International Dark-Sky Assocation
Light pollution : A problem for humanity
Donald R. DavisInternational Dark-
sky Association8 June, 2004
International Dark-Sky Assocation
The Inspirational
Startling fact: For 80% of the US population, two-thirds of the EU population and one-fourth for the world population, night never comes.
“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
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
International Dark-Sky Assocation
IDA’s Goals
• To preserve and protect the nighttime environment and our heritage of dark-skies 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
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 MooreBryce Canyon National Park
Christian LuginbuhlU.S. Naval Observatory, Flagstaff, Arizona
International Dark-Sky Assocation
International Dark-Sky Assocation
International Dark-Sky Assocation
DATA MINING OF AUTOMATIC TELESCOPE ARCHIVES FOR
NIGHT SKY BRIGHTNESS MONITORING
Erin M. Craine
University of Arizonaand
Global Network of Astronomical Telescopes
Presented at the Meeting of the International Dark Sky Association Tucson, AZ March 2004
International Dark-Sky Assocation
MOTESS “3-Shooter” Prototype• 36-cm Newtonian reflector• f/5 focal ratio• 50 arcmin FOV• scan mode• 12 sq deg of sky/hr
G NA T
under construction ^
< operational
International Dark-Sky Assocation
System Images
• 1024^2 px• 16 bit• 50 arcmin• 191 sec int• FITS format• clear channel• standard 2x2-in filters
G NA T
International Dark-Sky Assocation
Examples of night sky brightness measures
Sky Brightness 11/14/2001
0
10000
20000
30000
40000
50000
60000
70000
0:00:00 2:24:00 4:48:00 7:12:00 9:36:00 12:00:00 14:24:00 16:48:00
U.T.
Bri
gh
tne
ss
Sunset
Moonrise
Sunrise
B Sky Brightness 12/4/2002
0
10000
20000
30000
40000
50000
60000
70000
0:00:00 2:24:00 4:48:00 7:12:00 9:36:00 12:00:00 14:24:00 16:48:00
U.T.
Bri
gh
tnes
s
Sunset Sunrise
D
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 ModelingSky 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.
International Dark-Sky Assocation
IDA Sky Brightness Modeling Project
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.
International Dark-Sky Assocation
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
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.
International Dark-Sky Assocation
Summary 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.
International Dark-Sky Assocation
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 Flagstaff Lighting and Land Use ProjectUse Project
Flagstaff Lighting and Land Flagstaff Lighting and Land Use ProjectUse Project
Kevin Pick, Don Davis, Wes Lockwood, Chris Luginbuhl
Funded by Coconino County and IDA
International Dark-Sky Assocation
IDA award: International Dark Sky City
International Dark-Sky Assocation
Project GoalsProject Goals
How much outdoor light is produced by different types How much outdoor light is produced by different types of users?of users?
What fraction of outdoor lighting goes up?What fraction of outdoor lighting goes up?
How effective has the Outdoor Lighting Code been?How effective has the Outdoor Lighting Code been?
How do our results compare with standard numbers used How do our results compare with standard numbers used in computer models, e.g. the Garstang code?in computer models, e.g. the Garstang code?
International Dark-Sky Assocation
Data Collection: How?Data Collection: How?
1.1. Roadway and sports lighting information from the Roadway and sports lighting information from the City of Flagstaff and Arizona Dept of Transportation.City of Flagstaff and Arizona Dept of Transportation.
2.2. Inventory of large shopping centersInventory of large shopping centers
3.3. On-site surveys of a sample of commercial sites On-site surveys of a sample of commercial sites
4.4. Lighting inventory flyers distributed to single family Lighting inventory flyers distributed to single family homeshomes
International Dark-Sky Assocation
Data Collection: On-the-ground Data Collection: On-the-ground surveysurvey
45 sites targeted, including most shopping centers, 45 sites targeted, including most shopping centers, and smaller samples of other usesand smaller samples of other uses
On site, fixtures counted, photographed, and marked On site, fixtures counted, photographed, and marked on mapson maps
Wattage and bulb type obtained for each fixtureWattage and bulb type obtained for each fixture
Total mean lamp lumens calculated for each site Total mean lamp lumens calculated for each site surveyedsurveyed
An average CU and “dirt depreciation” for each An average CU and “dirt depreciation” for each fixture type applied to the lumen countfixture type applied to the lumen count
International Dark-Sky Assocation
Data Collection: ResidentialData Collection: Residential
500 survey forms distributed to five residential 500 survey forms distributed to five residential neighborhoods – 115 were returnedneighborhoods – 115 were returned
Total mean lamp lumens calculated for each homeTotal mean lamp lumens calculated for each home
An average CU and “dirt depreciation” applied to An average CU and “dirt depreciation” applied to the lumen countthe lumen count
International Dark-Sky Assocation
Data Collection: Residential survey form
International Dark-Sky Assocation
Results: How is lighting used?
