Dark Sky Ordinances: Separating the Light from the Darkness

Dark Sky Ordinances: How to Separate the Light from the Darkness by David B. Kopel and Michael Loatman1 IP-4-2006 March 2006 Executive Summary In many areas of the United States it is difficult to view the stars in the sky at night. The International Dark Sky Association2, has successfully lobbied state and local governments to pass restrictive ordinances on the type of lighting private property owners may use. These “Dark Sky laws” aim to reduce “light pollution” so as to make stargazing easier. Many of these laws, such as the City of Aspen’s, impose unfairly short deadlines in forcing property owners to replace their current lighting. Excessively severe Dark Sky laws overlook the role that lighting plays in deterring crime. States and localities should consider some key facts when studying dark sky legislation: • Light is a good, not a form of pollution. Night-time lighting greatly expands human freedom of action. • Urban lighting in the United States is not harming advanced astronomical research. • Amateur astronomy is best conducted away from urban areas. • Dark sky ordinances mainly benefit casual urban stargazers. • Research shows that improved street lighting reduces crime by 20 percent. • Retroactive ordinances are extremely costly and unfair to private property owners. • There are many good Dark Skies laws which, imposed prospectively, can enhance stargazing without harming other interests. The final section of this Issue Paper provides some examples. Page 1  I. Lighting is a good, not a form of they have the right to do so. Only the most extreme pollution form of an oppressive Nanny State would try to control people’s bedtimes.3 Advocates of harshly restrictive Dark Sky laws have Only the most invented the phrase “light pollution,” a misleading There are, however, many moderate extreme form of term that should be banished from public discussion. and reasonable advocates of Dark an oppressive Dioxin is a true pollutant; it is a by-product of Skies legislation, and they make Nanny State certain industrial processes, and although the some very good points. Throughout would try to processes create useful goods, dioxin itself is of no human history people have studied control people’s value to any living creature. Dioxin is an unwanted, the heavens. To gaze at the moon and bedtimes. harmful, and useless waste product. stars and planets is to look beyond So the phrase “dioxin pollution” the earth and beyond oneself—and Advocates of makes sense. for a moment, to forget oneself and harshly restrictive thus to see everything else—to see the bigger picture Dark Sky laws When people talk about “air of the wondrous universe. have invented pollution” or “water pollution”, they the phrase “light are really talking about pollutants in If you learn at least a little astronomy, then you will pollution,” a mis- the air or water; they are not claiming have an easier time finding your way when you are leading term that that air or water are themselves a lost, because you can find the North Star. You will should be ban- form of pollution. know how to the tell the difference between the ished from public Winter Sky (featuring the clear, sharp light of Orion discussion. The term “light pollution” is the Hunter in the southern sky) and the Summer premised on the mistaken idea that Sky (featuring bright Vega and the Northern Cross light itself is a form of pollution, arcing across the top of the sky). On moonless rather than a positive good, like air and water. Light nights, you may see the Milky Way. For some helps reduce crime and has allowed people in the people, the quiet reflective times of stargazing help twenty-first century—unlike their ancestors from them find their way when they are lost in a non- darker ages—to continue reading, socializing, and geographic sense. A child or an adult who is always engaging in other activities after the sun goes down. inside watching television every evening is missing a Man-made light allows more human choices and much more important show outside in the sky. therefore more freedom. Enjoying the Night Sky is not difficult for a As scientists have noted, most man-made light beginner. Mercury, Venus, Mars, Jupiter, and Saturn does not reproduce the full spectrum of solar are all visible to the naked eye, as are dozens of light. It has been argued that people who get too constellations. No matter what the time of year, much indoor light, and not enough sunlight, suffer there are always a few very bright stars which are from disruption of their natural body rhythms, easy to find and identify. With binoculars, a person thus interfering with the production of melatonin can see moons of Jupiter, the rings of Saturn, the and of hormones, and possibly making themselves planets Uranus and Neptune, the closest galaxy more vulnerable to cancer. Thus, some of the more (Andromeda), and beautiful details on the surface extreme Dark Sky advocates, who want to drastically of Earth’s moon. curtail man-made lighting, claim that they are doing people a favor. We disagree. So the proponents of Dark Sky laws are exactly right in their desire to preserve the opportunity for Adults are capable of making their own decisions stargazing. However, the use of the phrase “light about bedtime. If they choose not to stay up late, pollution” is dead wrong. Light, after all, is what Page 2  the star-gazers want to see—either direct light from of Jupiter, and found that the Milky Way was made stars, or sunlight which is reflected off a planet or of stars. Today, a few hundred dollars can buy a moon. telescope much better than Galileo’s. Ten thousand dollars can purchase an outstanding computerized Sometimes man-made light may overwhelm telescope. But again, even the best of these amateur starlight, but this does not mean that man-made telescopes can only see objects almost all of which light is a pollutant simply because it is made by man, have already been carefully studied by professional whereas starlight or moonlight is astronomers.4 Sometimes good just because is not man-made. manmade light First of all, man is part of nature, and The telescopes used by Galileo and by modern may overwhelm therefore so is the light