Joe Guzmán remembers the first time he saw Saturn. He was 12 years old, peering through a telescope in the backyard of his Pilsen home when a bright spot caught his attention. “I finalized the focus … BANG!” he says. “It was Saturn. Ball, ring around the planet. I could see the Cassini Division in the rings. Oh my god, I still get chills thinking about it now. This was not in a magazine, a book, a TV — it was a one-on-one relationship with this planet.”

Guzmán has since spent decades nurturing this relationship by studying the skies. A telescope operator for the Adler Planetarium, he also serves as the resident astronomer for the Chicago Park District and the 606 trail. But he’s long encouraged Chicagoans to develop their own connections to the cosmos. Since 2004, Guzmán has hosted public observation sessions around the city, gradually building a community of astronomy enthusiasts through his online forum Chicago Astronomer. He’s known to some as Astronomer Joe.

On a Monday evening, Astronomer Joe hauled his gear to a typically astronomer-free setting: the rooftop at Londonhouse. He set up the 11-inch Schmidt-Cassegrain telescope near the glass barriers so it overlooked the Chicago River, facing Marina City, the Langham, Trump Tower. It wasn’t quite dark enough to aim it skywards, so he encouraged curious onlookers around him to observe the skyscrapers around them.

“You wanna look?” he called out to revelers, many coming straight from the office. “It’s free!” Gradually, people sidled up to him, drink in hand. (Bartenders whipped up a special cocktail for the evening: "The Copernicus," a concoction of gin and St. Germain, complete with a glow-in-the-dark ice cube and sugared rim to evoke the starry night.) Astronomer Joe pointed out the Wrigley Building, the top of the Tribune tower, the laptop-shaped roof of the Apple store. At one point the telescope swiveled towards Trump Tower. “Is he looking into a hotel room?” a man asked his drinking buddy, incredulous at the thought. “That’s kind of messed up.” Others giggled. “Anybody doing anything good over there?” someone cried out.

“I’ve never seen anything scandalous,” Astronomer Joe said, shrugging. A woman, introducing herself as Desiree, interrupted. “Just wondering what you guys are looking at,” she said. “When are we going to see the stars?” Astronomer Joe told her she had to wait a little longer. In the meantime, he shared some tips for urban stargazing: Find a local astronomy club. Get a pair of binoculars (“They will open up the vista to the skies”). As for the best place to see stars in the city? Northerly Island, where there’s minimal light pollution.

Before he was a Parks District astronomer, Guzmán worked as an investigative reporter for corruption and incompetence in the Chicago public school system. He also spent 20 years as a civilian instructor in the Chicago police department. “I answered the skies call,” he said. “I’ve been doing it for decades and never tire of it.”

“So you’re a public astronomer,” Desiree offered.

“Yes I am! That’s a beautiful title.”

Things got more exciting as the night marched on. We saw Vega, bright and shiny, Jupiter, and Io. “I love Io,” said Barbara, a member of Guzmán’s crew who has purple streaks in her hair. “Io spits at Jupiter, it has volcanoes coming out.” She nudged more giddy adults towards the telescope. Then, the arrival of Guzmán's lifelong friend: Saturn, the highly anticipated sphere of the evening. It shone bright through the lens, upside-down and tiny; its rings were shockingly clear. A young man in a beret, dazzled by the sight, attempted to photograph it through the telescope's lens with his iPhone.

In a nearby corner, two young women took boomerangs of their cocktails, and their companion wanted to know: Has Astronomer Joe ever seen anything strange? “I have seen two strange things,” he recalled. “I was looking at a half moon out by the Adler. I see this oval-shaped object pass in front of it in a controlled manner. It wasn’t an airplane. There wasn’t a chemtrail behind it.

“And then I see another one — same latitude, same shape, same speed — and I anticipate a third. I wait, and here comes another one — same latitude, same shape, same speed. And then comes another one. I follow it, and it’s going slow. And then I lose it. What could it be? It looked like it was beyond the atmosphere. If it were UFOs, they would have to be huge spacecrafts, city-sized, for me to catch this. I had absolutely no idea what this was.”

A woman tapped his shoulder before he could share his second strange sighting. “I don’t see anything in there — just darkness,” she said, her cheeks rosy. “I think we need more power!”

Her date stood patiently behind her. “Are you an astronomy person?” he asked.

“Me? I only like wine,” she replied, turning back to peer at Saturn.

She waved Astronomer Joe over. He guided her to clarity, moving her hand away from the telescope. He fine-tuned the focus so the Cassini Division was clear.

“I see it now,” the woman cried, stumbling away from the setup. “It’s beautiful.”