A dark-sky preserve (DSP) is an area, usually surrounding a park or observatory , that restricts or reduces light pollution or maintains and protects naturally dark night skies. Different terms have been used to describe these areas as national organizations and governments have worked independently to create programs. DarkSky International (DarkSky) uses "International Dark Sky Reserve" (IDSR) and "International Dark Sky Park" (IDSP) among others when certifying Dark Sky Places.
59-573: The Central Idaho Dark Sky Reserve is a 1,416-square-mile (3,670 km) dark-sky preserve near the Sawtooth National Recreation Area , in the U.S. state of Idaho . It was designated on December 18, 2017, and is the first gold-tier dark sky preserve in the United States. The area was designated by International Dark-Sky Association . The area includes the city of Ketchum, Idaho which was separately designated
118-466: A "Dark Sky Community" in 2017. Idaho State Highway 75 in the Sawtooth Valley between Redfish Lake and Pettit Lake roughly traverses the reserve's "core areas". Several sky quality meters are installed along State Highway 75 in this area. Local communities and federal authorities collaborated in the designation; the governments will take measures such as shielding street lights to preserve
177-713: A dark-sky preserve is based on the sensitivity of wildlife to artificial light at night. Canada has established an extensive and stringent standard for dark-sky preserves, that addresses lighting within dark-sky preserves and influences from skyglow from urban areas in the region. This was based on the work of the Royal Astronomical Society of Canada . DarkSky International's Dark Sky Places program currently offers five types of designations: Dark Sky Developments of Distinction recognize subdivisions, master planned communities, and unincorporated neighborhoods and townships whose planning actively promotes
236-584: A mechanism for processing citizen inquiries and complaints. The U.S. Green Building Council (USGBC) has also incorporated a credit for reducing the amount of light trespass and sky glow into their environmentally friendly building standard known as LEED . Light trespass can be reduced by selecting light fixtures that limit the amount of light emitted more than 80° above the nadir. The IESNA definitions include full cutoff (0%), cutoff (10%), and semi-cutoff (20%). (These definitions also include limits on light emitted above 90° to reduce sky glow.) Over-illumination
295-567: A meeting in 2009 on Circadian Disruption and Cancer. In different wavelengths of light, red light has the least inhibitory effect on melatonin. In June 2009, the American Medical Association developed a policy in support of control of light pollution. News about the decision emphasized glare as a public health hazard leading to unsafe driving conditions. Especially in the elderly, glare produces loss of contrast, obscuring night vision. A new 2021 study published in
354-856: A more natural night sky but does not qualify them for the International Dark Sky Community designation. This designation was retired in 2020. Further designations include "Dark Sky Nation", given to the Kaibab Indian Reservation , and "Parashant International Night Sky Province-Window to the Cosmos", given to Grand Canyon-Parashant National Monument . As of January 2023, there are 201 certified Dark Sky Places globally: 38 Communities, 115 Parks, 20 Reserves, 16 Sanctuaries, 6 Developments of Distinction and 6 Urban Night Sky Places. Walnut Canyon National Monument / Wupatki National Monument Some regions, like
413-446: Is a hormone that regulates photoperiodic physiology and behaviour. Some species of frogs and salamanders utilize a light-dependent "compass" to orient their migratory behaviour to breeding sites. Introduced light can also cause developmental irregularities, such as retinal damage, reduced juvenile growth, premature metamorphosis, reduced sperm production, and genetic mutation. Close to global coastal megacities (e.g. Tokyo, Shanghai),
472-528: Is a nine-level measuring system used to track how much light pollution there is in the sky. A Bortle scale of four or less is required to see the Milky Way whilst one is "pristine", the darkest possible. Inspection of the area surrounding Madrid reveals that the effects of light pollution caused by a single large conglomeration can be felt up to 100 km (62 mi) away from the center. Global effects of light pollution are also made obvious. Research in
531-418: Is a public-health hazard—especially the older you become. Glare light scattering in the eye causes loss of contrast and leads to unsafe driving conditions, much like the glare on a dirty windshield from low-angle sunlight or the high beams from an oncoming car." In essence bright and/or badly shielded lights around roads can partially blind drivers or pedestrians and contribute to accidents. The blinding effect
590-592: Is also used to refer to artificial light indoors. 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. Light pollution is a side-effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, outdoor area lighting (such as car parks), offices, factories, streetlights, and illuminated sporting venues. It
649-449: Is caused by inefficient or unnecessary use of artificial light. Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, and skyglow. A single offending light source often falls into more than one of these categories. Solutions to light pollution are often easy steps like adjusting light fixtures or using more appropriate light bulbs. Further remediation can be done with more efforts to educate
