The night sky
Updated: Aug 9
One of the Great Natural Wonders
The night sky is one of the great natural wonders. We in northern Arizona are fortunate to be able to enjoy it in a nearly pristine state. Fewer and fewer people have this privilege. According to a study published in the journal Science Advances , 80% of people living in North America cannot see the Milky Way from where they live. The residents of Flagstaff and the surrounding areas are among the lucky few who can not only see the Milky Way, but see it with clarity. We can do this largely because the residents of this area have a long tradition of protecting a dark, natural sky, relatively untainted by artificial lights. In Flagstaff’s early days it was nicknamed the skylight city. Flagstaff is also the world’s first international dark sky city, as designated by the International Dark-Sky Association in 2001. The city’s practices to preserve the natural sky have long served as a model for communities all over the world that also value natural skies. Coconino County also has similar protections to maintain a natural sky.
The preservation of a natural sky has many benefits. A major one is to astronomical research, which can only be done with something close to a natural sky. Arizona has more observatories than any other state. Northern Arizona is home to both Lowell Observatory and the Flagstaff branch of the U.S. Naval Observatory. Lowell Observatory has been at the forefront of astronomical research since its founding in 1894. Pluto was discovered at Lowell Observatory by Clyde Tombaugh in 1930, the first evidence that the universe is expanding was discovered at Lowell Observatory by V.M. Slipher in 1912, and Lowell Observatory played a key role in creating the maps of the Moon that were used to plan the first Moon landings. Lowell Observatory continues to do cutting edge research on everything from the planet Mars to distant galaxies. The U.S. Naval Observatory opened a station in Flagstaff in 1955. This observatory specializes in accurately measuring star positions, research that has wide ranging applications in both military and civilian technology. Pluto’s largest moon, Charon, was also discovered by Jim Christy in 1978, using photographs taken from the Flagstaffbranch of the Naval Observatory. These institutions bring millions of dollars a year into northern Arizona’s economy, and the research they perform is something all residents of the area can be proud of.
A natural sky has other advantages as well. Maintaining a natural sky helps preserve natural ecosystems. Animals use the natural night sky for navigation, to hide or to hunt, to know when to sleep or to be active, even to navigate. Virtually all animals use the cycle of day and night in some way or another, and so having a night sky that is bright with artificial lights can interfere with local ecosystems in countless ways.
Maintaining a natural sky does not mean that we have to live in darkness. By using light thoughtfully, we can maintain a natural sky while actually having better ground level lighting than we might have had otherwise. Better lighting efficiency can lead to lower energy bills as well. Dark skies does not mean dark grounds! Here are some of the things you can do to help preserve a natural, starlit sky for yourself and your community:
Make sure that lights are shielded in such a way that the light from them points down towards the ground. Light that goes straight up degrades the natural sky without providing any benefit to ground level visibility. Shielding lights so that illumination is directed downwards increases the efficiency of the light, helps preserve a natural sky, and actually improves lighting and visibility on the ground.
Don’t use brighter lighting than is needed. It’s a misconception that more light automatically means better visibility. Think of the last time you looked into car headlights with the brights on. The glare from bright lights, even from something lit indirectly, can make it much harder to see anything else. Avoiding excessively bright lighting not only helps preserve a natural sky, it can drastically improve ground level visibility and safety.
It matters what color lighting you use. The eyes of humans and most animals are impacted much more strongly by blue light than by red or orange lights. The LEDs that are used in most modern lights usually emit disproportionately blue light. However, it’s not hard to obtain LEDs that have been modified to emit light richer in reds and oranges. The packaging for most LEDs should indicate what temperature the light from the LED emulates. The International Dark-Sky Association recommends LEDs that emulate a temperature of less than 3,000 K (lower temperature means more reds and fewer blues). These kinds of lights are much more animal friendly, will make things more visible with less light, and will give things a more color rich and natural appearance as well.
Turn off lights when they’re not needed, or attach them to motion sensors, so they’ll only be lit when there are people nearby who need them.
Talk to your friends and neighbors about the value of a natural sky. The more of us that act to preserve a natural sky, the better all of us will be able to enjoy it.
Enjoy the night sky, especially with friends and family. We’re extraordinarily fortunate to live in a place where so many of the sky’s wonders are easily visible. On a clear and moonless night, away from any artificial lights, you’ll be amazed by what you can see with just your eyes, and even simple binoculars will unlock even more wonders. The more in touch we are with the sky, the more in touch we are with the universe, and the more we realize what we lose if we lose the natural sky.
The natural night sky is a birthright of all people, and its protection is a cherished tradition in northern Arizona. If we work together, we can preserve the wonder and beauty of the natural night sky for ourselves, our friends and families, and generations to come.