created by backyard astronomers are optical telescopes; starlight, but this man. Anti-light extremists who argue that is, they amplify light from visible spectrum. does not mean that man-made lighting is a pollutant It is the optical telescope which is most at risk that man-made because it is unnatural would—if of interference from man-made light is a pol- they were going to be consistent— terrestrial light. It is the optical lutant simply never use eyeglasses, binoculars, or telescope which because it is telescopes to stargaze. After all, eyes In the twentieth century, new is most at risk of made by man, are “natural” and telescopes are scientific telescopes were invented interference from whereas starlight artificial. which could receive and amplify manmade terres- or moonlight is waves from the non-optical portions trial light. good just because So as we consider how to facilitate of the electromagnetic spectrum. The is not manmade. the viewing of the lights of the most common such telescope is the heavens, let us not make the mistake radio telescope. Of course a radio telescope is not of considering the lights of the earth affected by street lights, but a radio telescope would to be “pollution.” Moonlight, starlight, and man- be hindered by interference from radio signals. made light are all good, and a sensible policy will seek to harmonize their public uses, rather than Today, professional scientists use extremely large imposing darkness for its own sake. and high-powered telescopes which they place in very isolated locations—as far as possible from II. Urban lights in the United States radio waves and street lights. The telescopes also are not affecting major astronomical are placed in elevated locations, to avoid distortions research. caused by the atmosphere.5 Among the most important locations for modern scientific telescopes Starting from the earliest times when humans are Mauna Kea, Hawaii; Mount Hopkins, Arizona; studied the stars, and continuing until a few hundred and Cerro La Silla, Chile.6 years ago, all scientific study of the stars was performed with the naked eye. Today, just about Given the costs of producing these large telescopes, all the naked eye research which can be done has research universities have to pool their resources been done; the only significant contribution which a to fund construction. The University of Colorado’s naked eye astronomer can make today is to report Center for Astrophysics and Space Astronomy has on the direction and number of meteors in his area joined the Astrophysical Research Consortium, during a meteor shower. which built the Apace Point Observatory in Sunspot, New Mexico.7 In 1609, Galileo invented the astronomical telescope. Within a few weeks, he discovered the mountains of the moon and the four largest moons Page 3  Accordingly, there are only a few remote locations subset of serious amateur astronomers. (Just as on earth where man-made light might interfere with there is a large number of casual coin collectors— the most advanced scientific research. There is no such as children who collect state quarters—and such location in Colorado. Only a few advanced a much smaller group of serious collectors of rare research telescopes are near cities, such as the Kitt coins.) High-quality modern amateur astronomical Peak telescope near Tucson, or the Mount Palomar equipment is about a hundred times more light- telescope near San Diego. sensitive than amateur equipment was several decades ago. So amateur astronomers have the Of course many universities in urban areas ability to see very low magnitude objects under good have their own observatories. The University of viewing conditions. Colorado at Boulder and Denver University have on-campus observatories; both are often opened Serious amateur astronomer organizations to the public for star-gazing events. The college encourage their members to observe away from observatories have powerful telescopes, but those urban areas. StarDate Online, which is produced telescopes are far less powerful than the advanced by the University of Texas McDonald Observatory, research telescopes in remote locations. Obviously suggests stargazing “in remote rural areas, far from the presence of urban light somewhat reduces the lights of cities and towns.” They also note that the capabilities of the college campus telescopes. high altitude helps the view and therefore suggests Indeed, if the cities of Denver and Boulder viewing on top of a hill to avoid the turbulence of vanished, the light which is emitted just from Earth’s atmosphere.8 the DU and CU campuses would be considered intolerable if the light were near one of the Instead of conducting stargazing sessions in advanced research telescopes in Arizona or Hawaii. suburbia or the cities, amateur astronomy groups often travel out to remote areas. For example, However, a college which chooses to build a the Western Colorado Astronomy Club conducts telescope on-campus is making a conscious viewing sessions on top of Blue Mesa, on the Rabbit trade-off. By being on campus, the telescope will Valley Overlook, and the Colorado necessarily be near man-made light; if the campus National Monument.9 The Denver Other than by is located in an urban area, there will Astronomical Society conducts “star returning to the be even more man-made light. On parties” in a location near Byers. Dark Ages, it ...a college which the other hand, the urban college would be impos- chooses to build telescope is located conveniently to Other than by returning to the Dark sible for any city a telescope on- students, faculty, and people who Ages, it would be impossible for any to come close campus is mak- live in the college town. Thus, the city to come close to matching the to matching the ing a conscious collegiate telescope can be used to extremely low levels of man-made extremely low lev- trade-off. educate many people. light which are found at amateur els of man-made astronomy observation sessions. At light which are star parties, cars are required to turn found at amateur III. Serious amateur astronomy is off their headlights. (Indeed, cars are astronomy obser- best conducted away from urban one of the very major light sources vation sessions. and residential areas in