Light Pollution – Losing our Night Skies
On December 23rd, 2014, I visited a new dark site that I’d scouted out the previous week in order to get the necessary exposures for an image of Orion’s Sword. It was the first time I’d been to a dark site since early summer, and back then I was too green to know how to make use of those dark skies. I was also plagued by issues with an untuned mount and limited knowledge of how to properly guide to get the best performance out of my equipment. As such, this was my first true dark site visit, and quite a successful one at that.
Why did I visit a “dark site”? Because of light pollution, another form of pollution that most people don’t generally recognize as pollution, but which has become an increasing problem in recent years, and is accelerating…with potential dire side effects for both wildlife and people. Light pollution also makes it very difficult to effectively photograph the night sky. For every photon collected from some deep sky object, dozens, maybe even hundreds, are collected of reflected city light that bounces off the atmosphere and atmospheric particulates.
Dark skies. The holy grail of any astrophotographer…truly dark skies. They are a rare commodity in the modern age. We humans pollute the night skies with ever increasing volumes of artificial light…so much light that our cities are brilliant beacons to external viewers, as evidenced by the time lapse videos taken by astronauts on the ISS:
In one sense, our use of electricity to illuminate the night sky produces incredible beauty, as seen in the video above. On the other hand, it has blocked the beauty and brilliance of the night sky, of the Milky Way and everything within it, from view of most people within 40-50 miles of any city. Finding decently dark skies can be difficult, especially those within reach. Truly dark skies can’t be found closer than about 100 miles of major population centers, and reasonably dark skies can’t be found closer than about 60 miles.
When you see the night sky from an extremely dark site, without the intrusion of city light pollution bubbles on the horizon, with fully dark adjusted eyes…it is a truly amazing sight! I remember seeing the Milky Way when I was younger, but it’s been so many years since I have had the chance to really go far from the huge Denver metro area that I’d almost forgotten what a sight it could be. Even during my childhood, I’d only ever seen the milky way faintly, veiled by a veneer of atmospheric particulate reflecting all the light we generate at night. During this summer, I headed out about 70-80 miles from my home…past Kiowa on Highway 86 here in Colorado, and saw the milky way under some extremely dark skies…and it was quite a thing to behold.
I don’t know that, until that moment, that I had ever seen the Milky Way in such brilliance and detail. The galactic core was so bright that the arms of dust that reach out into Scorpius were clearly visible, what we call “The Dark River”, were shading the dense pack of stars behind. Several nebula around the galactic core were visible to the naked eye, as were a number of other deep sky objects, including galaxies and star clusters. It was one of the most amazing things I’d ever seen, and made me realize how much light pollution there truly was along the Colorado front range. I’d forgotten what the night sky looked like…how sad. How many other people had forgotten? Worse, how many other people live in cities their whole lives and never even know?
Saving the Beauty of our Night Skies (and our health)
Recent studies have also shown that our extensive reliance on bright light to illuminate the night is having dire side effects for both wildlife and humans. The constant bombardment of light has contributed to an epidemic of sleeplessness in modern technologically advanced (western) societies, and has an impact on the circadian rhythms of wildlife and birds as well (a key example would be the American Robin, which under normal rural (dark sky) conditions will wake up and sing from just before dawn to just after, maybe an hour at most…yet which will wake up and sing from 2-3am and continue on well into the day, some all day and late into the night, when bathed in city light.) Light pollution has been increasing at a dramatic rate in the past decade. Europe is plastered in light, and the eastern half of the United States is also covered in it:
The western United States has less of a light pollution problem, however within the last couple of years, the amount of light pollution from the Denver (and generally, the entire front range) has increased considerably. The Denver metro area has brightened by a factor of two since the beginning of 2012. Similar increases were seen in other major population centers within the midwest and west. Europe has seen a convergence of light pollution bubbles, creating huge regions where the brightest stars of the major constellations can barely be seen, and no nebula or galaxies or star clusters or any of the other amazing things within our night skies can be seen.
We are losing our natural night, in some places we have already lost it. At the very least, many people rarely or never see the night sky for what it is…in all it’s wonderful, expansive, infinite beauty. At the very worst, it could be affecting our health by blocking natural cycles from occurring. Both humanity and wildlife are being affected by the constant bombardment of artificial light, which prevents our bodies natural responses to sunlight, moonlight, and the extremely faint starlight, from functioning correctly…and in some cases may even lead to worse diseases, like cancer, depression, etc. (see: http://darksky.org/further-research/reports-studies). If you care about restoring our night skies, for your own sake, for your own viewing pleasure, for our future generations, please visit the International Dark Sky Association‘s web site, and learn what you can do to help. If you are a homeowner, you may be able to change the kind of lighting or light fixtures you use to reduce the amount of waste light that reaches the sky, reduce your reliance on lighting at night, and save on your energy bill. If you are a member of a city council or other political office, you may be able to use your position to influence future decisions regarding the use of artificial light in cities and metropolitan areas, and help guide such cities towards making choices for lighting infrastructure that can reduce the amount of light pollution created, or eliminate it entirely (which again, can save…potentially very significantly…on energy costs, which is another benefit for taxpayers at large.)
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