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#1732791605095708-417: Is caused in large part by reduced contrast due to light scattering in the eye by excessive brightness, or to the reflection of light from dark areas in the field of vision, with luminance similar to the background luminance. This kind of glare is a particular instance of disability glare, called veiling glare. (This is not the same as loss of accommodation of night vision which is caused by the direct effect of
767-536: Is clear that preserving natural darkness has positive effects on the health of nocturnal wildlife within the parks. For example, the nocturnal black-footed ferret was reintroduced to the Grasslands National Park dark-sky preserve and the success of the reintroduction is enhanced by the pristine natural darkness maintained within the park by the DSP agreement. Light pollution Light pollution
826-475: Is most severe in highly industrialized, densely populated areas of North America, Europe, and Asia and in major cities in the Middle East and North Africa like Tehran and Cairo , but even relatively small amounts of light can be noticed and create problems. Awareness of the harmful effects of light pollution began in the second half of the 19th century, but efforts to address its effects did not begin until
885-400: Is natural. To precisely measure how bright the sky gets, night time satellite imagery of the earth is used as raw input for the number and intensity of light sources. These are put into a physical model of scattering due to air molecules and aerosoles to calculate cumulative sky brightness. Maps that show the enhanced sky brightness have been prepared for the entire world. The Bortle scale
944-519: Is no replacement pollinator that would not be affected by the artificial light. This can lead to species decline of plants that are unable to reproduce, and change an area's longterm ecology . Among nocturnal insects, fireflies ( Coleoptera : Lampyridae, Phengodidae and Elateridae) are especially interesting study objects for light pollution, once they depend on their own light to reproduce and, consequently, are very sensitive to environmental levels of light. Fireflies are well known and interesting to
1003-574: Is not excessive in all developed countries. Amongst developed countries there are large variations in patterns of light use. American cities emit three to five times more light to space per capita compared to German cities. Over-illumination stems from several factors: Most of these issues can be readily corrected with available, inexpensive technology , and with the resolution of landlord/tenant practices that create barriers to rapid correction of these matters. Most importantly, public awareness would need to improve for industrialized countries to realize
1062-539: Is orchestrated by the natural diurnal patterns of light and dark, so disruption to these patterns impacts the ecological dynamics. Many species of marine plankton, such as Calanus copepods, can detect light levels as low as 0.1 μWm ; using this as a threshold a global atlas of marine Artificial Light at Night has been generated, showing its global widespread nature. Studies suggest that light pollution around lakes prevents zooplankton, such as Daphnia , from eating surface algae , causing algal blooms that can kill off
1121-534: Is the excessive and unnecessary use of light. A large and overabundant amount of electricity is required to support light consumption in the United States. U.S homes consumed 81 billion kilowatthours (kWh) of electricity for lighting in 2020 according to the U.S. Energy Information Administration's (EIA). Additionally, the EIA reported that 208 billion kWh and 53 billion kWh of electricity were used for commercial and manufacturing buildings respectively in 2018. Light use
1180-488: Is the presence of any unwanted, inappropriate, or excessive artificial lighting . In a descriptive sense, the term light pollution refers to the effects of any poorly implemented lighting sources, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind of pollution, but also as a contributor to the wider, collective impact of various sources of pollution. Although this type of pollution can exist throughout
1239-479: The IAU , fear that light pollution will increase significantly, one of many concerns reported in the media regarding satellite overcrowding. Public discourse surrounding the continuing deployment of satellite constellations includes multiple petitions by astronomers and citizen scientists, and has raised questions about which regulatory bodies hold jurisdiction over human actions that obscure starlight. Measuring
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#17327916050951298-503: The International Dark-Sky Association has developed a set of model lighting ordinances. The Dark-Sky Association was started to reduce the light going up into the sky which reduces the visibility of stars (see Skyglow below). This is any light that is emitted more than 90° above nadir . By limiting light at this 90° mark they have also reduced the light output in the 80–90° range which creates most of
1357-457: The Milky Way galaxy. Light trespass occurs when unwanted light enters one's property, for instance, by shining over a neighbour's fence. A common light trespass problem occurs when a strong light enters the window of one's home from the outside , causing problems such as sleep deprivation . A number of cities in the U.S. have developed standards for outdoor lighting to protect the rights of their citizens against light trespass. To assist them,