cities, and there is no current practical way to reduce headlight As we have discussed above, almost anyone can illumination without causing many more accidents.) be at least a casual astronomer, and we wish that Even ordinary flashlights are disfavored at star almost everyone would. Among the people who parties; participants instead use small flashlights know their way around the Night Sky, there is a which emit low levels of red light. Page 4  IV. Dark Sky laws benefit mainly B. Dark Sky laws should not interfere with solitary, casual, residential lifestyle choices stargazing We favor reasonable Dark Sky ordinances because we want to encourage backyard astronomy. But we The main beneficiaries of dark sky ordinances are do not favor oppressive ordinances people who wish to view the night sky from their which violate the rights of other Simply because backyard. Anyone who does not study the Night Sky people. Simply because we believe (as we believe (as at least occasionally is missing an important part of does the Dark Sky Association) that does the Dark the human experience. stargazing is an especially important Sky Association) activity does not mean that we have that stargazing A. All choices of a residence involve the right to injure other people who is an especially voluntary trade-offs do not feel the same the way. In important activ- People always make trade-offs in their lives, and particular, we have no right to harm ity does not mean some trade-offs involve sacrificing one good in them financially, and no right to put that we have the favor of other goods. If you choose them in danger of being attacked by right to injure ...when you move to live in Hawaii, you will enjoy the a violent criminal. And we certainly other people who to Manhattan, abundant sunshine and water, but have no right to try to limit their do not feel the you should not you should not complain that you nighttime lighting because a scientist same the way. complain that cannot go ice-climbing. Similarly, theorizes that people’s natural you cannot afford if you choose to live in Manhattan, circadian rhythms would be better a large house you can enjoy the ballet, the opera, served by going to bed at sunset.10 with a half-acre the museums, the bookstores, the yard, and you street scenes, and the millions of C. Very dark skies are not necessary to also should not other special activities possible when encourage beginning astronomers complain that it millions of people live together in a The brightness of a star is called the “magnitude.” is hard to see the compact area. But when you move to A star with a magnitude of 1 is 2.51 times brighter Orion Nebula Manhattan, you should not complain than a star with a magnitude of 2. A star with a distinctly. that you cannot afford a large house magnitude of 2 is 2.51 times brighter than a star with with a half-acre yard, and you also a magnitude of 3. And so on. The limit of naked-eye should not complain that it is hard to visibility is about magnitude 5.5 or 6. see the Orion Nebula distinctly. On a clear, moonless night on a mountain top in the We point out these obvious trade-offs because countryside, when the atmosphere is perfectly still, some Dark Sky advocates refuse to acknowledge a person with perfect vision can see about 2,500 or them. There are Dark Sky advocates who complain 3,000 stars. (A person in the southern hemisphere about the Las Vegas Strip. To state the obvious, would see an equal number of different stars.) the Las Vegas Strip is no place for people who Under excellent but not perfect conditions (a clear want to commune with nature. Just as a minority night in the countryside at sea level) a person would of people who eat organic food want to eliminate see about 1,500 stars. the “bad” choices of people who choose to eat highly processed food, some Dark Sky advocates If a site’s “limiting magnitude” is 5.5, there are seem determined to impose their low-light agenda about 800 visible stars. If the limiting magnitude is everywhere—regardless of the interests and needs of 5.0, about 400 stars would be visible. other humans. Galileo’s telescope enabled him to see about 30,000 stars. (Since the telescope allowed observation of Page 5 stars with magnitudes below the limits of naked eye see magnitude 11 stars in his telescope because of visibility.) Using all of the world’s best telescopes ambient urban light), then Dark Sky laws should today, there about 70 sextillion (70,000,000,000,000, focus mainly on preserving the night-time view of 000,000,000) observable stars. several hundred stars, rather than worrying about the visibility of magnitude 5.5 stars, which are a But to the extent that Dark Sky laws are primarily hindrance to the novice astronomer. intended to nurture a child’s sense of wonder in looking at the sky, the relevant form of observation V. Examples of Stargazing under is naked-eye observation. Varying Conditions For some types of naked-eye observation, darker is This section shows various views of the night sky, to better, and pitch black is best of all. For example, illustrate how different conditions affect the number even in a remote rural area, moonlight often of visible stars. Colors in the illustrative figures are washes out the Milky Way; so the Milky Way is best reversed, so that stars are dark, and the background observed on a moonless night. The Milky Way is a sky is light. beautiful and inspiring sight. It also is a beautiful experience to go into the countryside and observe the canopy of 1,500-3,000 visible stars. One of the things that make the viewing so beautiful is that the view is overwhelming. Under optimal conditions, the sky appears quite dense with stars. Every child should see and appreciate this awesome view. However, for the beginning or young astronomer, perfectly black conditions are not optimal. If one Figure 1. View from near Denver, on October is going to learn the night sky, then one needs to 6, 2005, looking at the Zenith (straight up). The learn to “navigate” the sky—to learn at least several field of vision is 90 degrees wide. Stars of up to constellations, and to be able to follow them as 5.5 magnitude are visible. Stars are represented they cross the sky during the night. As one learns as