Light pollution : A problem for humanity

International Dark-Sky Assocation

Light pollution : A problem for humanity

Donald R. DavisInternational Dark-

sky Association8 June, 2004


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


Startling fact:

Two thirds of the US population cannot see the Milky Way with the unaided eye from their back yards.

Why not?



Light pollution has negative effects on:

• Wildlife.• Environment.• Landscape.• Human Activities.


The Earth is really bright!




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.


IDA Statistics

• Total Members — nearly 11,000• Organizational Members — 569• Lifetime Members — 203• Newsletters Issued — 57• Information Sheets Published —

193




Bottom Line:

• Environmentally responsible,• Economically sensible.• Good lighting has great value!• We all win!


"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


Sky Brightness Measurement

Examples of Existing Programs

1)The National Park Service Night Sky Project.

2) Sky Brightness mined from an automated search program.


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




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


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


System Images

• 1024^2 px• 16 bit• 50 arcmin• 191 sec int• FITS format• clear channel• standard 2x2-in filters

G NA T


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.


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.


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.




• 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 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.


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


IDA award: International Dark Sky City


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?


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


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


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


Data Collection: Residential survey form


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


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


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


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.


Sky brightness changes since 1975


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

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Light pollution : A problem for humanity