1416-752: The Mont Mégantic Observatory in Quebec was the first site to be certified as an International Dark Sky Reserve by DarkSky. The same year, Natural Bridges National Monument in Utah became the first International Dark Sky Park. The Gabriela Mistral Dark Sky Sanctuary in the Elqui Valley of Chile was designated as the world's first International Dark Sky Sanctuary in 2015. A dark-sky preserve, or dark-sky reserve, should be sufficiently dark to promote astronomy . The lighting protocol for
1475-493: The Solar cycle ) but given optimal conditions, the darkest possible sky has a brightness of about 22 magnitude/square arc second. If a full moon is present, the sky brightness increases to about 18 magnitude/sq. arcsecond depending on local atmospheric transparency, 40 times brighter than the darkest sky. In densely populated areas a sky brightness of 17 magnitude/sq. an arcsecond is not uncommon, or as much as 100 times brighter than
1534-404: The 1950s. In the 1980s a global dark-sky movement emerged with the founding of the International Dark-Sky Association (IDA). There are now such educational and advocacy organizations in many countries worldwide. About 83% of people, including 99% of Europeans and Americans, live under light-polluted skies that are more than 10% brighter than natural darkness. 80% of North Americans cannot see
1593-542: The CfDS handbook "Blinded by the Light?". Chapter 4, "Human health implications of light pollution" states that "... light intrusion, even if dim, is likely to have measurable effects on sleep disruption and melatonin suppression. Even if these effects are relatively small from night to night, continuous chronic circadian, sleep and hormonal disruption may have longer-term health risks". The New York Academy of Sciences hosted
1652-518: The Southern Economic Journal indicates that light pollution may increase by 13% in preterm births before 23 weeks of gestation. While light at night can be beneficial, neutral, or damaging for individual species , its presence invariably disturbs ecosystems. For example, some species of spiders avoid lit areas, while other species are happy to build their webs directly on lamp posts. Since lamp posts attract many flying insects,
1711-453: The U.S. Fish and Wildlife Service of the number of birds killed after being attracted to tall towers range from four to five million per year to an order of magnitude higher. The Fatal Light Awareness Program (FLAP) works with building owners in Toronto , Ontario , Canada and other cities to reduce mortality of birds by turning out lights during migration periods. Another study has found that
1770-526: The U.S. Sky quality in the U.S. ranges from pristine ( Capitol Reef National Park and Big Bend National Park ) to severely degraded ( Santa Monica Mountains National Recreation Area and Biscayne National Park ). The National Park Service Night Sky Program monitoring database is available online (2015). Light pollution in Hong Kong was declared the 'worst on the planet' in March 2013. In June 2016, it
1829-440: The area's dark sky; Ketchum has had a dark sky ordinance since 1999, and Sun Valley , also in the reserve, has its own local ordinance. The U.S. Forest Service , which manages much of the land in the area, will post informational signs about the dark sky reserve, and has said it will reduce light pollution from its buildings; compliance by individuals on Forest Service land will be voluntary. Another dark sky certification effort
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1888-428: The atmosphere The effect of sky glow can be harmful in astronomy and on the health of many organisms. It worsens the visibility of the stars, the Milky Way , and significantly increases the natural light levels at night. Also contributing to light pollution are artificial satellites . With increasing numbers of satellite constellations such as OneWeb and Starlink , members of the astronomical community, notably
1947-705: The blue band. In North America the situation is comparable. There is a significant problem with light pollution ranging from the Canadian Maritime Provinces to the American Southwest. The International Dark-Sky Association works to designate areas that have high-quality night skies. These areas are supported by communities and organizations that are dedicated to reducing light pollution (e.g. Dark-sky preserve ). The National Park Service Natural Sounds and Night Skies Division has measured night sky quality in national park units across
2006-406: The day, because direction of natural polarization of sun light and its reflection is a source of information for a lot of animals). This form of pollution is named polarized light pollution (PLP). Unnatural polarized light sources can trigger maladaptive behaviors in polarization-sensitive taxa and alter ecological interactions. Lights on tall structures can disorient migrating birds. Estimates by
2065-606: The day, its effects are magnified during the night with the contrast of the sky's darkness. It has been estimated that 83 percent of the world's people live under light-polluted skies and that 23 percent of the world's land area is affected by skyglow . The area affected by artificial illumination continues to increase. A major side effect of urbanization , light pollution is blamed for compromising health, disrupting ecosystems, and spoiling aesthetic environments. Studies show that urban areas are more at risk. Globally, it has increased by at least 49% from 1992 to 2017. Light pollution
2124-560: The development and trial of new lighting technologies in the North Sea. In early 2007, the lights were installed on the Shell production platform L15. The experiment proved a great success since the number of birds circling the platform declined by 50 to 90%. Birds migrate at night for several reasons. Save water from dehydration in hot day flying and part of the bird's navigation system works with stars in some way. With city light outshining
