When the great earth, abandoning day, rolls up the deeps of the heavens and the universe, a new door opens for the human spirit, and there are few so clownish that some awareness of the mystery of being does not touch them as they gaze.
— Henry Beston, The Outermost House (1928)
ALERT: What dark skies protection is missing by focusing on LED CCT... to read more click '+' →
Most discussions about limiting the light pollution impacts of the new white LED lighting revolve around the “correlated color temperature” – or “CCT” of the lights. CCT is a number that describes the “hue” of a white light – is it “warm” white (~2700 K CCT), “neutral” white (~4000 K CCT), or “cool” white (~5000 K CCT)? But CCT limits are the wrong approach to protecting dark skies, because CCT does not accurately indicate how much light pollution a light will cause. Even low-CCT white LEDs (e.g. the IDA-recommended 3000K CCT) have lumen-for-lumen sky glow impacts twice that of HPS, 3X greater than good PC amber LED, and over 5X worse than the dark sky gold-standard LPS or NBA LED! (See our page here for documentation of these ratios.) Do not accept the argument that says “low CCT white LEDs protect dark skies because light pollution will only get 2X worse than it is now, and this is an improvement because it might have gotten 5X worse!” To prevent continued degradation to our starry skies we must set our standards higher. There are practical solutions that will achieve true protection – see our pages on LED Lighting and Dark Skies, and FDSC “First Dark-Sky City” lighting recommendations – Commercial and Roadway Lighting Tips.
Flagstaff Dark Skies Coalition
Our Mission: To celebrate, promote, and protect the glorious dark skies
of Flagstaff and Northern Arizona
To demonstrate by example strategies that are proven to protect and improve dark skies
Setting the Gold Standard for night sky protection
A dark, star-filled night sky is often thought of as important for astronomy or research. Though this is true, the grandeur of the night sky is much deeper and broader, and accessible to anyone. We find the beauty and meaning of natural night is best expressed by poets and writers, such as Henry Beston.
Although astronomers and astronomy are important (some of our best friends are astronomers), protecting the night sky just for astronomers would be like protecting Grand Canyon just for geologists. Yet no one ever seems to think so narrowly about the Canyon; it is our hope that after looking through our website you may think more broadly about the night sky.
As the international dark sky movement began in Flagstaff in 1958, our community has always been keenly aware of the special value of the night sky. The Flagstaff Dark Skies Coalition and the greater community of Flagstaff are proud to remain world leaders in practical and successful dark sky protection.
This page was last updated 28th September, 2023
To celebrate, promote, and protect the glorious dark skies of Flagstaff and northern Arizona.