Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.astronomy.com/~/media/import/files/pdf/c/c/f/alp0604.pdf Дата изменения: Tue Oct 12 03:29:53 2010 Дата индексирования: Tue Oct 2 14:03:27 2012 Кодировка:

{ AMATEUR ASTRONOMY }

Fighting light pollution is not a hopeless task, but it requires backyard astronomers to get active politically /// BY MICHAEL E

. BAKICH

night sky
the

Reclaim


EVERYONE WHO LOVES OBSERVING THE NIGHT SKY, OR TAKES PHOTOS OF IT, soon becomes aware of a Big Problem. Excess nighttime lighting, generally called light pollution, has increased much during the last several decades and continues to grow at a high rate. In today's world, the most immediately endangered natural resource is the dark night sky. For much of the population of North America and Europe, the night sky is no longer black, or even dark. Instead, almost bereft of stars, it glows yellow-orange, lit by poorly designed fixtures and spillover light from human activities. Satellite images of Earth no longer show the night side of our planet as dark. For some people born in the 1980s or later, it's possible the only celestial object they've ever seen in the night sky is the Moon.

Few, if any of us, favor the utter abolition of outdoor lighting. It is necessary for safety and security during work or recreational activities. Other lighting, such as that which spotlights historical buildings, parks, shopping areas, or advertising, may not be entirely necessary, but it is desirable to many. These lighting situations would be tractable if they didn't come embedded in more problematic ones.

For example, everyone has encountered lighting that seems to serve no purpose, is poorly designed, or is in need of repair. Worse, some lighting fails to achieve its aim -- as, for instance, much security lighting. A 1998 study commissioned by the United States Department of Justice concluded there is no statistically significant (continued on page 42)

BAD URBAN LIGHTING robs most city dwellers of a dark night sky, not to mention they're paying extra in taxes because poorly designed lights waste electricity. Read on for some ideas on how to fight the growing problem of light pollution where you live. MICHAEL E. BAKICH


The bright

night sky

Satellite imagery of the nighttime Earth lets scientists construct a global light pollution map. Most Astronomy readers, and others in the developed world, live within one of the bright spots, while the dark land-areas are usually rural, thinly populated, or poor. Backyard astronomers gravitate toward the dark regions, even as some cities take steps to help slow the spread of light pollution.

CANADA has a number of "Dark Sky Preserves," where lighting ordinances are enforced aggressively. Other locations are beginning to follow suit. Even cities are taking notice, urged on by Canadian amateur astronomers.

BELGIUM has an annual National Light Pollution Awareness Day to promote a better nighttime environment.

IRELAND and ARGENTINA are the latest countries to have affiliate organizations join IDA. IDA sections -- for the distribution of educational information -- are being set up within both countries.

TUCSON, ARIZONA, has had outdoor lighting ordinances since 1970. The ordinances save money, enhance businesses, and help preser ve the beauty of the night sky. Tucson has grown since 1970 to more than 800,000 people, yet the sky glow at the major obser vatories near Tucson has increased very little over that period. FLAGSTAFF, ARIZONA, was recently proclaimed by IDA to be the first ever DarkSky City, having taken many steps to reduce light pollution.

THE UNITED STATES now has a number of state ordinances dealing with nighttime lighting, with more coming. Many communities are enacting such ordinances to help control the adverse impact on their nighttime environment. IDA is producing a "model lighting ordinance" to help these communities in their efforts. What is your community doing?

CHILE has national legislation for a number of its regions to promote quality lighting and to preser ve the night environment. The government recognizes the economic value of such activities.

ENGLAND has many organizations involved in educational efforts geared toward better nighttime lighting. The Campaign for Dark Skies is an organization allied with IDA that works with the Institute of Lighting Engineers, the Council for the Protection of the Rural Environment, and various governmental bodies in these efforts.

ALL LIGHT POLLUTION MAPS: P. CINZANO, F. FALCHI (UNIVERSITY OF PADOVA), C. D. ELVIDGE (NOAA NATIONAL GEOPHYSICAL DATA CENTER, BOULDER); COPYRIGHT ROYAL ASTRONOMICAL SOCIETY; REPRODUCED FROM THE MONTHLY NOTICES OF THE RAS BY PERMISSION OF BLACKWELL SCIENCE.

