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Educational Bulletin #13-1A publication of the Desert Protective Council protectdeserts.org

The night sky in the desert is a treasure to

behold, and on a clear night it is possible or a

city dweller to become lost in a twinkling sea

o stars. Faint meteors and constellations seem

to continuously emerge rom light years away

until it seems there is no more darkness let. A dazzling dis-

play o stars in the night sky is a resource visitors to the des-

ert oten expect and take or granted. Light pollution has

invaded the night sky, much like urban sprawl enguls our

wildlands, although there are simple steps each o us can

take to solve the problem o light pollution.

Measuring a Good Night Sky

A good night sky with minimal or no light pollution

will display a bright Milky Way, meteorites that would

otherwise not be visible i competing with city lights, dark

nebulae in the Milky Way are easily visible with binoculars

or telescopes, and the starry sky alone (no moon) wil l cast

noticeable shadows on the ground, according to the Inter-

national Dark Sky Association.

In an excellent night sky, a galaxy known as M33,

almost 3 million light years rom Earth, is visible to the naked

eye as a blurry cluster. In an excellent night sky, Jupiter and

Night Skyby Shaun Gonzales

A February starry night sky just west of Clark Mountain, with a Joshua Tree in the foreground. Photo by Shaun Gonzales

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Venus can shine so brightly that it is best not to stare at

them to preserve your eyes adaptation to the dark. Once

you are in the suburbs, these planets might be one o the

ew objects youll be able to see, the Milky Way is barely

visible, i at all, and M33 is not visible. The quality o the

night sky is constantly akin to having a ull moon overhead.

Once youre in the city, even the stars that orm the more

popular constellation patterns are aint, or not visible.

Measuring the precise impact o light pollution and thevisibility o the stars involves complex evaluations, but the

end result is a standard known as the Bortle Dark-Sky scale,

with excellent skies graded as a one, and inner-city skies

graded as a nine. There is another ormula used to estimate

urban sky glow known as Walkers Law that uses popula-

tion o the urban center and distance rom the sky viewer.

Roughly speaking, Walkers Law nds that a town o 3,600

people just 6 miles rom the viewer will emit a sky glow

impacting visibility o stars up to 45 degrees rom the ho-

rizon. A city o 5.6 million people will distort that same

horizon rom over 120 miles away.

Places that have excellent night sky are, not surpris-

ingly, ar enough rom concentrations o human light

sources that drown out our stars. The night sky in the desert

oers remoteness and oten cloud-ree skies that avail the

cosmos to visitors. Despite appearing as vast and open

as outer space, our deserts however, have not escaped the

impacts o light pollution, and domes o light pollution

that are visible on the horizon even rom the remote cornerso the Mojave and Sonoran deserts. Although the sprawling

metropolises o Las Vegas and Los Angeles are major cul-

prits when it comes to deacing the night sky, even smaller

towns like Barstow and Joshua Tree emit enough light pol-

lution to have their own noticeable impact on the night sky

From Keys View in Joshua Tree National Park, a air-

ly severe light pollution dome will obscure the night

sky on the horizon. The light pollution is rom Los

Angeles, Palm Springs, Indio and the Coachella

Valley, but even the small town o Joshua Tree with a

This illustration demonstrates how the view of our night sky transitions from the inner city to rural locations and then remote wildlands.

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population o about 7,000 people casts a glow that reaches

almost 20 degrees on the horizon, according to the Morongo

Basin Dark Sky Alliance. Even in the Pinto Basin, which

is urther east, the small town o Joshua Tree and the

Twentynine Palms Marine base produce a glow that

obscures the night sky stretching 20 degrees into the sky

rom the horizon.

Treasuring the Night SkyThe night skys most signicant and unquantiable

value to the average person who can look up and mar-vel at the starsis a humbling experience that inundates

a viewer with the immensity o the universe. Most city-

dwellers do not get to experience this unless they venture

into the desert. Todd Gonzales, an outreach supervisor at

Lowell Observatory in Flagsta, Arizona, highlighted the

surprise some Los Angelenos expressed ater looking up at the

night sky ollowing the 1994 Northridge earthquake, which

led to massive power outages. As a result o reduced light

pollution, some residents called local authorities to

report a strange silver glow in the night sky that they did no

recognize the Milky Way.

