Light pollution A problem for humanity Donald

Light pollution : A problem for humanity Donald R. Davis International Dark-sky Association 8 June, 2004 International Dark-Sky Assocation

The Inspirational “Mortal as I am, I know that I am born for a day. But when I follow at my pleasure the serried multitude of the stars in their circular course, my feet no longer touch the earth. ” -- Ptolemy, c. 150 AD "Can we see the whole of life or only know a hemisphere of it before death? I've no idea of the answer myself. But the sight of stars always sets me dreaming…" -- Vincent Van Gogh "At night make me one with the darkness; in the morning make me one with the light. " -- Wendell Berry Startling fact: For 80% of the US population, two-thirds of the EU population and one-fourth for the world population, night never comes. International Dark-Sky Assocation

Startling fact: Two thirds of the US population cannot see the Milky Way with the unaided eye from their back yards. Why not? International Dark-Sky Assocation

International Dark-Sky Assocation

Light pollution has negative effects on: • • Wildlife. Environment. Landscape. Human Activities. International Dark-Sky Assocation

The Earth is really bright! International Dark-Sky Assocation

International Dark-Sky Assocation

IDA’s Goals • To preserve and protect the nighttime environment and our heritage of darkskies through quality outdoor lighting. • Membership based. Members, from all 50 states and 70 other countries. 414 organizations. International Dark-Sky Assocation

IDA Statistics • • • Total Members — nearly 11, 000 Organizational Members — 569 Lifetime Members — 203 Newsletters Issued — 57 Information Sheets Published — 193 International Dark-Sky Assocation

International Dark-Sky Assocation

Bottom Line: • • Environmentally responsible, Economically sensible. Good lighting has great value! We all win! International Dark-Sky Assocation

"Now I think we are small enough. Let's call it a night. “ -- Theodore Roosevelt, a comment after marveling at the enormity of the number of visible stars International Dark-Sky Assocation

Sky Brightness Measurement Examples of Existing Programs 1) The National Park Service Night Sky Project. 2) Sky Brightness mined from an automated search program. International Dark-Sky Assocation

Dark Skies in National Parks: Measuring Night Sky Quality with a Wide Angle CCD Camera Dan Duriscoe Death Valley National Park Chad Moore Bryce Canyon National Park Christian Luginbuhl U. S. Naval Observatory, Flagstaff, Arizona International Dark-Sky Assocation

International Dark-Sky Assocation

DATA MINING OF AUTOMATIC TELESCOPE ARCHIVES FOR NIGHT SKY BRIGHTNESS MONITORING Erin M. Craine University of Arizona and Global Network of Astronomical Telescopes Presented at the Meeting of the International Dark Sky Association Tucson, AZ March 2004 International Dark-Sky Assocation

GN AT MOTESS “ 3 -Shooter” Prototype • 36 -cm Newtonian reflector • f/5 focal ratio • 50 arcmin FOV • scan mode • 12 sq deg of sky/hr under construction ^ < operational International Dark-Sky Assocation

GN AT System Images • 1024^2 px • 16 bit • 50 arcmin • 191 sec int • FITS format • clear channel • standard 2 x 2 -in filters International Dark-Sky Assocation

Examples of night sky brightness measures Graphs B and D represent dark nights just over a year apart. The later image is about 10% brighter than the earlier image, which is consistent with normal night to night variations, suggesting that the observatory site brightness has not increased significantly during the intervening year. International Dark-Sky Assocation

Sky Brightness Modeling • Significant economic benefits from the astronomy, optics, and tourism industries. • A tool is needed to predict the impact of growth on dark skies. • Environmental preservation is of increasing importance in many places. • Quality data is key to designing good policies.

IDA Sky Brightness Modeling Project • Modify the Garstang code to add detailed models of cities and visualization capability. • Validate the model: Compare predictions to actual sky brightness measurements • In association with local jurisdictions, model the impact of future growth on sky brightness under a variety of scenarios.

Code Improvements and Future Work • Update the integration algorithms. • Allow each segment of a city to have its own light intensity and distribution. Use as many segments as needed to represent the city. • Validate the angular distribution assumptions. • Visualize the output of the model. International Dark-Sky Assocation

IDA Sky Brightness Modeling Project • Funding secured from two counties in Arizona. • Code modifications to be completed by July, 2004. • Validation phase completed by September, 2004. • Modeling and final report by Jan. 2005.

Summary • Several projects underway to measure sky brightness for specific objectives. • Ongoing sky brightness monitoring at major observatories still needs to be implemented. • Inexpensive sky brightness measurement instrument still needs to be developed. • Modeling project underway to generate a general tool for sky brightness prediction.

Conclusions • • There is a problem. It is still getting worse most places. Why do we tolerate it? Solutions exist. Good lighting is the key. It has value! Help build awareness. Get involved! With good lighting, we all win. International Dark-Sky Assocation

Flagstaff Lighting and Land Use Project Kevin Pick, Don Davis, Wes Lockwood, Chris Luginbuhl Funded by Coconino County and IDA

IDA award: International Dark Sky City International Dark-Sky Assocation

Project Goals Ø How much outdoor light is produced by different types of users? Ø What fraction of outdoor lighting goes up? ØHow effective has the Outdoor Lighting Code been? Ø How do our results compare with standard numbers used in computer models, e. g. the Garstang code? International Dark-Sky Assocation

Data Collection: How? 1. Roadway and sports lighting information from the City of Flagstaff and Arizona Dept of Transportation. 2. Inventory of large shopping centers 3. On-site surveys of a sample of commercial sites 4. Lighting inventory flyers distributed to single family homes International Dark-Sky Assocation

Data Collection: On-the-ground survey Ø 45 sites targeted, including most shopping centers, and smaller samples of other uses Ø On site, fixtures counted, photographed, and marked on maps Ø Wattage and bulb type obtained for each fixture Ø Total mean lamp lumens calculated for each site surveyed Ø An average CU and “dirt depreciation” for each fixture type applied to the lumen count International Dark-Sky Assocation

Data Collection: Residential Ø 500 survey forms distributed to five residential neighborhoods – 115 were returned Ø Total mean lamp lumens calculated for each home Ø An average CU and “dirt depreciation” applied to the lumen count International Dark-Sky Assocation

Data Collection: Residential survey form International Dark-Sky Assocation

Results: How is lighting used? 117 million lumens Other white light 8 million lumens 1. 4 megawatts Other white light 200 k. W International Dark-Sky Assocation

Results: Where is Lighting Used? Lighting and sky glow proportions International Dark-Sky Assocation

Results: Where does uplight come from? Sports lighting off Sports lighting on 1/3 of Flagstaff’s sky glow comes from unshielded sources International Dark-Sky Assocation

THE CODE AND DARK-SKY AWARENESS IS WORKING! Measurements by Lockwood show no increase in sky brightness in Flagstaff in the past 25 years despite a doubling of the population. International Dark-Sky Assocation

Sky brightness changes since 1975 International Dark-Sky Assocation

International Dark-Sky Assocation