By Chris Fellows, Serenity Mobile Observatory
Embrace the Darkside
For those of you who follow me on my Facebook page, you already know that I have been frustrated over the last month by the terrible light pollution in Yuma, Ariz. I complained with almost every post about my inability to see even the brightest of celestial objects and the disappointing views my visitors were getting at the eyepiece. Now that I have moved to a much nicer location near Quartzsite, Ariz., I thought it was time to talk about this issue and provide some resources that you can use to avoid this problem.
Throughout human history the night sky has been a source of wonder and beauty to every human society. Early humans used the stars to inform them about the world we live in, when to plant crops, when the herds were coming, where we were in the world and what direction to go. Many, if not most, of the stories and legends handed down from our ancestors were immortalized in the picture book of patterns in the starry firmament we call constellations.
Only in the last century, with the development and proliferation of electric lighting, did we turn our heads away from the sky and towards our technology. Gradually we added more and more artificial glare and the sky began to fade from memory. Today, especially in urban areas, the splendor and majesty of the heavens is all but lost. The sky has turned into brownish grey mud where you can only vaguely see a handful of the brightest stars. Nowadays you must journey far away from populated areas to get even a mediocre glimpse of the grandeur of the heavens. In this article I am going to tell you how to find these ever-shrinking spots and provide some resources that can help stem the tide and in some cases even reverse this blight on our collective consciousness.
First, let’s take a look at the problem in a more measurable way. Astronomers have noticed this problem since its very beginning – even a little light pollution can greatly diminish one’s ability to see faint diffuse objects such as nebula and galaxies through a telescope. Astronomers use a well-defined magnitude scale to measure the brightness of celestial objects. It is complicated, not intuitive, and varies from observer to observer when making non-measured estimations of the overall darkness in a particular location.
In 2001, in Sky and Telescope magazine, John E. Bortle, an amateur astronomer and comet hunter, developed a scale that anyone can use to classify the darkness of the sky over their head. Now known simply as the Bortle scale, this tool rates naked eye skies on a simple 9 level scale from 1, excellent dark sky, to 9, inner city sky. This is the scale I use when I describe the sky to my astronomer friends. With this single number an experienced observer can know what to expect to see when they look up.
With that in hand, we can now use another useful tool to find good observing sites around the country. Although there are several sites on the internet that allow you to do similar tasks, I like Dark Sky Finder. On this site you can get an interactive map of the entire world that rates the sky down to a mile or two on the Bortle scale. When planning my stops, I always use this map as a weighing factor to decide on a particular destination. The National Park Service (NPS) also provides an excellent resource for finding camping locations under night skies. If you are planning on visiting one of our national parks I highly recommend visiting this site.
How can you make sure you are not “part of the problem”? As a general rule of thumb, only use light that is absolutely necessary. Why put in a 1500-watt halogen flood light when a 5-watt LED would be plenty to light your path to the driveway? Why put up an unshaded omnidirectional sodium vapor glare bomb when a downward-directed task light will get the job done? As Americans we tend to think that bigger, stronger and brighter is better. Advertisers boast about the power of their products and something way down deep in our lizard brain does the Tim Allen “Whoa-ho-ho, I need me one of those!”
But do you really? I have visited Mammoth Cave National Park many times and taken all of their tours. One of my favorite parts of the tour is when the park ranger takes you into a cavernous room the size of a sports arena and turns off the lights. It is pitch black – you can’t see your hand an inch from your nose. After a minute of this you can feel the tension in the room start to climb. The ranger speaks in soft, reassuring tones and just as the collective consciousness of the group is about to snap, the ranger lights a single match.
That tiny spark of light illuminates the entire room, even yards away you can easily make out the people standing around you. At this point people stop holding their breath and some will even laugh nervously as the stress ebbs from their bodies. The point is, that even a tiny light can get the job done, so when making lighting decisions always lean towards “less is more.” The International Dark Sky Association (IDA) has many more suggestions and recommendations, including product recommendations to help you help the sky.
Well, this article is running a little long so I will get off my soapbox now. I hope this will help you find some gorgeous dark skies on your travels and make good lighting decisions. Until next time…
Chris Fellows, Serenity Mobile Observatory
Find Chris on Facebook (or, if you’re lucky, at your campground). (Editor: Check out his amazing photos on his Facebook page!)