Other countries that have dark-sky preserves are the Czech Republic, Hungary, Poland, Slovakia, Spain, United Kingdom, and the United States. A list of designated parks is maintained by the Dark Skies Advisory Group <ref>http://www.darkskyparks.org/index.php?option=com_content&view=article&id=564 Dark Skies Advisory Group</ref> of the International Union for Conservation of Nature (IUCN).

The parks are put in place by the Dark Sky Places program with the intention to remind us that the night sky serves just as much importance to our culture and history as our day-time sky.<ref>http://www.darksky.org/index.php?option=com_content&view=article&id=564 International Dark Sky Association: "International Dark Sky Places</ref>

== International Dark-Sky Association ==
{{main|International Dark-Sky Association}}
The International Dark-Sky Association (IDA) began in 1988. A non-profit, it manages the Fixture Seal of Approval program, which offers a third-party rating system judging the "sky-friendliness" of lighting fixtures. Another prominent outreach effort is the IDA [https://darksky.org/what-we-do/international-dark-sky-places/ Dark Sky Places] program, created after a proposal from the [https://flagstaffdarkskies.org/ Flagstaff Dark Skies Coalition] in 2001 and the recognition of Flagstaff as the [https://darksky.org/places/flagstaff-arizona-dark-sky-community/ First International Dark-Sky Community] in October 2001. IDA now recognizes over 200 Dark Sky Places worldwide. In 2009, the IDA opened an office for public policy and government affairs in [[Washington, D.C.]] to inform lawmakers and lobbyists about the energy efficiency of outdoor lighting and to promote the adoption of energy-saving measures.<ref>http://www.darksky.org/about-ida International Dark Sky association: "About the IDA"</ref> The IDA advances dark sky awareness and protection through promotion of guidelines developed in collaboration with lighting industry partners (e.g. [[IESNA]]).{{Cn|date=October 2024}} The recently published (2020) [https://darksky.org/resources/guides-and-how-tos/lighting-principles/ Five Principles of Responsible Outdoor Lighting], are:

* Useful: Use light only if it is needed
* Targeted: Direct light so it falls only where it is needed
* Low Level: Light should be no brighter than necessary
* Control: Use light only when it is needed
* Warm -colored: Use warmer color lights where possible

== List of groups ==
{{Div col}}
*[http://www.anpcen.fr ANPCEN] (France)
*[[Astronomitaly]] (Italy)
*[[Campaign for Dark Skies]] (UK)
*[[Canadian Geographic]] (Canada)
*[[Canadian Scotobiology Group]] (Canada)
*[[CieloBuio]] (Italy)
*[https://flagstaffdarkskies.org Flagstaff Dark Skies Coalition]
*[[International Dark-Sky Association]]
*[[National Dark-Sky Week]] (United States)
*[[Niue]]
*[[Royal Astronomical Society of Canada]] (Canada)
{{End div col}}

== See also ==
{{Div col}}
*[[Bortle dark-sky scale]]
*[[SKYGLOW]]
*[[Dark-sky preserve]]
*[[Noctcaelador]]
*[[Dark infrastructure]]
{{End div col}}

== References ==
{{Reflist|30em}}

== External links ==
*[http://www.darksky.org/ International Dark-Sky Association]
*[https://web.archive.org/web/20110718102049/https://www.mydarksky.com/ MyDarkSky – dark sky survey maps]
*[http://bbs.keyhole.com/ubb/showthreaded.php/Cat/0/Number/587221/an/0/page/0#587221/ Outdoor Lighting Regulations and Ordinances on Google Earth] {{Webarchive|url=https://web.archive.org/web/20070930032922/http://bbs.keyhole.com/ubb/showthreaded.php/Cat/0/Number/587221/an/0/page/0#587221/ |date=2007-09-30 }}
*[http://www.lawserver.com/dark-sky-laws Interactive map comparing U.S. dark sky laws]
*[https://web.archive.org/web/20111028172132/http://buzzlog.yahoo.com/buzzlog/94259 The dark sky movement – yahoo]
*[http://www.canadiangeographic.ca/magazine/apr11/astronomy_jasper_national_park.asp Jasper National Park] {{Webarchive|url=https://web.archive.org/web/20120512033127/http://canadiangeographic.ca/magazine/apr11/astronomy_jasper_national_park.asp |date=2012-05-12 }}
*[http://www.darkskyparks.org/dsag/DSP%20world%20list_feb2012.pdf Dark-sky parks of the world]{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}
*[http://www.flagstaffdarkskies.org/ Flagstaff Dark Skies Coalition]
*[https://www.globeatnight.org/ Globe at Night]
*[http://citiesatnight.org/ Cities at Night]
*[http://www.darkskiesawareness.org/ Dark Skies Awareness] {{Webarchive|url=https://web.archive.org/web/20110410132211/http://www.darkskiesawareness.org/ |date=2011-04-10 }}
*[http://darkskystudies.org/ The Consortium for Dark Sky Studies]

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[[Category:Environmental movements]]
[[Category:Light pollution]]