From an economic standpoint, night sky resources not

only sustain travel plans by those who appreciate a beauti-ul night sky, but they can also sustain astronomers. Ari-

zona is home to some o the stricter light pollution control

standards an eort to keep astronomers rom leaving the

state. From Lowell Observatorys perch above Flagsta

high power telescopes can study ar away stars and galax-

ies thanks to Flagsta s city code that keeps light pollution

to a minimum. The Observatory built the new Discovery

Channel telescope south o Flagsta, and rom there the

light dome o Phoenix is visible on the horizon. In an eort

to keep millions o dollars o investment in astronomy re-

search and telescope construction rom feeing the state, theGovernor o Arizona in 2012 vetoed a bill that would have

permitted bright electronic billboards in the state.

To wildlie, the night sky has a much more signicant

value. Some animals use the moons polarized light or

navigation, but the addition o light pollution conuses

JOSHUA TREE NATIONAL PARK

NIGHT SKY / LIGHT POLLUTION

KEYS VIEW

COACHELLA VALLEY

INDIO LA QUINTA

PALM DESERT RANCHO MIRAGE

CATHEDRAL CITY

PALM SPRINGS

LOS ANGELES

YUCCA VALLEY

JOSHUA TREE29 PALMS

TWENTYNINE PALMS MARINE BASELAS VEGAS, NEVADA

EL CENTRAL IMPERIAL

COACHELLA VALLEY

DATA COLLECTED 09/25/2008DATA SET COLLECTED BY:Luke Sabala Physical ScientistDon Duracua Physical ScientistImage by Luke Sabala Physical Scientist

80

60

40

20

0

180 210 240 270 300 330 0 30 60 80 120 150 180

Poor lighting wastes energy to the tune of $2.2 billion

per year in the U.S. alone.

International Dark Sky Association

www.darksky.org

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wildlie that are accustomed to using the moon to navigate.

Lit buildings in the city, or example, oten conuse migrat-

ing birds, and lead to deadly collisions. Thousands o birds

migrate each year through our southwestern deserts to and

rom Latin America. Frogs, toads, and salamanders are es-

pecially sensitive to articial light, and in the desert riparian

areas they would have little or no options or relocation.

Insect swarms attracted to articial light can also lead to

ecological imbalances in the relationship between preda-tor and prey. Bird and bats that are not repelled by articial

light begin to gravitate toward these insect swarms, while

predators that avoid articial light such as some species

o bats suddenly lose access to much o their ood source.

Fixing the Night SkyReducing light pollution primarily depends on careul

lighting design and selection, using shielding that ocuses

lights downward and limiting brightness when possible.

Streetlights, without cutos or appropriate shielding, emit

what is known as ugitive light light that does not con-

tribute to lighting the street. The same can be the case or an

outdoor security light at your house, or lights on billboards

and parking lots. All o this adds to light pollution, but a x

can be simple and add to your energy eciency.

Light pollution is a symbol o waste. Excess light sent ar into

the atmosphere does not serve the lights intended purpose,whether it is to keep a parking lot, ront porch, or a billboard

lit. It is estimated that the United States alone projects near-

ly 4.5 billion dollars worth o light into the atmosphere, each

year. As we tackle ossil uel use and climate change, this

lack o eciency is startling, and addressing light pollution

has the positive side-eect o reducing our dependence on

centralized power plants that oten destroy the same wild-

lands we cherish.

So what can we do? For your porch light or outdoor se-

curity light, you can replace unnecessarily bright bulbs with

a lower wattage LED bulb that is shielded youll be able

to light up your entryway without competing with a galaxy

millions o miles away.The Morongo Basin Dark Sky Alliance has begun a bulb

exchange, and plans to replace 50 lights in the Joshua Tree

area beore the end o the year. According to Victoria Fuller

the Alliance is replacing less ecient lights with nine-watt

LED bulbs, and educating the community about proper

shielding. Victoria noted that the Alliances eorts have also

served as an excellent opportunity to orm alliances, work-

ing with the nearby Marine Corps base and the Nationa

Parks Conservation Association. The Alliance is hoping to

change San Bernardino Countys ordinances or the desert

area to limit light pollution.

Without these measures we are missing out on a beauti-

ul scene that can be available to us every night. A starry

sky that wildlie depends upon; natures own high denition

television, with three dimensional programming running

rom sunset to sunrise or the weary desert traveler.

Shaun Gonzales describes himself as a desert activist who

grew up in Victorville, CA. The Desert Protective Council is

grateful for Shauns voice and his sharing of desert knowledge.

Morongo Basin Dark Skies Alliance; educating the public about wha

we can each do to help keep our night skies.

Photo courtesy of Morongo Basin Dark Skies Alliance.