40 a s tronomy

///

june 04


THE CZECH REPUBLIC enacted a national law in 2002 to eliminate light pollution. JAPAN'S amateur astronomy community is active in distributing IDA educational material related to light pollution. Top on the agenda is line-of-sight glare, a major problem in Japan.

AUSTRIA has raised awareness of light pollution by having a nationwide star counting activity. A large number of citizens participate. This program gets people outside, looking up, and becoming aware of their environment.

AUSTRALIA has national standards for lighting, including the control of obtrusive lighting. The city of Sydney, New South Wales, also has an aggressive outdoor lighting policy, and the results from this policy are benefiting its citizens. Sydney is renowned as a tourist destination, and good lighting helps enhance that reputation. GREECE has an extensive educational effort within its schools regarding light pollution. The school system has found light pollution to be one of the best inter-disciplinary topics, as it involves science (astronomy, physics, biology, etc.), the environment, politics, and engineering.

ITALY has enacted legislation controlling nighttime lighting in nine of its twenty regions. Rome is committed to relamping 100,000 lights by 2010 in order to reduce light pollution and save energy.

/// THE INTERNATIONAL DARK-SKY ASSOCIATION
The International Dark-Sky Association (IDA) was incorporated in 1988 with the goal of preser ving dark skies and improving the nighttime environment for everyone. It has about 11,000 members from each of the fifty states and from more than seventy other countries. IDA has contacts with national and international organizations that deal with outdoor lighting or that have an interest in the issue. IDA staff and members are actively involved with these organizations. Lighting standards are changing as a result of their efforts, which bodes well for the future. IDA's web site (www.darksky.org) contains lots of material: information sheets, slides, images, PowerPoint presentations, and links to important sites. "Many members contact IDA for advice on promoting good lighting and for resources," says Dave Crawford, IDA president. "We need to attract more members if we are to make a continued positive impact on the problem. As the saying goes, think globally, act locally."

w w w.a stronomy.com

41


(continued from page 39)

evidence that street lighting affects the level of crime. The study found, however, that increased lighting decreases the fear of crime. In essence, poor lighting doesn't aid security; it simply makes you feel safer. In 2002, CNN reported on a study conducted by scientists at the University of Padua, Italy, and the United States National Oceanic and Atmospheric Administration. The researchers found that a truly dark, starry sky is unavailable to two-thirds of the world's population. This includes 99 percent of people in the continental United States and Western Europe. The study also measured for the first time how light degrades the view of the stars in specific places around the globe. The researchers discovered that in some regions, true night never occurs because of illumination from lights located in nearby cities and towns. The study also concluded 40 percent of the population of the United States and 10 percent of the world's people live where it never gets dark enough for eyes to become dark-adapted.

What your eyes need
Dark adaptation -- your eyes becoming fully adjusted to low light levels -- is the key to the night-sky experience. It's what makes the starlit heavens take your breath away. Once a person's eyes become dark-adapted, lower levels of illumination than those currently being used outdoors at night become acceptable. The greatest human-related problems arise when eyes must move from dark to light and back again rapidly. Under these conditions, eyes really don't function well in either situation. The problem worsens with age, too. Older people encounter difficulties with overly bright nighttime lighting. Changes within the eye due to age, such as diminished dark-adaptation
Michael E. Bakich is an associate editor of Astronomy.

NO DARK SKIES EXIST IN CENTRAL EUROPE, where one city's sky glow merges with its neighbor 's. Only sparsely populated regions, and relatively poor rural ones, have dark skies. (The bright lights in the middle of the North Sea come from oil-well drilling platforms.)

speed, can prove dangerous. Entering a car under a brilliantly lit service-station canopy and then driving out onto a highway with much dimmer lights (or none) places an elderly driver -- not to mention anyone or anything in the way -- at a terrible disadvantage. Older eyes are also more sensitive to glare, particularly from bluer-colored light sources. The eye, especially at night, does not see blue light well. Thus, bluish light sources like mercury-vapor lamps must consume many more watts to look as bright as yellowish sources such as sodium-vapor lamps. The International Dark-Sky Association (IDA) estimates that the United States alone wastes

more than one billion dollars each year in energy costs for unnecessary lighting.