dots. Other objects (such as the Andromeda the constellations, one learns their seasonal cycles: Galaxy, or nebulae) have different shapes. The Orion comes out the Winter, the Northern Cross in Greek letters designate the major stars in each the summer, and the Big Dipper is out year-round, constellation. A view of the Zenith is generally but changes position throughout the year.11 superior to other views, because starlight travels through less of the Earth’s atmosphere. When one is learning the constellations, the 800 or Atmospheric fluctuations are what causes stars 3,000-star night sky can be overwhelming. There are to appear to twinkle. The pictures in this section simply too many stars for most beginners to be able presume that the atmosphere is perfectly still. to sort out the constellations easily. Pristine viewing conditions can be an impediment. The IDA’s main justification for restrictions on night-time lighting is “for the children.” If Dark Sky laws are really “for the children” (rather than for the dedicated hobbyist who is upset that he cannot Page 6 Figure 2. Same view. Stars of up to 4.5 magnitude. Figure 5. Same view. Stars up to 8.0 magnitude, Fewer stars visible, due to moonlight, man-made which are visible with high-quality astronomical light, or atmospheric turbulence. binoculars. Because a binoculars’ field of vision is relatively narrow, a person could only see a small slice of this view at any given moment. Figure 3. Same view. Only stars of 3.0 or brighter magnitude. Such a view could be the result of substantial interference from artificial light sources. Figure 6. One sixth (15 degrees wide) of the above view, showing stars up to magnitude 10, which are visible with a fairly expensive amateur telescope. A person using a telescope would not actually see such a view, because a telescope has a very narrow field of vision, approximately one degree. With the telescope, many areas of the sky would appear completely blank. Typically, an amateur astronomer with a powerful telescope would examine a single star (or perhaps a double star) or other sky object. Figure 4. Same view. Stars up to 4.0 magnitude. Constellation lines included. The result of lesser interference from artificial light. Page 7 VI. Improved street lighting reduces of Justice updated the 1977 review; the 1997 review crime by 20% and enhances feelings noted that a 1994 study in Scotland found that of security relighting in a Glasgow neighborhood resulted in a short term “reduction in victimizations that varied As long as humans have been keeping records of from 32 to 68 percent” and that the overall crime crime, there has been more crime at night-time than rate dropped 14 percent.15 Another study conducted in the day-time. in 1994 found that lighting improvements in three areas of London resulted in “Substantial reductions In an 1885 U.S. Supreme Court case, Justice Harlan in robberies, auto crimes, and threats” in two sites noted the importance of public street lighting for and the complete elimination of those crimes in public safety: the third site.16 However, the 1997 NIJ author discounted the London and Scottish studies because An English historian, contrasting the London they had not included a control area (a similar area of his day with the London of the time when where there was no change in lighting). Relying on its streets, supplied only with oil-lamps, were the 1977 DOJ article, the 1997 NIJ review restated scenes of nightly robberies, says that “the the old conclusions. adventurers in gas-lights did more for the prevention of crime than the government had B. Recent scholarship done since the days of Alfred.” 12 Research in the area of lighting and crime has continued since the summaries reported by the IDA. A. Older and inconclusive articles In 1999, criminologists David P. Farrington and The IDA claims that there is no relation between Brandon C. Welsh analyzed eight American studies increasing the amount of light and reducing and five British ones. They concluded that “the crime. The IDA points to two studies by the U.S. capacity of street lighting to influence crime has now Department of Justice and the National Institute been satisfactorily settled.”17 of Justice that supposedly did not find conclusive The Farrington- evidence of a link between improved lighting and The Farrington-Welsh analysis finds Welsh analysis crime reduction.13 The IDA’s claims are overstated: that “the overall reduction in crime finds that “the after improved lighting was 20% in overall reduction • The Department of Justice (DOJ) and the experimental areas compared with in crime after National Institute of Justice (NIJ) did not control areas.” 18 improved light- conduct studies, but instead reviewed already ing was 20% in existing studies. Farrington and Welsh explain that experimental • Neither the 1977 DOJ review nor the 1997 “Street lighting benefits the whole areas compared NIJ review denied that improved lighting may neighborhood rather than particular with control lower crime rates individuals or households...In short, areas.” • Many studies noted within these reviews did improved street lighting seems find a relationship between better lighting and to have no negative effects and reduced crime demonstrated benefits for law-abiding citizens.”19 • The National Institute of Justice “study” cited The National Crime Prevention Council also by IDA is merely a single page in a 469-page concludes that lighting has a crime deterrent effect book on a wide variety of crime reduction and increases detection of crime.20 techniques. The 1977 Department of Justice project reviewed Thus, street lighting is an especially beneficial form sixty studies of lighting and crime and found no of crime prevention. Burglar alarms, for example, conclusive pattern.14 In 1997 the National Institute do reduce burglary of homes with installed alarms, Page 8  but do not reduce the overall burglary rate in a back yard. It is also wonderful to be able to walk neighborhood.21 Burglar alarms impose a substantial down the street without being attacked by a violent burden on the community, because the vast majority predator. Sensible, moderate laws about Dark Skies of alarms are false alarms, which waste police can help casual astronomers