It wasn’t until my third year of college when I was 20 years old that I saw the Milky Way for the first time. I attended an intensive, 3-week ecology class that my school offered at a field station along Dennys Bay in Maine that was far away from city lights. For the final three weeks of August that year, I spent my days trudging through the nearby intertidal zones identifying plants and sea life, and my nights rushing through assignments so I could go out and enjoy the night sky. On one particularly clear night during the new moon, I found out there was an old telescope stashed in one of the storage buildings at the field station, and brought it out to an open field to try to get my first glimpse of the galaxies, nebulae, and other deep sky wonders I could never see from back home. When my professor walked past me on the way to his cabin, I mentioned to him that I may be too enthralled in the night sky to complete the reading assignment for the following day. I expected to receive something to the effect of a disapproving glare, but he instead responded by telling me that the library where he used to study had a sign above one of the doorways that read “Study Nature, Not Books,” and then walked away.
Since then, I’ve traveled to many dark places: Crater Lake National Park in Oregon, Joshua Tree National Park and Death Valley National Park in California, and the Adirondacks in New York, to name a few. Witnessing the night sky in those areas has made me realize just how dark and expansive the night sky can really be. However, the time I’ve spent traveling to these dark areas, as well as that field station on Dennys Bay, has taught me potentially how difficult it is for many of us to escape light pollution, and how many people have never seen the night sky at its full potential.
As an example of how light pollution affects our view of the night sky, take the image of the Milky Way posted above. I took this shot from the beach in Truro, Massachusetts near the tip of Cape Cod, looking to the southwest over the dark, undeveloped Cape Cod Bay. Regardless of how dark the bay was, the lights from the towns of Barnstable and Bourne, which lie 30 miles away from Truro, produced a yellow glow bright enough to spill into the core of the Milky Way and wash out some of its details. Even the porch lights from the rows of beach houses behind me were enough to ruin my view in the opposite direction. And for reference, a modern digital camera can pick up much more detail in the night sky than the human eye can, so without my DSLR gathering light from the night sky 20 seconds at a time, my view after letting my eyes adjust for a half hour looked more like the image below.
The unfortunate reality is that light pollution is a direct product of population density. Those of us who live near urban areas—or even suburban areas—run the risk of having our night skies obscured by the glow of excess light. When hoping to view or photograph the night sky, the most important thing to do is to put yourself in a dark location. However, as shown above, a dark sky overhead is not the only necessity. Light pollution from nearby—or not so nearby—cities and towns can spoil a dark sky in a given direction.
Nowadays, while planning out places to photograph the night sky, I regularly consult a light pollution map to help determine ideal locations for my shots. I live under the light-polluted skies of eastern Massachusetts, which forces me to make drives a minimum of 2 to 3 hours long to even begin escaping the glow of nearby cities and towns. Although there are a few different options available, the map I typically reference is found at Dark Site Finder or within the Android app “Plan It! For Photographers”, which each overlay light pollution data onto Google Maps with a 15-color scale. Other maps I have seen use a 9-color scale—which is based on the Bortle Dark Sky Scale—or actual satellite photos taken at night to show the glow of artificial light, but my preference is the 15-color scale because of the extra nuance it provides. For reference, the Bortle Scale ranges from 1 (Excellent Dark Sky Site) to 9 (Inner-City Sky).
For the purposes of photographing the Milky Way near eastern Massachusetts, I’ve personally found the darkest skies when heading towards the Atlantic coast. I can find beaches within about 2 or 3 hours of the Boston area that have reasonably dark skies overhead (typically about a “4 – Rural/Suburban Sky” on the Bortle Scale) with little to no light pollution out over the open ocean. When heading inland, I can still normally get to what the Bortle Scale considers a “Rural/Suburban Sky”, but with a higher risk of nearby light pollution spilling into the image. As a rough rule, even under a dark sky, I try not to have my camera pointed towards a large town within about 20 miles, and, in a perfect world, I try to keep 40 or even 50 miles away from cities such as Portland, Maine. When driving through western California years ago, I noticed that even from 80 miles away, there was an unmistakable dome of light emanating from Las Vegas, which should probably be a 10 on the 9-level Bortle Scale given the grotesque amount of light it spews in all directions.
If fully escaping light pollution isn’t a possibility, there’s still hope to see a dark view of the night sky. Driving or hiking to higher elevations can serve as another way to distance yourself from bright cities and towns. Further, at high elevations the possibility exists for a low layer of clouds to block light from spilling into the night sky. Lastly, if elevation isn’t a possibility, placing a mountain in between you and light pollution could also help to block excess light.
For the United States and other mid-latitudes in the Northern Hemisphere, the center of the Milky Way is visible from February to October each year, with the season varying the more one travels south. For those like myself in the United States, now is the time of year when the core of our galaxy starts to rotate into view in the pre-dawn hours just before sunrise. For photographers looking to get a shot of the Milky Way, now is the time to start planning and determining how far you may need to travel, if at all, to find a sufficiently dark sky. Similarly, those who have never had the chance to see the Milky Way with your own eyes, plan a trip this coming year during a new moon, go somewhere dark, look up, and enjoy.