Steps you can take
I have a bit of personal experience in helping to enact a lighting ordinance in El Paso, Texas, where I lived for several years before joining Astronomy. (At press time, the City Council had yet to vote on the ordinance -- but it's been in their hands for only 21/2 years!) The people most responsible for El Paso's movement toward an effective lighting ordinance are John Peterson and Cory Stone, director and assistant director of the Gene Roddenberry Planetarium. They have a four-part strategy

/// SUCCESS STORY
In June 2003, the United States Border Patrol activated twenty light towers along the Arizona border with Mexico. Each tower had three, extremely bright metal-halide lights, which caused considerable sky glow and light trespass. At the request of nearby residents, the Border Patrol has shielded and redirected the lights. They are no longer distinguishable from the existing border lights. IMAGES: DOUG SNYDER

BEFORE

AFTER

42 a s tronomy

///

june 04


NORTH AMERICA BLAZES with light, especially in the eastern states, where dark skies hardly exist at all. Pockets of darkness grow, however, as one travels west. In particular, notice how city lights decrease west of about the 95th meridian. That longitude, roughly where annual rainfall drops below 20 inches, is often considered the beginning of the West.

they recommend for any astronomy club or individuals wishing to work within the political system to reduce light pollution. First, focus on economics. The best advice is to leave the astronomy-related arguments at home. Emphasize what everyone understands: money. You can mention other benefits such as security and night-sky issues, but dollars (or euros) get the most attention. Second, make it easy for the politicians. Provide copies of lighting ordinances from other cities, statistics and economic benefit reports, engineering and safety reports, etc. Then go the extra mile by composing a first draft of the ordinance your group is proposing.

Third, get many people involved and keep them interested. Draft letters that can be mailed or e-mailed to all members of the governing body. Make the messages short and non-confrontational, and be sure each writer identifies herself or himself as a voter. Write letters to your local newspaper and to TV and radio stations. Get schools involved. Host astronomy events in town and pass out lightpollution information to everyone who attends. Finally, choose a "point person" who has a pleasant manner, is patient and not easily irritated, and who will be able to attend the meetings of the governing authority. The key lies in being low-key: Avoid a vocal activist, however

helpful she or he has been in your club. Such people often come across as confrontational.

It's good for everyone
As fervent as we are in attempting to preserve (or return to) a dark night sky, it's important to remind people that light pollution is bad for more than just the astronomical community. As IDA's Lighting Code Handbook says, "Bad lighting hurts everyone. It starts a cascade of negative consequences -- beginning with the loss of our views of the heavens, continuing through falling levels of safety and utility, irritation of neighbors and wildlife, disturbance of the rhythms of day and night that are vital to many natural systems, damage to the aesthetic appearance of our communities, wasted monetary and natural resources used to produce wasted light, and increased air pollution and carbon dioxide levels from wasted fossil fuels. There is nothing good that comes from bad lighting." Dave Crawford, president of IDA, says, "Light pollution is not the inevitable price of progress. In fact it's the reverse -- a sign of inefficiency and harm to the environment." X
To learn more about combating light pollution, visit www.astronomy.com/toc w w w.a stronomy.com 43

/// THREE WAYS TO SAVE ENERGY (AND MONEY)
1) Turn down the lights. When we use lights brighter than those recommended by engineers, we waste money because human eyes quickly adapt to the higher levels of illumination. For additional energy savings, install lower wattage bulbs in areas inside and outside your home or business (such as hallways and yards) where bright lights are not needed for specific activities. 2) Pick the right lamp for the job. Selecting high-pressure sodium lights saves 40 percent in operating costs over metal-halide lamps and 150 percent over mercury-vapor lights. 3) Shield all lights. Installing full cutoff shields will direct the light to where it's needed, reducing dangerous glare -- with the side benefit of preser ving the sky and allowing lower wattage lamps to be used.