LPS
HPS
MH
MV
QH+PAR
Incand
Fluor
Sports
LPS26 million lumens
HPS35 millionlumens
Metal halidesports
40 millionlumens
MHCommercial
8 millionlumens
LPS185 kW
HPS350 kW
Metal Halide sports430 kW
MHCommercial
130 kWMV
60 kW
Other white light Other white light 8 million lumens8 million lumens
117 million lumens117 million lumens 1.4 megawatts
Other white Other white light 200 light 200 kWkW
International Dark-Sky Assocation
Results: Where is Lighting Used?
Lighting and sky glow proportions
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Installed Effective Up (sports off) Up(sports on)
Municipal
RoadwaysResidential
Commercial
International Dark-Sky Assocation
Results: Where does uplight come from?
Sports lighting Sports lighting offoff
Sports lighting on
Munic+sports
Commercial
Roadways
Residential
Unshielded direct uplight
Commercial
Residential
RoadwaysMunic
Unshieldeddirect uplight
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
CONSTANTSFlagstaff Lighting and Land Use Project Population eff lm 50k eff lm 100k ave CU ave LLD ave LDD post-89 up fractEffective Maintained Lumen Values (mean lumens * CU * LDD) 55,000 #NAME? 44,200 0.65 0.8 0.85 0.05blue means linked to worksheets = update through worksheet, not here!
Total units Total acres Total acresON/OFF Summary Numberunits surveyedunit type mean lm/unitfactional err mean frac up frac err pre-89 50k 100k Total lm surveyed
1 Shopping Centers 9 101.56 acre 83971 0.08 0.03 0.36 172.64 12.26 8,716,4161 Auto Dealers 4 15.83 acre 39865 0.25 0.08 0.49 585,1881 C-Stores 3 3.00 each 224145 0.14 0.00 0.31 25 672,4341 Hotels 10 17.50 acre 83258 0.13 0.09 0.36 100.4762118 11.27 1,328,4521 Banks 2 2.72 acre 143875 0.34 0.01 0.42 347,6011 Restaurants 5 5.73 acre 164641 0.38 0.06 0.67 34.89367309 16.63 1.47 930,7171 Industrial 1 2.00 acre 30704 0.15 61,4071 Residential 115 115 each 541 0.08 0.38 13,000 62,2481 Apartments 3 274.00 each 2459 0.44 0.18 3,368 64.16 31.56 700,4101 Roadway Flagstaff 1 1.00 total 20,103,480 0.00 0.00 0.00 1 20,103,4801 Roadway Private 1 1.00 total 55,235 0.00 0.15 0.00 1 55,2351 Roadway ADOT 1 1.00 total 7,481,455 0.00 0.00 0.00 1 7,481,4551 Flagstaff Sports 1 1.00 total 25,481,221 0.00 0.13 0.00 1 25,481,2211 FUSD 1 1.00 total 0 0.00 #DIV/0! 0.00 1 01 FUSD Sports 1 1.00 total 8,478,750 0.00 0.13 0.00 1 8,478,7501 Flagstaff Muni 1 1.00 total 2,521,734 0.00 0.00 0.00 1 2,521,734
Total 77,526,747Total per capita 1409.577225
check these!Examine canopy impacts using AGI32 modelsGraph potential extrapolation methodsExtrapolate only unmeasured sites - directly enter measured sitesc-stores per unit, per acre and per pumpRe-do by using inventoried values then adding extrapolations…?check various commercial types - perhaps they are not all statistically different
cl to add cars
gen comm
warehouses