Light Pollution: a Primer

The basic problem: Sky Glow Light from fixtures reflects off particles in the sky— ”Sky Glow.” Large cities visible from tens of miles. The stars are not brighter here in the country—the sky is darker!

The Global Problem

Light “Made in the USA”

What’s Wrong With this Picture?

Boone, 35 years ago…

… today

Even at Kitt Peak

Charlotte… Courtesy Spencer Rackley

Where does the sky glow come from ? Poor fixture design Lack of shielding Over-lighting Poor installation Market pressure

Floodlights Almost horizontal No shielding At night …

Floodlight used in ATMs Glare! Could you see a criminal? … He can see you…

Better: Full Cut Off (FCO) “Shoebox” design Why do you think they are chosen? … Appearance in the daytime! At night …

Burger King, Tucson

Even Better! Van Gogh’s Café Terrace at Night,1888 Experience at Tweetsie. Result from California study: reduce glare and you can reduce the overall lighting level

Sidewalk Lighting Post-top fixtures like these here on campus are often very glaring… … there is more to lighting than just foot-candles!

Billboards: the Bad Way Uplighted Most light reflected into the sky Often on all night

Roadway lighting: overhead glare

Cobra heads Filament below reflector Glaring to driver Light polluting

Better, FCO Fixtures No light above horizon Non-glaring to drivers, too! May require more poles per mile At night …

“Security” Lighting “Dusk-to-dawn” Security or lighthouse? Refractor very glaring and light polluting Frequent light trespass and neighbor problem Installed by amateurs and utilities

The Glare at Night (From High, Too!)

Solution: Sky Cap GE SkyGard shown Hubbell available Total FCO See results …

The Capped Light at Night

The Data

Private Security Lights

This “1973” shot impossible today! “Space Jam”

Car Sales Lots Often grossly overlit This one at Fc on lot, 65 on road Use astronomically unfriendly metal halides Can use sodium with 10% while to get color rendition

Wall Packs One of the worst fixtures for pollution as well as glare Are available in FCO What is the point of these? 

Sports Lighting Usually done poorly with lots of light pollution and light trespass. Can be done well as shown here, using fixtures like ….

… Musco fixtures Costs ~$100/fixture

Gas Station Canopies

Compare to This This station ~ 35fc Large diffusers easy on the eyes Easy on the camera, too…

How You Can Help Look at your own lights–are they needed? Could you have it capped? Put it on a switch, timer or a motion sensor. Put in a lower wattage bulb. Where do you eat out? Do the restaurants have glaring lights? If so, complain! … Are there some roadside lights that bother you as you try to drive? Complain!

Is there a street light that shines into your window at night? Call up the utility and ask for them to put a sky cap on it. Don’t settle for simple spray painting of the fixture’s lens! Write letters to your newspaper…. Teach your friends about good and bad lighting–point it out when you are out with them at night. (Spoil their view…)

Make a difference! Start a project to get owners of “security” lights to have sky caps installed on them. Spend some time at and become (more of) an expert! Join the IDA. Realize that you are the ones with rights to speak for (“pursuit of Happiness” [Dec.Ind., par.2]). Develop a local ordinance.

Concluding… Like the background on this presentation, let’s make the orange glow of sodium vapor go away.