On an island some 50 miles north of the city, Melissa McGill is hard at work, recreating the ruined Bannerman Castle through Constellation, a stunning light-based public art project that combines sculpture, astronomy, architecture, and history.

As the sun sets each night for the next two years, a series of 17 hand-blown glass globes will light up for two hours, acting as shining beacons hovering above the river.

Each globe and LED light is strategically placed on thin aluminum poles, which range in height from 40 to 80 feet tall. Some tower above the ruins, marking the castle’s former height, while others correspond to current architectural features, creating a twinkling constellation that connects the island’s past as a refuge for bootleggers and misfits to its uncertain future.

Constellation is also heavily inspired by the indigenous Lenape people, the original inhabitants of the area, whose spiritual beliefs included a “white road” in the heavens, that connected them to the spirit world through the Milky Way, which they called the Opi Tamakan.

“Like so many who travel and live along the Hudson River, I’ve had a long fascination with the mysterious castle ruin and this island,” explained McGill in a press release. “As I investigated its history and reimagined its present, I was moved to create a project that continues my work exploring the space between absence and presence, bringing to light the overlooked, hidden, or lost aspects of architecture, found objects, and places.”

Now known as Pollelpel island, the tiny isle is an accident of New York’s glacial past; it once hosted Revolutionary soldiers, who unsuccessfully built a row of underwater spikes to keep the British from sailing upriver.

The castle itself is a relic of the 20th century, and was built by Francis Bannerman VI as a military surplus warehouse. The building was partially destroyed in 1920, when 200 tons of shells and gun powder exploded.

It took McGill, who is represented by CRG Gallery, three years to bring the project to life, personally organizing ever detail and working to raise money, enduring countless grant proposal rejections. The National Endowment the the Arts eventually came on board, but the $20,000 grant covered only a fraction of the $650,000 budget.

“It’s so rare for someone to pull this kind of thing off as a single independent artist, in an area that hasn’t had a lot of these kind of projects,” Anne Pasternak, president and artistic director of Creative Time, told the New York Times. When McGill first sought her advice about making Constellation a reality, “I said to her I didn’t think she’d ever get it to happen.”

Against the odds, Constellation opens this weekend. Visitors will be able to view the project while traveling on the Metro-North railroad, driving alongside the river, or hiking along nearby trails.

There are also official boat tours from the Bannerman Castle Trust and the New York State Parks Department, and kayak trips from Storm King Adventure Tours.