Look up. Into the sky; into the stars. There is a vast universe out there, and thousands of astronomers throughout this planet are dedicated to discovering its secrets.
Tucson, Arizona is home to some of the most advancing astronomical technologies and highest visited astronomy viewing sites in the world. Many Tucsonans and travelers have visited local observatories, such as Kitt Peak and Mount Lemmon, and enjoyed immersing themselves in Tucson’s rich astronomical history.
Yet Tucson’s dark skies may fade away due to light pollution.
Buell Jannuzi, Ph.D., director of the Steward Observatory and Department of Astronomy at the University of Arizona (UA), is forced to deal with Tucson’s brighter skies from the center of the city and has been finding ways to decrease light pollution.
“What happens when you have lots of night at light is that the light scatters off the atmosphere and raises the background that you’re competing with when you’re trying to observe a faint galaxy or star – the same way with the sun in the daytime,” Jannuzi said. “The reason the sky is so blue and the sky is so bright is that light is being scattered off the atmosphere.”
Jannuzi’s Department of Astronomy and Steward Observatory focuses on astronomical research outside our solar system, encompassing everything from far-off galaxies to astrobiology to extreme astrophysics.
“When Steward Observatory was first started and we got our first research telescope in 1923, there was a cute letter where the first director of the observatory, Andrew Ellicott Douglass, complained that [the astronomers] needed the athletic lights to be turned off after hours so that it wouldn’t bother the observatory,” Jannuzi said. “So there’s always been a little bit of a struggle to try to protect the quality of the dark sky.”
“But people need light at night,” Jannuzi said. “So we try to encourage people to use the least amount of lights for their need, and to turn them off when they don’t need them.”
Lori Allen, Ph.D., director of the Kitt Peak National Observatory and associate director of the National Optical Astronomy Observatory (NOAO), is also concerned about how Tucson’s light pollution is affecting local observatories and utilizes city ordinances to prevent an increase in light pollution.
“Both Tucson and Pima County have adopted good outdoor lighting codes that require outdoor lighting to be within certain brightness limits and to be fully shielded, and that has allowed the observatories nearby at Kitt Peak and Mount Lemmon to continue operating,” Allen said. “Had they not made the effort to update those codes, we would probably not be able to have observatories near here.”
Allen has been the associate director of NOAO for seven years and has been the director of Kitt Peak National Observatory for three years. Among many of her obligations as director, Allen may attend zoning hearings that might convert an area near housing communities into commercial use or updating lighting codes with newer technologies. The meetings are just a portion of her concern on light pollution in Tucson.
“While there was a significant increase in sky brightness along the horizon, overhead the observatory is still dark,” Allen said. “And that says a lot about the city of Tucson and Pima County lighting codes. If you look at the sky above Tucson, it is still relatively dark. In contrast to that, in the direction of Phoenix, there is a very bright light dome, because they don’t have the codes that are quite as strict.”
Both Allen and Jannuzi agree that lights, such as streetlights, need to be updated.
“Right now there is a program with the city that is installing new street lights – they’re new LED street lights,” Jannuzi said. “They emit light over more wavelengths than the old high-and-low pressure sodium street lights – those lights basically emitted light at one wavelength of light; these emit over a broader wavelength. But they are cost effective for the city in terms of energy, long term they last a long time, and they can dim them.”
And along with the technical updates, Allen argues that the city should simply use less streetlights overall.
“You can drive around and find many parking lots around buildings of all kinds that are lit all night long, when there is absolutely no one around,” Allen said. “You need some amount for safety, you need it to be strategically placed, but you don’t have to light up an entire two-acre parking lot when there are no cars coming in and out.”
Using light requires electricity, which comes from energy, which requires resources like coal, solar, or water. Think of light as a resource that needs to be managed, and as something that humans potentially need to conserve for the long-term.
“Nobody in Tucson would ever turn on their garden hose and let it run all night long into the street,” Allen said. “And that’s literally what we’re doing in the city when we leave lights running all night long.”
Joe Frannea is the Southern Arizona chapter leader of the International Dark Skies Association (IDA), and he and the IDA work to educate locals on dark skies and their importance.
“They’ve been really quite effective,” Frannea said. “They just try to educate and understand and try to show a better way to do things, and eventually things will get done.”
The mission of the IDA, according to their website, is to “protect the night skies for present and future generations.” The IDA has campaigned to protect dark skies worldwide and educates individuals on “the negative impacts of artificial light at night on human health, wildlife, and climate change.”
Studies completed by the IDA have shown that artificial lighting at night effects the reproduction cycle of frogs and toads by disrupting nighttime mating rituals, as well as coral reefs, which spawn new life by moonlight. Nocturnal birds often collide with illuminated buildings when they fly towards an artificial light, and baby sea turtles also wander off course when they follow the light towards artificial lights, instead of the ocean’s horizon.
“People are totally oblivious that there’s any possible harm by having outdoor lights at night to our wildlife,” Frannea said.
The IDA has also completed studies that show human health is impacted by artificial lighting. It disrupts human biological clocks for day/night cycles, impairs vision with glares, and there are ongoing studies linking cancer and artificial lighting, among other health impacts.
“Our goal is to utilize smarter lighting wherever we can, and the good news about all of that is that lighting that is dark skies friendly is also healthier for humans and wildlife, is more energy efficient, will save money over the long term, and is really a win-win-win situation,” Allen said.
More good news can be found in the economic benefits that astronomy brings to the state of Arizona.
“It’s important to note that astronomy is actually a big industry in the state of Arizona,” Allen said. “The astronomy is responsible for pumping at least a quarter of a million dollars a year into the Arizona state economy. And it’s a clean industry; it’s an industry that provides high-tech jobs to people in the state, and it’s an industry that I think most Arizonans are very proud of. And if we are able to keep the skies dark, then we will be able to keep this industry in Arizona indefinitely.”
With the help of individuals like Allen, Jannuzi, and Frannea, Tucson’s dark skies have a “bright” future.
“Appreciate the night sky,” Jannuzi said. “We are fortunate to live in a part of the world that is beautiful both in the day and night, and it’s a part of our cultural heritage to be able to enjoy the desert night skies.”
“A good rule for people who drive around at night and wonder about lighting codes: If it’s friendly for your eye, chances are it is dark skies friendly,” Allen said.
This article was originally written in the fall of 2016.
Thank you for reading! Have you ever thought about the impacts that your lights have on light pollution? Let me know in the comments below and like this post if you want more like it!