​Dark Sky Friendly Lighting Takes Into Consideration Five Essential Design Principles:
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• Useful - Start with natural darkness - Before installing or replacing a light, determine if it is needed, and use light only when and where it is needed. Consider its impact on wildlife and the environment, and use of alternative non-toxic reflective or fluorescent materials.

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• Targeted - Use “full cutoff” - sometimes called fully shielded -- light fixtures where no part of the light source or its reflective and refractive elements are visible above the horizontal. With these fixtures light is aimed only downward where it is needed, not outward and upward where it is wasted.​

 

• Intensity - Do not over-light an area with excess "lumens." This saves money and energy. Reflected light off the ground and other surfaces can also contribute to light pollution, so it is important to use only enough light to do what is actually needed.

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• Color - Use lighting which is "warm-white." This light is not as harsh and is scattered by the atmosphere less than “cool” blue-white light, and protects our health - and the night sky - much better. A "color temperature" of 2200 K or less is ideal.

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• Controlled Period of Illumination - Shut off lights when not needed. Turn off lights when not in use, and incorporate automatic timers or motion sensors which improve security and also save money and energy.

Necessary? Alternatives?

Shielding

Color Temperature

Intensity

Controlled Period

Adapted from Mont-Megantic Dark Sky Reserve

Light pollution is one of the easiest environmental problems to fix - in many instances it only takes the flip of a switch.

To successfully manage light pollution and its effects on wildlife and the environment, it must be recognized and treated as any other form of environmental pollution. Incorporating the five principles above into outdoor lighting codes, combined with public education awareness and regulatory compliance is the best - and perhaps only - way to conserve the rapidly disappearing night sky and protect the health of ecosystems affected by excessive light at night.

The IDA has adopted a policy implementing the five essential lighting design principles detailed above for responsible outdoor lighting. The policy, known as Values-Centered Outdoor Lighting, is intended to build upon these principles and recognize that addressing them in isolation from one another is inadequate towards solving the rapidly increasing global problem of light pollution.

​Examples of poor versus excellent lighting fixtures for higher efficiency and protecting the night sky, eliminating glare, and helping to prevent light from trespassing onto your neighbor's property.  Many ​dark sky friendly fixtures will have an​ DarkSky Seal of Approval.

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​Click the pictures below for each organization for more detailed information on dark skies & light pollution.

​Have a light fixture that has too high of a color temperature - too much blue - and the light source can't be easily replaced? An inexpensive movie and stage light filter can correct this lighting to be ​warm versus cool white: ​

www.darkskylighting.co.uk/products/uv-blue-blocker-led-lighting-correction-film

The City of Invins, Utah (pop. 9000), retrofitted unshielded and high color temperature parking lot fixtures at the Rocky Vista University College of Osteopathic Medicine’s campus. The picture on the right shows the reduction in glare and blue light from the conversion (left pole) compared to the unconverted parking lights.

The BEST Available Street Lighting

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When first introduced over 10 years ago there was a lack of suitable night sky friendly LED street lighting. This in no longer the case. Research by the Flagstaff Dark Skies Coalition shows that the very best night sky friendly LED street lighting currently available is Narrow Band Amber LED fixtures. There is no reason not to provide this superior LED street lighting.

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​Education is Essential to  Success

Education about light pollution and the importance of a dark nighttime environment is an essential key to raise public awareness, which can lead to changes in policy and behavior. 

Dark Sky Defenders has done dozens of in-depth professional presentations on light pollution throughout the Pacific Northwest and beyond. If your group or organization would like a presentation given to your members, local community, or governmental representatives, please Contact Us for details.

​This educational brochure is available to groups and organizations promoting dark skies, for a minimal cost to cover postage and handling directly from Dark Sky Defenders - contact us for details, a sample, or to schedule a presentation on dark skies and light pollution.