SDRP - Did You Know?

The San Dieguito River Park
18372 Sycamore Creek Rd.
Escondido, CA 92025
Phone: (858) 674-2270
Fax: (858) 674-2280

The River Park has converted from a print-based distribution system to a web-based system. If you are interested in receiving e-mail notices when the quarterly activity schedule is posted to the website, and news of special events occurring in the Park, click above to send us an e-mail.

DID YOU KNOW?
by Shawna Anderson
Fall 2005

DARK SKIES ENDANGERED

I remember as a girl growing up in San Diego looking up into the night sky to gaze at the stars. Those stars have slowly disappeared from view and these days one must travel further and further from the city lights to see stars. As governments and the citizens of San Diego invest to preserve the San Dieguito River Valley they consciously realize the benefits – an open space preserve absent of development, native habitat for animals and birds in constant competition for space and food, passive recreation, a bit of peace and quiet, and so on. There is also another benefit although maybe not as apparent – patches and ribbons of darkness. These areas are especially obvious when viewing satellite imagery, dark areas surrounded by a bright sea of lights – development. One of the benefits of these dark places is the ability to better observe the world outside our own, the cosmos.

Just like native habitats and wild rivers, our dark skies are a natural resource. This resource is mostly gone at least the way our ancestors saw it. Those who just wish to view a beautiful starry night, or to see the Milky Way or other fascinating objects in our universe, must travel long distances to get away to where the sky is dark. Increasingly the “urban sky glow” – or brightening of the sky from man-made lighting - has created a challenge for astronomers (both amateur and professional) to view the galaxies. Remote areas, away from cities where the sky glow is less, are where astronomers go to find some relief from the sky glow. Preserving the open space within the San Dieguito River Valley helps to reduce the impact of development on our night sky and provides areas of darkness where night light is absent. Without these dark areas, viewing the night sky would become almost impossible. This natural resource is vital to astronomy. Interest in astronomy is increasing as more technologically advanced telescopes are accessible to amateurs. As well, ground-based telescopes are still much more efficient than space-based and larger more advanced telescopes are allowing more information to be collected and analyzed from earth.

Everyone agrees that night lighting is necessary for security, safety, utility, and even aesthetics. A certain amount of sky glow or pollution must be expected with increasing development, however, much of the impact of night lighting is the result of poor night lighting that creates glare and unnecessarily lights the night sky as well as natural habitat. Poor night lighting includes lights that shine upward into the sky or unnecessary lights. There are several things we can all do to reduce poor lighting in our environment including use of low pressure sodium lamps, use time controls or motion sensors, use good quality shielded lights, and don’t overdo the light level – only light to a level that is necessary for you to see adequately. Some cities and counties have adopted light pollution ordinances, including the County of San Diego. And of course preserving areas of natural undeveloped open space like the San Dieguito River Park helps to reduce the threat to dark skies.

For more information about the effects of light pollution on night skies and to see examples of good and bad outdoor lighting fixtures see the International Dark Sky Association website at www.darksky.org.