Protecting Dark Skies for Astronomy and Life Lori Allen Director, Kitt Peak National Observatory + AAS Committee on Light Pollution, Radio Interference and Space Debris Need a good image of the night sky as background for this slide Credit: National Park Service

Artificial sky brightness over the U.S. Falchi et al. 2016 Ratio of artificial to natural brightness is 0.01 (black) to 41 (white) This is a recent map of the artificial night sky brightness over the United States. Over much of the US, the artificial sky brightness far exceeds the natural sky brightness.

Artificial sky brightness over the U.S. 99% of the U.S. population lives under light-polluted skies 80% of Americans cannot see the Milky Way Falchi et al. 2016 Ratio of artificial to natural brightness is 0.01 (black) to 41 (white) The result is that most Americans never experience a starry night sky.

And it is getting worse Quality light for a quality life Blue light LEDs are bad for Safety (glare) Health of wildlife Health of humans [AMA 2016] Astronomy TUS PHX Quality light for a quality life Falchi et al. 2016 Even in telescope-rich AZ, light domes are growing And there is even worse news: as broad spectrum LEDs are installed in streetlights and other outdoor lighting fixtures, the sky will grow brighter faster. The threat from broad spectrum LEDs is so serious that even historically dark – protected regions, like near the many research observatories in Arizona, are threatened. The blue light in the broad spectrum or “white light” LEDs (ie, LEDs w/ CCT above 3000K) were the first LEDs to flood the market. These are bad….

Solutions that work Eye-friendly is sky-friendly Shield the light Dim the light Use the right color of light Eye-friendly is sky-friendly 6500K 6000K 3000K The good news is that this is a completely manageable problem. Here are three simple solutions that really work: Shield…. The additional good news is that these solutions work immediately – we can solve this problem at the speed of light!

Holding the brightness at bay Flagstaff / Tucson: 1st dark sky city / 1st OLC Part of the Flagstaff persona since 1958 (Jeff Hall, Director, Lowell Observatory) Phoenix: Selected 2700K LEDs for streetlights Citizen effort led by PHX chapter of IDA Southern California: Palomar Observatory & WRCOG Communities become part of process and share successes (Dan McKenna, Palomar Observatory) I want to share with you a few success stories, to illustrate ways in which solutions can be implemented.

American Astronomical Society Resolution on Light Pollution The AAS endorses IAU 2009 Resolution B5 "In Defence of the Night Sky and the Right to Starlight," affirming that access to a dark night sky is a universal human right, making quality outdoor lighting a worldwide imperative. The AAS endorses the American Medical Association's CSAPH Report 2-A-16 (May 2016) on "Human and Environmental Effects of Light Emitting Diode (LED) Community Lighting”. The AAS calls on all US communities to adopt the following principles for outdoor lighting: 1. Full cutoff shielding: No light should escape above the horizontal from all outdoor light fixtures. 2. Spectral management: Blue light should be minimized everywhere and light sources should be as monochromatic as possible near critical observatory and natural sites. 3. Control of light level: Light levels should be properly matched to location, time, and vehicle and pedestrian traffic, with the added goal of energy efficiency and long-term sustainability. To realize its mission to enhance and share humanity's scientific understanding of the Universe, the AAS calls on all its members to take local action in support of dark skies.

What can you do? Now is the time! Shield, dim, select warm color Give your input to planners, developers, officials Contact the International Dark Sky Association (IDA) Now is the time! Streetlights will all be replaced in next ~5 years LED billboards are proliferating My inheritance was a handful of earth But of sky All the universe -Rafael Arozarena You don’t have to be an astronomer to have an impact on the future of the night sky. shield, dim, select Citizen input is very important – what kind of lighting do you want for your community? A good starting point is to contact the IDA And: It’s in our hands, what kind of sky we will leave for our children