Data shows dark skies over Mojave Trails National Monument


The Mojave Trails National Monument could qualify as an International Dark Sky Sanctuary, according to new data released Tuesday by the Mojave Desert Land Trust.

The 1.6 million acre monument borders Joshua Tree National Park to the south and partially surrounds the Mojave National Preserve.

Interns from the Mojave Desert Land Trust’s Women in Science Discovering Our Mojave (WISDOM) program recently completed a year-long study measuring the brightness of the sky at 16 locations on the monument.

Collecting the data was the first step in the Bureau of Land Management’s efforts to achieve Dark Sky Sanctuary status for the monument. An official request has yet to be submitted to the International Dark Sky Association, which recognizes communities, parks and protected areas with dark skies.

“We appreciate the studies carried out by our partners at the Mojave Desert Land Trust regarding the potential for a Dark Skies sanctuary designation in the Mojave Trails National Monument. Although this is early in the process, we will continue to work with the MDLT to discuss a potential application to the International Dark Skies Association, ”the California State Office of Land Management said in an emailed statement.

In order to qualify for Dark Sky Sanctuary status, light readings must regularly be equal to or greater than 21.5 magnitudes per square arc second. A measurement of 21 indicates a very dark site, and a measurement of 16 indicates a light polluted site.

The data collected shows that the Mojave Trails National Monument is eligible to apply for International Dark Sky Sanctuary status, as the average measurements at almost all of the monument’s locations are above 21.5.

The darkest point of the monument was measured at Camp Iron Mountain and the brightest point is in the Sheephole Valley wilderness area. The eastern half of the monument is generally darker than the west side, which is more easily accessible to visitors and includes the Afton Canyon Natural Area, which is home to the only developed campground in the monument.

But even the Afton Canyon area measured 21.1 magnitudes per arc second and “still offers exceptional night sky quality,” according to the Mojave Desert Land Trust.

A map showing Sky Quality Meter Light measurements for various locations in the Mojave Trails National Monument.  The darkest place is at Iron Mountain.

“Thanks to the research of the WISDOM interns, we now have basic data confirming the premise that the Mojave Trails National Monument has some of the darkest skies in Southern California. Establishing the monument as a Dark Sky Sanctuary would mean protecting and conserving the region’s night skies, while also providing information on their importance to the flora and fauna of the desert, ”said Michael Mora, director of public awareness and engagement at MDLT.

In addition to providing stargazing opportunities for humans, the dark skies also have an impact on desert animals – artificial lighting can impact species migration patterns, predator-prey relationships, and animals. circadian rhythms.

According to the International Dark Sky Association, dark sky shrines must be legally protected public or private land and partially or fully accessible to the public. Sanctuaries are usually found in very remote locations, such as Cosmic Campground in the Gila National Forest in western New Mexico or Great Barrier Island, located 62 miles northeast of Auckland, New Zealand.

The International Dark Sky Association also recognizes Dark Sky Parks and Dark Sky Communities. Locally, Joshua Tree National Park is a dark sky park and Borrego Springs is a dark sky community.

Dark Sky Parks must also be legally protected public or private land and at least partially accessible to the public, with a night sky brightness that is consistently equal to or less than 21.2 magnitudes per square arc second, slightly greater than threshold of 21.5 required. for Dark Sky Sanctuary status.

Dark Sky Communities must be a city, municipality or other legally organized community that has implemented an “ordinance on quality outdoor lighting, dark sky education and citizen support in dark skies,” according to the ‘International Dark Sky Association. There is no brightness requirement for Dark Sky communities.

The process to receive recognition takes between one and three years.

Erin Rode covers the environment for the Desert Sun. Contact her at or on Twitter at @RodeErin.


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