without endangering resources.22 the public. The recent Farrington-Welsh article clearly VII. Some Dark Sky laws are supersedes the older, agnostic reports by the DOJ extremely costly and unfair to and the NIJ. Farrington and Welsh use more recent private property owners research. Unlike some of the studies which were discounted by the NIJ, the Farrington-Welsh analysis Dark sky ordinances can impose a substantial cost did use control areas. on landowners, business owners, and city and state governments. Consider, for example, a proposed In the world of public policy, a twenty percent ordinance in Durango, Colorado. reduction in crime is enormous. There are hardly A local businessman who runs four Dark sky ordi- any crime-reduction strategies for which even the Exxon stations calculated that the nances can most optimistic advocates can point to research cost of complying with the ordinance impose a sub- showing a twenty percent reduction. would be $50,000—an enormous stantial cost on expense for a small businessman.23 landowners, C. Enhanced feelings of safety The cost of fixing one middle school business owners, Not even the most fervent Dark Sky advocates deny in Durango was estimated to be and city and state that the public feels safer when there is sufficient $20,000—a huge capital cost for a governments. street lighting. Even the older research cited by typical public school.24 Dark Sky laws IDA concluded the public feels safer with sufficient should consider the cost to residents lighting. and businesses. Lighting in public areas encourages people to A. Prospective laws come out at night. Many local communities Laws which require businesses and homes to retrofit and universities light up common walkways so existing lights are unfair. If a property owner has as to create more inviting, safer-feeling spaces. installed lights in compliance with all existing zoning Vulnerable people are especially comfortable in and other laws, it is wrong for the government to lighted areas. suddenly force her to spend thousands of dollars because the government decides it prefers a new Now, the Farrington-Welsh research has confirmed form of lighting. the common sense of the public. The reason the public feels safer when lighting conditions are good A better approach can be found in the 2001 is because the public is safer. State of Colorado law which requires all outdoor ...when overly lighting fixtures funded by the state after July 1, restrictive Dark Thus, when overly restrictive Dark 2002, to meet listed requirements.25 This forward- Sky laws degrade Sky laws degrade the quality of street looking legislation is the best solution. Prospective the quality of lighting, they promote violent crime. legislation stops the problem from becoming worse, street lighting, Less street lighting means more since new lighting will be installed to meet the new they promote vio- rapes, more assaults, more robberies, standards. Property owners are not forced to tear lent crime. and more murders. out existing lights. It is wonderful to be able to see the details of the Crab Nebula from your Over time, most lighting fixtures are replaced. So Page 9  a prospective law ensures that eventually almost C. Aspen’s awful ordinance all the lights in a jurisdiction will meet the new Section 26.575.150 of the Code of the City of standards. A prospective Dark Skies law follows Aspen required that all light sources conform the same policy as that of the Americans with within one year of passage. Disabilities Act. Existing businesses were not This extremely short Section suddenly required to install elevators or other compliance period was very 26.575.150 of the accessibility improvements; however, high standards harsh on property owners, Code of the City of accessibility were imposed on new construction because it mandated that of Aspen required and on major renovations. lighting fixtures be replaced that all light long before the ordinary sources conform B. Boulder’s retroactive ordinance replacement cycle. within one year In Boulder, the city’s Dark Skies ordinance requires of passage. that current lighting fixtures be modified to Boulder is hardly known as meeting the revised standards within fifteen years.26 a town in which property The compliance period is relatively long, but any rights are of much concern to the local government. requirement for retrofitting is unfair. Doubtless, Yet even in the town nicknamed “the People’s many big businesses will buy new lights anyway in Republic,” property owners were given a fifteen year the next fifteen years; but some small businesses window. may be forced to spend thousands and thousands of dollars to replace construction which they installed Moreover, some of the asserted rationales for in full compliance with Boulder’s already arcane and Aspen’s oppressive ordinance were ridiculous. For rigorous zoning laws. example, the ordinance asserted the legislative purpose of “eliminating the escalation of night-time If Dark Skies, If darkening the skies of Boulder light pollution.” Eliminating the “escalation” of are, like public (or some other city) is really so night-time light “pollution” could be accomplished parks, a public important that existing lighting solely by imposing new standards prospectively on good, then the fixtures should be ripped out and future light fixtures—rather than by retroactively public should replaced, the proper approach would requiring replacement of existing light fixtures. pay for them. It be for the city to pay compensation would be wrong to property owners for the taking of The Aspen city council also asserted that the for a city gov- their property. If Dark Skies, are, ordinance would prevent the loss of “small town ernment to take like public parks, a public good, then character.”28 One might think that Aspen’s “small someone’s land the public should pay for them. It town character” is already preserved by zoning laws without compen- would be wrong for a city government which make additional density and expansion nearly sation in order to to take someone’s land without impossible. create a park for compensation in order to create a the public. park for the public. Likewise, it is Moreover, it is absurd to contend that “small-town wrong for a government to require a character” really depends on the kind of stargazing person to eliminate his lawful lighting distinctions which are preserved by the Aspen property, with no compensation, in order to create ordinance. The North Star (Polaris) is the last star Dark Skies for the public. 