Nine people are crammed in a tiny room with no ceiling on the grounds of Kitt Peak National Observatory. It’s cold. It’s dark. Each person awaits a turn at the eyepiece of a 20-inch telescope trained on an object. A marbled sphere, swirled in colors of maroon, rust, and cream. It’s Jupiter, a fellow planet in our solar system, fifth from the sun. “Look at that black speck that kinda looks like dirt on the lens,” says guide James Schweder. “That’s Io, one of Jupiter’s moons, casting its shadow on the planet.” He puts the show in perspective. “You’re basically watching a solar eclipse from more than 417 million miles away.”

The ultimate star city

With a surfeit of blockbuster attractions as the Grand Canyon, Sedona, Monument Valley and the Hoover Dam in the state, travelers to Arizona can be forgiven for overlooking the fact that its second largest city, Tucson, is a world capital of astronomy. The surrounding mountains host the world’s largest concentration of astronomical scopes and spectrographs.

The U.S. national observatory is here, and so is the Vatican’s (dubbed the “pope scope”). The world’s largest public telescope sits atop Mt. Lemmon. The only facility to manufacture the world’s largest mirrors for telescopes is located under the east side bleachers of the University of Arizona’s football stadium (no, really).

There are six Dark Sky parks and communities in the area, including a desert park recently named the world's ninth Urban Night Sky Place. And Tucson itself is the headquarters of the movement to protect the world’s dark skies and a model city committed to dark sky preservation. The city’s new Astro Trail—officially unveiled in January—strings together 11 of the most visitor-friendly stops in a downloadable map.

“It’s the weather—clear and dry—plus easily accessible mountains to put telescopes on,” notes Thomas A. Fleming, astronomy professor at the University of Arizona. “This attracted a cast of characters, especially during the early formation of NASA, and converged to make Tucson a hot place to do astronomy.”

In 1967, a high-resolution photographic atlas of the moon used to plan the lunar landing was partly developed at the University of Arizona's Lunar and Planetary Laboratory using images from the 61-inch telescope on Mount Bigelow in Arizona's Catalina Mountains near Tucson. Today, Tucson-area observatories and research institutions conduct groundbreaking studies on dark energy, exoplanets, and gamma rays, while also creating a detailed 3D map of the universe and capturing the first-ever image of a black hole.

(Related:Dark sky tourism is on the rise across the U.S.)

Protecting natural darkness

As the industry grew, and Tucson’s population with it, preventing light pollution became a business necessity. The city’s first outdoor lighting ordinances were adopted in 1972. The current code requires shielded lighting and sets limits on the total light produced at night, especially in natural areas and near astronomy sites. In 2019, the city retrofitted nearly 20,000 street lights to adaptive LEDs, saving $2 million of dollars in annual energy costs and resulting in a seven percent reduction in total light emissions from the metro area.

“The prescription for light pollution isn’t plunging the world into medieval darkness, or compromising safety,” says Ruskin Hartley, CEO of the nonprofit DarkSky International, which is based in Tucson. “It's about being wise about the way that we're using it, using it strategically and responsibly.”

What's happened over the almost 40 years is a recognition that protecting natural darkness is not only good for astronomy, but also for wildlife and human health. “There's nothing like being out in the desert or even in downtown Tucson on a moonless night and seeing the Milky Way overhead. That is taken away from us if we blast our lights. So that what started to protect astronomy is actually part of protecting the way of life down here in southern Arizona.”

(Related:10 of the dreamiest stargazing trains in the U.S.)

Astrotourism on the rise in Tucson

Interest in celestial events and night-sky viewing is at an all-time high. A recent Booking.com survey showed 62 percent of respondents said they were considering visiting destinations for stargazing. Last year’s solar eclipse over North America was one of the most viewed in history, with nearly 20 million people traveling to the path of totality in the United States alone. And dark sky-designated locations have multiplied to more than 200 around the world, with the number of places seeking certification doubling in the past two years.

At Mt. Lemmon SkyCenter, visitors can peer through the largest dedicated public telescope in the U.S., with a refractor almost three feet across, designed to see solar system planets as well as deep sky objects, such as nebulae. Kitt Peak offers perhaps the closest experience you can have to being an actual astronomer, an overnight program that lets you dine at the same cafeteria as working astronomers, then peer at deep-sky objects from cutting-edge research telescopes for as long as you can stay awake.