2183-598: The direct lighting effect by adding softening filters or other solutions, though intensity will be reduced. Glare can be categorized into different types. One such classification is described in a book by Bob Mizon, coordinator for the British Astronomical Association's Campaign for Dark Skies, as follows: According to Mario Motta, president of the Massachusetts Medical Society , "... glare from bad lighting
2242-467: The effect of sky glow on a global scale is a complex procedure. The natural atmosphere is not completely dark, even in the absence of terrestrial sources of light and illumination from the Moon. This is caused by two main sources: airglow and scattered light . At high altitudes, primarily above the mesosphere , there is enough UV radiation from the sun at very short wavelengths to cause ionization . When
2301-526: The following, are protected without any reference to an observatory or a park. In the Canadian program, lighting within the area must be strictly controlled to minimize the impact of artificial lighting on wildlife. These guidelines are more stringent than in other countries that lack the extensive wilderness areas that still exist in Canada. The management of a Canadian DSP extends their outreach programs from
2360-521: The general public (unlike many other insects) and are easily spotted by non-experts, and, due to their sensibility and rapid response to environmental changes, good bioindicators for artificial night lighting. Significant declines in some insect populations have been suggested as being at least partially mediated by artificial lights at night. A 2009 study also suggests deleterious impacts on animals and ecosystems because of perturbation of polarized light or artificial polarization of light (even during
2419-407: The higher layers and thus no appreciable ionization occurs. 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. The amount of airglow and zodiacal light is quite varied (depending, amongst other things on sunspot activity and
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2478-563: The highest levels of ALAN reported the highest number of cases of breast cancer. Seoul, which had the highest levels of light pollution, had 34.4% more cases of breast cancer than Ganwon-do, which had the lowest levels of light pollution. This suggested a high correlation between ALAN and the prevalence of breast cancer. It was also found that there was no correlation between other types of cancer such as cervical or lung cancer and ALAN levels. A more recent discussion (2009), written by Professor Steven Lockley, Harvard Medical School, can be found in
2537-992: The human body suggests that a variety of adverse health effects may be caused by light pollution or excessive light exposure, and some lighting design textbooks use human health as an explicit criterion for proper interior lighting. Health effects of over-illumination or improper spectral composition of light may include: increased headache incidence, worker fatigue , medically defined stress , decrease in sexual function and increase in anxiety. Likewise, animal models have been studied demonstrating unavoidable light to produce adverse effect on mood and anxiety. For those who need to be awake at night, light at night also has an acute effect on alertness and mood. Outdoor artificial light at night – exposure to contemporary types such as current types of street lighting – has been linked to risks for obesity, mental disorders, diabetes , and potentially other health issues by preliminary studies. In 2007, "shift work that involves circadian disruption"
2596-476: The ions collide with electrically neutral particles they recombine and emit photons in the process, causing airglow . The degree of ionization is sufficiently large to allow a constant emission of radiation even during the night when the upper atmosphere is in the Earth's shadow. Lower in the atmosphere all the solar photons with energies above the ionization potential of N 2 and O 2 have already been absorbed by
2655-424: The lakes' plants and lower water quality. Light pollution may also affect ecosystems in other ways. For example, entomologists have documented that nighttime light may interfere with the ability of moths and other nocturnal insects to navigate. It can also negative impact on insect development and reproduction. Night-blooming flowers that depend on moths for pollination may be affected by night lighting, as there
2714-424: The large payoff in reducing over-illumination. In certain cases, an over-illumination lighting technique may be needed. For example, indirect lighting is often used to obtain a "softer" look, since hard direct lighting is generally found less desirable for certain surfaces, such as skin. The indirect lighting method is perceived as cozier and suits bars, restaurants, and living quarters. It is also possible to block
2773-444: The late 1990s showed that the entire area consisting of southern England, Netherlands, Belgium, West Germany, and northern France have a sky brightness of at least two to four times normal. The only places in continental Europe where the sky can attain its natural darkness are in northern Scandinavia and in islands far from the continent. The growth of light pollution on the green band has been 11% from 2012–2013 to 2014–2020, and 24% on