27 on the handle of the Little Dipper constellation. The constellation consists of three stars in the handle, and four on the cup. Two of the stars in the cup have a nearby, dim star, and these dim stars are also part of the constellation. (The dim stars are magnitude 5.2 and 5.5.) Does Aspen’s small-town feel really Page 10  depend on whether one can see the “extra” stars in Another problem with the Aspen statute is its the Little Dipper? On whether Aspen’s night-time limitations on security lighting. Because research has sky consists of 600 stars or 900? shown that lighting can reduce crime, it is troubling that the statute imposes restrictions on how A sky with 900 stars looks nicer than a sky with 600, security lighting is used. If these restrictions lower but it hardly has much to do with small-town feel. the efficacy of security lighting, the restrictions Small towns above the Arctic Circle have nearly would contravene the ordinance’s primary goal to perpetual sunlight in the summer, but it would be “promote safety and security.” ludicrous to claim that those towns lose their small- town feel because no stars are visible. Thus, Aspen should consider focusing its enforcement power on lights installed after the If encouraging a small-town sense of community ordinance and should reduce regulations of security is the goal of the ordinance, then Aspen should lighting. organize community night sky viewings (“star parties”). Star Aspen’s retroactive ordinance is an unfair violation If encouraging a parties would encourage a sense of of property rights, which the Colorado Constitution small-town sense community and enhance a small town guarantees are the right of every person in of community is character by encouraging neighbors Colorado, no matter where she lives. Just as the the goal of the to stargaze together instead of alone Colorado legislature in 2004 enacted ordinance, then in their backyards. The communal remedial legislation to prevent some ...Aspen should Aspen should stargazing could take place in municipal abuses of the eminent consider focusing organize com- mountain parks near Aspen, and domain power, the legislature should its enforcement munity night sky be led by astronomy professors or consider legislation to preempt abuse power on lights viewings (“star experienced amateur astronomers. of property rights via municipal Dark installed after the parties”). Children could also be encouraged to Sky ordinances. When the ordinance ordinance and go to these areas with their families has the effect of facilitating major should reduce and see more distant and fascinating elements of the violent felonies (surely a problem of regulations of night sky. statewide concern), then the need for security lighting. preemption is all the greater. Meteor showers are often popular events to bring a community together.29 The astronomy department VIII. Guidelines for Dark Sky laws at the University of Virginia has successfully held meteor shower viewings for residents of • Do not impose requirements retroactively. Charlottesville, Virginia, which were well attended.30 Requirements for particular types of lighting should apply to new construction, or when old Legislation promoting and providing the small construction is renovated. amount of money required to conduct these events would better serve to increase the community spirit • Encourage retrofits of existing property as well as appreciation for the night sky. through tax incentives, or by using public moneys to pay the cost directly. Aspen’s ordinance does evoke one type of small- town atmosphere: the small town depicted in Shirley • Laws should not grant the government a Jackson’s short story “The Lottery.” This time, it is special exemption from the laws applicable to the homeowners and businesses which are selected ordinary homes and businesses. If a particular for the ritual stoning—in order to affirm the city government building has special security needs council’s self-righteousness. which necessitate extra lighting, the law should Page 11  also allow extra lighting for private properties particular circumstances. For example, if the which have special security needs. lighting is covered by a roof or other structure which shields the sky from the light, then the • Light poles should direct most of their light lighting can project upwards. downward, not wasting light into the sky. Some designs point down directly. Other designs • Free-standing lights can be limited to a use a reflective hood (known as a “shoebox”) particular height (such as 25 feet), or the above the bulb, to bounce the light down. height of the building on the Municipalities should use such designs, which property they occupy. So as a general save energy and costs in the long run. policy, lighting • New billboards should have should be direct- Policymakers should, however, recognize that their lights pointing down ed downward, “full cut off” (no light above the horizontal plane from the top, not up from the rather than of the bulb) can make energy use less efficient. bottom. After midnight, if the radiating in all When a light pole uses full cut off (as opposed to billboard is not advertising a directions, but regular “cut off” or “semi-cut off”), then the pole business which is open after there must be radiates very little light laterally (that is, 0 to 10 midnight, billboard owners adaptations for degrees below the horizontal plane). As a result, should voluntarily turn the signs particular cir- the pole illuminates a significantly smaller area of off. cumstances. the ground. Thus, if a parking lot owner wants to cover the entire lot with at least some light, and • Display lighting (as opposed to municipal regulations force the owner to use full security lighting) should be turned off at a set cut off shields on the light poles, then the parking time after the store is closed at night. lot owner will have to use more poles, which will be spaced relatively