Measuring “skyglow” and understanding light pollution with the Dark Sky Meter
Citizen science after hours…here are some citizen science projects you can do at night.
See also our recent feature of Dark Sky Meter.
If you have ever seen a satellite photo of the eastern seaboard of the United States, taken at night, you will understand the term ‘light pollution.’ Poorly designed lights shine upward instead of downward and actually contaminate the sky with unnecessary light. Consider that as result of this there are people alive today who have never seen the Milky Way, not because they don’t look up, but simply because of this light pollution. (A Loss of the Night poll found that 13% of respondents have never seen the Milky Way.)
Besides having the potential to alter sleeping patterns of humans, light pollution interferes with bird migration, sea turtle reproduction and mammal feeding habits. When nocturnal birds fly through a brightly lit area, they become disoriented, and they will often crash into brilliantly lit towers or buildings, or circle around them until they fall exhausted to the ground. More than 450 bird species migrate at night, and according to a National Geographic article, over a period of two days, 50,000 birds died at Warner Robins Air Force Base, Georgia, in 1954, after they flew directly into lights on the ground. In 1981 more than 10,000 birds flew into the floodlit smokestacks of a power plant in Ontario, Canada. Light pollution is a modification no less extreme than fossil fuel emissions or the damming of a river, and while we all need water, transport and light, brightening an area can be achieved in a m ore efficient or human and wildlife-friendly manner.
Last year, out of his interest as an amateur astronomer, a Dutch programmer developed an app called Dark Sky Meter (official site). “I created the app, the backend, interfacing and storage services,” says Norbert Schmidt whose company also manages the data and supplies it to other scientific projects. Initially developed for personal use, the app’s traction has broadened substantially. Schmidt says, “There’s a lot of non-astronomical interest for the app, including from ecologists, environmentalists and even Islamists who want to measure periods of darkness.”
It’s still too early to publish significant findings since frequent app use only began in the fall of 2013, when darkness returned to the northern hemisphere. Since then however, 800 measurements were recorded in September, 1,500 in October, 3,000 in December, and 4,000 in February. “So it is rapidly increasing,” says Schmidt. The total number of app downloads now stands at around 5,000.
Somewhat incongruously Jean-Bernard Minster who serves as a Professor of Geophysics at the Scripps Institution of Oceanography is using the app for a purely personal reason. He lives alongside a large athletics arena where the nightlights are particularly troublesome. He says, “My interest is completely focused on local light pollution caused by an outdoors sports facility in my neighborhood.” Minster hopes to recruit about a dozen people in the neighborhood to help him collect data, and while he may publish, it will most likely be in the local newspaper.
Other scientists—for example those serving on the Globe at Night team, will use the data to examining actual sources of light pollution. Dr. Christopher Kyba, a postdoc at Leibniz-Institute of Freshwater Ecology and Inland Fisheries, and a guest researcher at the Institute for Space recently published results in the journal Nature Group following the Globe at Night project. “Many of the conclusions from that paper also hold for Dark Sky Meter, for example DSM data will be used to calibrate and test predictions of skyglow, and this type of data is invaluable for tracking global changes in skyglow.”
The Globe at Night paper focused on skyglow, and Kyba has only just begun work on analyzing the Dark Sky Meter data. DSM data serves as a source of information for projects like Globe at Night.
The Dark Sky Meter app is only available for the iPhone because there are so many Android models, and each phone has a different, uncalibrated camera. Minster says, “The iPhone implementation is a very logical choice, but the market is of course restricted. Perhaps if a user-run reliable calibration process can be devised, the App could be made available to a much larger base of data collectors. I would like this very much, because it would make light pollution a much more broadly understood issue.”
Norbert Schmidt planned Dark Sky Meter largely for amateur astronomers, but with Kyba organizing Night Sky Flashmobs to inform scientific research, and Minster rounding up the neighbors to form a lobby against a relatively underreported form of pollution, the app seems to be developing its own niche as the creator of a database of the darkest areas, and a live map of the best places to view the Milky Way .
Download the app here: http://www.darkskymeter.com
Globe at Night paper published in Nature:
http://www.nature.com/srep/2013/130516/srep01835/full/srep01835.html
Images: NASA, courtesy of Dark Sky Meter app
Ian Vorster has a MS in Environmental Communications and most recently served as director of communications at the Woods Hole Research Center in Massachusetts. Prior to that he worked in the health communications field. Ian has served as a designer, writer, photographer, editor and project leader in the field of science, and now works freelance in a blend of these roles.