2832-407: The light itself on the eye.) Light clutter refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles (including those that they may be intended to illuminate), and potentially cause accidents. Clutter is particularly noticeable on roads where the street lights are badly designed, or where brightly lit advertisements surround the roadways. Depending on
2891-546: The light trespass issues. U.S. federal agencies may also enforce standards and process complaints within their areas of jurisdiction. For instance, in the case of light trespass by white strobe lighting from communication towers in excess of FAA minimum lighting requirements the Federal Communications Commission maintains an Antenna Structure Registration database information which citizens may use to identify offending structures and provides
2950-462: The lights produced by the Post Tower has affected 25 bird species. As a result, they discovered that decreasing the use of excessive lights increased the survival rate of bird species. Similar disorientation has also been noted for bird species migrating close to offshore production and drilling facilities. Studies carried out by Nederlandse Aardolie Maatschappij b.v. (NAM) and Shell have led to
3009-431: The motives of the person or organization that installed the lights, their placement and design can even be intended to distract drivers, and can contribute to accidents. Sky glow is the bright haze above cities that is produced from excessive artificial lighting at night. This type of light pollution is created from artificial light reflecting in the sky and bouncing around the different types of particles that reside in
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#17327916050953068-521: The natural illumination cycles provided by the moon in the marine environment are considerably disrupted by light pollution, with only nights around the full moon providing greater radiances, and over a given month lunar dosages may be a factor of 6 less than light pollution dosages. In September 2009, the 9th European Dark-Sky Symposium in Armagh, Northern Ireland had a session on the environmental effects of light at night (LAN). It dealt with bats, turtles,
3127-802: The night sky, birds (and also about mammals) no longer navigate by stars. Sea turtle hatchlings emerging from nests on beaches are another casualty of light pollution. It is a common misconception that hatchling sea turtles are attracted to the moon. Rather, they find the ocean by moving away from the dark silhouette of dunes and their vegetation, a behavior with which artificial lights interfere. The breeding activity and reproductive phenology of toads, however, are cued by moonlight. Juvenile seabirds are also disoriented by lights as they leave their nests and fly out to sea, causing events of high mortality. Amphibians and reptiles are also affected by light pollution. Introduced light sources during normally dark periods can disrupt levels of melatonin production. Melatonin
3186-401: The public in order to push legislative change. However, because it is a man-made phenomenon, addressing its impacts on humans and the environment has political, social, and economic considerations. Light pollution is the presence of anthropogenic artificial light in otherwise dark conditions. The term is most commonly used in relation to in the outdoor environment and surrounding, but
3245-553: The public that visit the site to include the promotion of better lighting policies in surrounding urban areas. Currently, dark-sky preserves have more control over internal and external lighting than other programs. With the increase in regional light pollution , some observatories have actively worked with cities in their region to establish protection zones where there is controlled light pollution. These areas may not yet have been declared dark-sky preserves. Although dark-sky preserve designations are generally sought by astronomers, it
3304-508: The spiders that tolerate the light gain an advantage over the spiders that avoid it. This is a simple example of the way in which species frequencies and food webs can be disturbed by the introduction of light at night. Light pollution poses a serious threat in particular to nocturnal wildlife, having negative impacts on plant and animal physiology. It can confuse animal navigation , alter competitive interactions, change predator-prey relations, and cause physiological harm. The rhythm of life
3363-485: Was estimated that one third of the world's population could no longer see the Milky Way, including 80% of Americans and 60% of Europeans. Singapore was found to be the most light-polluted country in the world. Over the past 21 years, China's provincial capital cities have seen a major increase in light pollution, with hotspots along the eastern coastline region. Medical research on the effects of excessive light on
3422-584: Was listed as a probable carcinogen by the World Health Organization's International Agency for Research on Cancer. (IARC Press release No. 180). Multiple studies have documented a correlation between night shift work and the increased incidence of breast and prostate cancer. One study which examined the link between exposure to artificial light at night (ALAN) and levels of breast cancer in South Korea found that regions which had
3481-457: Was under way in 2017 about 80 miles (130 km) away at Bruneau Dunes State Park , which hosts a public astronomical observatory . Dark-sky preserve DarkSky International was founded in 1988 to reserve public or private land for an exquisite outlook of nocturnal territories and starry night skies. Dark-sky preserves are specifically conserved for their cultural, scientific, natural, or educational value and public enjoyment. In 2007,
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