closer together. As a result, more • Huge light projections—such as from car electricity will be used to illuminate the parking lot. dealerships—that travel far beyond the So the aesthetic environmental gain (no upward commercial property from which they originate light from the parking lot) must be balanced against can be limited to use at particular times, and the environmental loss (more energy in particular directions. There is no problem ...the extra elec- used). And the extra electricity about applying such regulations to existing tricity expense expense imposed on the parking advertising, because the government would not imposed on the lot owner (and, necessarily, on the be requiring the advertiser to spend money to parking lot owner customers of the parking lot) must be change the equipment. Rather, regulation of (and, necessarily, considered. long-distance light is similar to regulation of the customers of sound trucks or bullhorns. Reasonable time, the parking lot) Policy makers should also understand place, and manner regulations protect the must be consid- that even full cut off will not public from annoyance. ered. eliminate all sky glow, because some downward-directed light will • Some security lights, depending on the bounce off the ground, or bounce off particular needs of an area, can be set so that reflective objects (such as the metal and glass on they are only activated by motion detectors, automobiles) and then travel into the sky. and will automatically turn off after a particular period of time. • So as a general policy, lighting should be directed downward, rather than radiating in all • The International Dark Sky Association directions, but there must be adaptations for provides a list of outdoor lighting fixtures Page 12  which minimize upward escape of light. www. darksky.org/fixtures/fixtures.html. The website of the Illuminating Engineering Society of North America, www.iesna.org, also has a great deal of information about lighting issues although, unfortunately, much of the material is available only to members. • Property-owners very near astronomy research facilities should consider the use of low pressure sodium lights (LPS), because LPS light is emitted in a narrow wave spectrum; as a result, telescope filters have an easy time blocking out LPS light. LPS lights should not be encouraged for general use, because their color is sometimes difficult to distinguish from a yellow traffic light. Moreover, LPS lights require a large lamp, and the light distribution is consequently more difficult to control. The above list of ideas is not a full catalogue of reasonable Dark Skies laws. But it is a good starting point, and it shows that there are many ways to protect the important interests of people who love viewing the beautiful night sky, while also protecting the safety, property, and liberty interests of everyone else. Page 13 Copyright © 2006, Independence Institute 7 Center for Astrophysics and Space Astronomy. “The FUSE Mission.” http://casa.colorado.edu/ResearchProjects/arc/. Other participating universities include the University of INDEPENDENCE INSTITUTE is a non-profit, Colorado, the University of Chicago, the Institute for Advanced non-partisan Colorado think tank. It is governed Study (a private organization in Princeton, New Jersey), Johns Hopkins University, New Mexico State University, Princeton by a statewide board of trustees and holds a 501 University, the University of Washington, and Washington State (c)(3) tax exemption from the IRS. Its public policy University. No significant optical telescope research is per- formed in the United States east of the Mississippi River. research focuses on economic growth, education 8 StarDate Online. “How do I find a good site for stargazing?” reform, local government effectiveness, and http://stardate.org/resources/faqs/faq.php?id=62 Constitutional rights. 9 Western Colorado Astronomy Club. “Maps” http://www.colo- radowestastronomy.org/cnmmap.html 10 JON CALDARA is President of the Independence One topic not addressed in this Issue Paper is a property owner casting unwanted light onto someone else’s property. Institute. If you enjoy your dark backyard at night, your enjoyment may be lessened by light from your neighbor’s floodlights which intrudes into your yard. Such an intrusion is a form of trespass, DAVID KOPEL is Research Director of the and a legitimate such for government regulation. But the topic Independence Institute. is beyond the sky-centric focus of this Issue Paper. Another topic not addressed in this Issue Paper is lighting con- ADDITIONAL RESOURCES on this subject can trol to protect wildlife. For example, sea turtles find their way to the ocean by looking for light reflecting off the water. Artificial be found at: http://www.IndependenceInstitute.org lighting on beachfronts can confuse the nesting and movement or by contacting the following organizations: habits of turtles. See http//www.turtles.org/threats.htm. For more, see Catherine Rich & Travis Longcore, eds., Ecological Consequences fo Artificial Night Lighting (Wash.,D.C.: Island NOTHING WRITTEN here is to be construed Pr., 2005). as necessarily representing the views of the 11 To be precise, the Big Dipper is an “asterism” (a sub-unit) of Independence Institute or as an attempt to influence the constellation Ursa Major (the Great Bear) and the Northern Cross is an asterism of Cygnus (the Swan). And to be more any election or legislative action. precise, all the visible stars rotate around the North Star, just as hands rotate around the center of a clock. So when we say that the Big Dipper is, for example, below and to the left of PERMISSION TO REPRINT this paper in whole the North Star, we mean that it is below and to the left of the or in part is hereby granted provided full credit is North Star in the evenings at certain times of the year. At other times of the year, when Big Dipper is below and to the left of given to the Independence Institute. the North Star during its daily rotation, the sun is out, so all the stars are invisible. Endnotes 12 New Orleans Gas-Light Co. v. Louisiana Light & Heat 1 Producing & Manuf’g Co. and others 115 U.S. 650, 658 Michael Loatman is a candidate for a Juris Doctor degree (1885), citing 7 Knight, c. 21. Also citing Thomas Babbington at the University of Virginia School of Law. David B. Kopel is Macaulay, The History of England from the Accession of James Research Director of the Independence Institute. Both Loatman II, volume 1, chapter 3, which states: and Kopel are amateur astronomers. We would like to thank It ought to be noticed that, in the last year of the reign of Brian Barnett, Clayton Cramer, Michael King, Alberto C. Sadun, Charles the Second [1685], began a great change in the and commenters from the Volokh Conspiracy weblog (www. police of London, a change which has perhaps added volokh.com) for helpful suggestions. The opinions in this article as much to the happiness of the body of the people as are those of the authors alone, and any errors are their respon- revolutions of much greater fame. An ingenious projector, sibility. named Edward Heming, obtained letters patent conveying 2 Their website is http://www.darksky.org. to him, for a term of years, the exclusive right of lighting 3 up London. He undertook, for a moderate consideration, Some of the people who hope to use Dark Skies laws to to place a light before every tenth door, on moonless encourage other people to go to bed earlier are rather hypo- nights, from Michaelmas to Lady Day, and from six to critical, since amateur astronomers often stay awake so they twelve of the clock. Those who now see the capital all the can work in the darkest period of the night. year round, from dusk to dawn, blazing with a splendour 4 Comets would be among the exceptions, since some comets beside which the illuminations for La Hogue and Blenheim have not been visible from the earth in the era of powerful would have looked pale, may perhaps smile to think of telescopes. Heming’s lanterns, which glimmered feebly before one 5 Even a still atmosphere will somewhat interfere with the tele- house in ten during a small part of one night in three. But scope’s reception. such was not the feeling of his contemporaries. His scheme was enthusiastically applauded, and furiously attacked. 6 A list of the world’s largest telescopes can be found at http:// The friends of improvement extolled him as the greatest of www.seds.org/billa/bigeyes.html. all the benefactors of his city. What, they asked, were the Page 14  boasted inventions of Archimedes, when compared with ments involved in changing the light sources are almost always the achievement of the man who had turned the nocturnal going to be more costly to businesses (and therefore, ultimately shades into noon-day? In spite of these eloquent eulogies more costly to consumers) than the lower electricity bills the IDA the cause of darkness was not left undefended. There were predicts citizens will receive as a result of new light fixtures. fools in that age who opposed the introduction of what was 28 The City of Aspen lists preserving the small town charac- called the new light as strenuously as fools in our age have ter of Aspen as a main reason for passing its restrictive light opposed the introduction of vaccination and railroads, as ordinance. See City of Aspen Code, “Outdoor Lighting,” § strenuously as the fools of an age anterior to the dawn of 26.575.150 http://www.ordlink.com/codes/aspen history doubtless opposed the introduction of the plough 29 and of alphabetical writing. Many years after the date of See Sky and Telescope Magazine’s website for the dates Heming’s patent there were extensive districts in which no of upcoming meteor showers. http://skyandtelescope.com/ lamp was seen. observing/objects/meteors/article_588_1.asp 30 University of Virginia Department of Astronomy. “Leonids For more on the expanding mandate for street lighting in 2002”. http://www.astro.virginia.edu/Leonids2002/ London as a result of crime control concerns, see J.M. Beattie, Policing and Punishment in London: 1660-1750 (N.Y.: Oxford Univ. Pr., 2001), pp. 207-25. 13 International Dark Sky Association. “An Introduction to the Issues of Light Pollution.” http://www.darksky.org/handouts/ bc_intro_lp.pdf 14 Lawrence W. Sherman, et al. Preventing Crime: What Works, What Doesn’t, What’s Promising, National Institute of Justice, http://www.ncjrs.org/works/wholedoc.htm 15 Id. 16 Id. 17 Brandon C. Welsh, & David P. Farrington, Effects of Improved Street Lighting on Crime: Protocol for a Systemic Review. http:// www.aic.gov.au/campbellcj/reviews/2003-11-StreetLighting. pdf 18 David P Farrington & Brandon C. Welsh, “Improved Street Lighting and Crime Prevention,” 19 Justice Quarterly 313 (no. 2, June 2002). 19 David P. Farrington & Brandon C. Welsh, Effects of improved street lighting on crime: a systematic review. http://www. homeoffice.gov.uk/rds/pdfs2/hors251.pdf 20 National Crime Prevention Council, Lighting Up for Crime Prevention http://www.ncpc.org/ncpc/ncpc/?pg=2088-8888 21 Terance D. Miethe, “Citizen-Based Crime Control Activity and Victimization Risks: An Examination of Displacement and Free- Rider Effects,” 29 Criminology 419 (1991). 22 Simon Hakim et al., “Estimation of Net Benefits of Residential Electronic Security,” 13 Justice Quarterly 153, 161 (1996). 23 Patricia Miller, “City officials hear comments on dark skies”, Durango Herald http://durangoherald.com/asp-bin/article_ generation.asp?article_type=news&article_path=/news/04/ news040212_2.htm 24 Id. 25 See Colo. Rev. Stats. §§ 24-82-901 & 902. 26 City of Boulder. “Boulder Planning & Development Services Energy Code and Green Points Program Changes” http://www. ci.boulder.co.us/buildingservices/codes/lightingord.htm 27 The IDA estimates that Americans are wasting approximately $1.5 billion dollars in electricity costs per year, through unnec- essary upward-focused public lighting. International Dark Sky Association, “An Introduction to the Issues of Light Pollution,” http://www.darksky.org/handouts/bc_intro_lp.pdf. If the esti- mate is accurate, then the cost of the extra electricity works out to about five dollars per resident of the United States and about seven dollars per adult. (Based on the Census Bureau estimate of a U.S. population of 291 million.) The large capital invest- Page 15 13952 Denver West Parkway • Suite 400 • Golden, Colorado 80401-3141 www.IndependenceInstitute.org • 303-279-6536 • 303-279-4176 fax