"Look! There's Deneb!" Dulsky pointed to the left of Vega. And there was Altair, lower and right, completing the Summer Triangle.
Next came Saturn, then the earliest lights in the constellation Scorpius. Minute by minute, the sky was thicker and thicker with stars.
By 10:30, when full darkness had settled in, the Milky Way - with its billions of stars - was a smoky belt running north to south across the entire sky.
Dulsky, of Perkasie, struggled to put into words what he was seeing. Finally, he decided he could not.
"It's unlike anything you'll see in the Philadelphia suburbs," he said. "It's awesome."
Many 21st-century Americans have never seen what you can see here, 2,300 feet above sea level, in one of the most thickly wooded regions of the Mid-Atlantic.
The nearest town, the tiny Potter County seat of Coudersport, is 500 feet lower and 15 miles away.
At sunset, more deer and turkeys than cars roam the narrow two lanes of Route 44. What little light might intrude from the road is blocked by tall stands of firs.
The International Dark-Sky Association, which lobbies in Washington to curb light pollution, has certified Cherry Springs as one of a handful of "international dark sky parks" in the nation.
What that means, director Bob Parks said, is not only that the park is very, very dark, but also that local organizations are working to keep it that way by turning down lights where possible and capping lights that remain on.
Parks said of Cherry Springs: "It is one of the darkest places east of the Mississippi."
Some dark-sky enthusiasts would hold out for a corner of West Virginia as just as dark or darker. And parts of Acadia National Park in Maine could make a case for bragging rights.
