Stephens' interest in the night sky dates back to the 1970s, when he was in college pursuing an accounting degree. After following the lead of a friend and joining the Riverside Astronomical Society in Southern California, he experimented with astrophotography and observing variable stars. He put his hobby on hold during the 1980s to start a family and his accounting practice.

His enthusiasm for astronomy re-ignited in the 1990s with the proliferation of charge-coupled devices, or CCDs, digital camera sensors that can collect photons during long telescopic exposures of the night sky. With the help of CCDs, amateurs could record objects too faint to see with their own eyes through their telescopes—without the hassle of developing film. Stephens got back into his old hobby, and a friend took him on a tour of Palomar Observatory northeast of San Diego. There, he met Carolyn Shoemaker and David Levy, two of the three astronomers who found comet Shoemaker-Levy 9, which slammed into Jupiter in 1994. Shoemaker and Levy were preparing for an observing run, and Shoemaker asked Stephens if he wanted to see the photographic plates used to discover Shoemaker-Levy 9.

"I said, 'Well, yeah—they aren't in the Smithsonian?' And she said, 'Oh, no, I've got them right here.' And she pulls them out of her purse," Stephens said.

He joined Shoemaker and Levy for dinner at one of the small houses reserved for astronomers on the mountain, and when the group returned to the telescope, they found Stephens' car had been locked inside the observatory gates.

"I guess you're spending the night, huh?" he recalled Shoemaker saying. That he did, helping the two astronomers observe asteroids.