Not technically astronomy-related, but nevertheless Space Age–y, the Titan Missile Museum displays the only remaining Cold War–era Titan II intercontinental ballistic missile site open to the public. Visitors can also tour Biosphere 2, a failed experiment in the early 1990s in sustaining life in space, now focused on simulating various eco-zones and conducting experiments in astrobiology to answer the question of whether life can exist outside the Earth.

(Related:These are the world’s best stargazing spots.)

Just as professional astronomers come for work, hobbyists come to play, often choosing Tucson as a place to retire. “Driving around town, it’s not unusual to see a home that has an observatory dome connected to the house,” says Fleming. Founded in 1954, the Tucson Amateur Astronomy Association has more than 850 members. Volunteers often run the telescopes and point out constellations for school programs and events, including the free Tucson Astronomy Festival, held annually in the spring.

At the SkyBar on Fourth Avenue, diners enjoy pizza made in a solar oven, down “cosmic jello” shots, and peer through one of four telescopes on the patio, guided by a “star-tender,” one of whom is named Kirk. Full-moon hikes and star parties are held at area parks, including Saguaro National Park, Oracle State Park, and Catalina State Park. Several hotels and inns cater to astrotourists, including Loews Ventana Canyon, which hosts complimentary stargazing three nights a week with a local astronomer. Guests staying at the Cat Mountain Lodge receive a discounted rate on star tours at the privately owned observatory next door.

(Related:10 of the best places for stargazing in the UK.)

View of the Milky Way from a sacred mountain

The highest peak in the Quinlan range, Kitt Peak, at nearly 7,000 feet, is a sacred mountain located within the territory of the Tohono O’odham Nation, a Native American tribe that traces its heritage to the ancient Hohokam people. Not far is another sacred peak where the creator I'itoi, is said to reside. The U.S. national observatory was placed here in 1960 with tribal permission. It’s a good spot to ponder the big questions.

According to Jacelle Ramon-Sauberan, tribal member and education development liaison at Kitt Peak, the night sky is a gift from I'itoi, impossible to separate from the people without tipping the balance. “The animals, the plants, the cactus, the mountains, the clouds, the stars—all those are in that same category as humans; they have a living spirit, and we acknowledge them just like we would our parents or our grandparents. They’re family, essentially and it is part of our himdag, or way of life, to preserve the balance.”

For the majority of its existence, half of humanity’s lived experience was after dark. The night sky helped humans mark time, predict weather, signal seasons, and make sense of humanity’s place in the cosmos. Yet today, according to DarkSky International, 95 percent of the world’s population live under light-polluted skyglow, with many never having seen the Milky Way.

(Related: A practical guide to stargazing.)

To Vicky Derksen, host of the podcast Night Sky Tourist, we’ve disconnected from a large part of what makes us human. “But if people get an opportunity to look at Saturn and they say, ‘oh my god, I can see the rings’ or they actually see one of Jupiter’s moons or glimpse a shooting star from the corner of their eye. Then they walk away feeling like they've had this deep intimate connection with the sky that they didn't know existed.” Scientists who study this feeling of awe and wonder connect it to well-being and happiness.

Standing under a gauzy Milky Way, Kathie Zelaya, another of the night guides at Kitt Peak, reminds participants that while it’s nice to have the big cameras and the fancy telescopes, you don’t necessarily need much equipment. “On a clear, dark night, there's a lot you can see with binoculars, or even just with the naked eye.” Zelaya demonstrates how to change the settings of a smartphone to capture the natural light show. “Remember, wherever you are, this is always up there,” she says with a grand sweep of her arm. “But here you can see it just a little better.”

(Related:What’s a ‘dark sky nation’ and why does New Zealand want to become one?)

What you should know about Tucson’s Astro Trail

A global astronomy hub, Arizona’s second city boasts more than two dozen professional scopes and observatories that look to the skies. The Tucson Astro Trail connects 11 stops within about an hour’s drive. It is available as a web app and printed guide, offering visitors a comprehensive journey through the city's space-related sites and activities. There’s no cost apart from any admission fee individual sites may charge. Additionally, visitors can sign up for a digital passport to earn points and win prizes.

(Related:Big Sky, brighter stars: Why Montana is 2025's ultimate stargazing destination.)