Skymonitor Project Brings Dark Sky Issues to Light

light pollution US map full size
by Tara Laskowski. Mason Spirit, April 20,2012

Many major telescopes around the world are located in densely populated areas. Even Mason’s telescope, installed last year, is situated in the heart of Northern Virginia and only miles from the nation’s capital. With so much population, infrastructure and business, one may wonder how even the most powerful of telescopes can compete with the light pollution generated by all this activity.

Enter the SKYMONITOR project. Mason has joined this international initiative that will help to track and map the brightness of the night sky around the world. Supported by the International Dark-Sky Association (IDA), the National Science Foundation and the Vatican Observatory, the project will provide continuous, long-term measurements on the state of the night sky.

“There is an extended light-pollution problem as cities and suburbs grow,” says Harold Geller, associate professor in the School of Physics, Astronomy and Computational Sciences and Mason’s observatory director. “We are in a light-polluted area here in Northern Virginia, and it does affect what people can see in the night sky.”

Bob Parks, executive director of IDA, says that “sky glow” has interfered with astronomers’ jobs to such a large extent that many of them are moving out of the continental United States. And the problem doesn’t just  affect scientists. Wasted light contributes to economic issues and changes animal behavior, habitation and hunting patterns. “Light pollution is one of the few ecological issues that can easily be reversed, except that most people aren’t even aware of the problem,” Parks says.

Monitoring unit

A photometer like this one is installed on the observatory tower on Mason’s Fairfax Campus. IDA image

Estimates show that nearly $2.2 billion is wasted annually in the United States on light that shines into the sky and does nothing for safety, Parks says. “Fifty years ago, we used to be able to go out into our backyards and see thousands of stars. Now, you probably have to drive many miles to get to an area where there is enough darkness to see that. Seventy-five percent of the population will never see the Milky Way. We are depriving a whole generation of the ability to look up at the sky and be humbled by how vast our universe is,” Parks says.

The sky monitoring project will look at how artificial sky brightness varies geographically and how it changes over time. Geller explains that poorly aimed light limits what we can see in space — if the object you want to look at is only as bright as the sky, then you cannot see it. This is why we do not see the moon or stars during daylight hours.

To participate in the project, Geller has installed a solar-powered, calibrated photometer on the observation tower on the Fairfax Campus. The photometer operates nearly completely on its own. The data collected in Fairfax is transmitted to the IDA headquarters in Tucson, Ariz., where it will be archived and made available online to the public. The data recorded can be seen at:

Mason is one of 25 participating institutions. Others include Apache Point, Cerro Tololo Inter-American, Lowell, McDonald, Siding Spring, Kitt Peak, VATT, Palomar and Whipple observatories. The project hopes to eventually include many more sites around the world, such as “astronomical observatories, dark-sky preserves, national parks and other environmentally sensitive sites needing dark sky protection,” according to the website.

Write to Tara Laskowski at