Less than 100 years ago, everyone could look up and see a spectacular starry night sky. Now, millions of children across the globe will never experience the Milky Way where they live. The increased and widespread use of artificial light at night is not only impairing our view of the universe, but it is also adversely affecting our environment, our safety, our energy consumption, and our health.
The Five Principles for Responsible Outdoor Lighting that unite our organizations are based on simple ideas; limit light at night to where and when it is needed, don’t overlight, and be sensitive to environmental concerns.
1. USEFUL – ALL LIGHT SHOULD HAVE A CLEAR PURPOSE
Before installing or replacing a light, determine if light is needed. Consider how the use of light will impact the area, include wildlife and the environment. Consider using reflective paints or self-luminous markers for signs, curb, and steps to reduce the need for permanently installed outdoor lighting.
2. TARGETED – LIGHT SHOULD BE DIRECTED ONLY TO WHERE NEEDED
Use shielding and careful aiming to target the direction of the light beam so that it points downward and does not spill beyond where it is needed.
3. LOW LIGHT LEVELS – LIGHTS SHOULD BE NO BRIGHTER THAN NECESSARY
Use the lowest light level required. Be mindful of surface conditions as some surface may reflect more light into the night sky than others.
4. CONTROLLED – LIGHT SHOULD BE USED ONLY WHEN IT’S USEFUL
Use controls such as times or motion sensors to ensure that light is available when it is needed, dimmed when possible, and turned off when not needed.
5. COLOR – USE WARMER COLOR LIGHT WHERE POSSIBLE
Limit the amount of shorter wavelength (Blue-Violet) light to the least amount needed. 3K or warmer color temperature and fixed mountings must be selected for International Dark Sky Certification.