'Manhattanhenge' to light up New York on Tuesday

What, exactly, is Manhattan? And who were the primitive people who built it?

We may never know. All we know is that twice a year, mysteriously, the setting sun aligns perfectly with the city's east-west street grid. "Manhattanhenge," they call it — as in "Stonehenge," another primitive monument where a similar phenomenon occurs.

On Tuesday, Manhattanhenge is back — at 8:13 p.m., barring rain. 

"I think, as a visual event, it can be very rewarding," says Gary Swangin, manager of Paterson's Panther Academy Planetarium. 

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Many tourists would agree.

Ever since bthe superstar astrophysicist Neil deGrasse Tyson drew attention to the striking phenomenon — and coined the term "Manhattanhenge" for it — anyone within hailing distance of an Uber and an iPhone has hurried out to the city's prime cross streets (14th, 34th, 42nd, 57th, and 79th are recommended) on designated afternoons, to photograph the sun shining directly down the canyon walls of the city like a flashlight in a narrow closet.

If you miss Manhattanhenge on Tuesday, you'll have three more opportunities this summer.

Manhattanhenge will be back the following day, Wednesday, at 8:12 p.m., and then two months later on Thursday, July 12, at 8:20 p.m. and Friday, July 13, at 8:21 p.m. The May 29 and July 13 dates, it should be noted, are "half sun" events — only half the orb will be sticking up over the horizon. May 30 and July 12 are "full sun" events.

Manhattanhenge has also been dubbed the "Manhattan solstice." That's a misnomer, since the actual summer solstice — the longest day of the year, when the sun is highest in the sky — is June 21.

That's the day when the sunrise aligns perfectly with the actual Stonehenge.

England's famed circle of prehistoric monoliths (c. 3000 B.C.) is a timeless mystery that has proven irresistible to historians, hippies, neo-Pagans, and the band Spinal Tap. A religious site? An ancient observatory? An alien artifact?

Your guess is as good as Erich von Däniken's — or possibly better.

"We don't know exactly who built it," Swangin says. "People say the druids did, but no one knows for certain. The stones are aligned to mark the beginning of summer, as well as the beginning of winter.  We don't know if it was constructed as an astronomical observatory, or a religious monument to note the position of the sun at different times of year."

In Manhattan, the alignment of the street grid and the sun's trajectory is not so perfect, alas.

The city's street plan, as Tyson has pointed out, is not aligned with the geographic North — it skews 30 degrees east. That's why  "Manhattanhenge" misses the solstice by several weeks.

Nevertheless, when people observe Manhattanhenge, they're echoing an ancient impulse, Swangin says.

"What they're doing, essentially, is related to what people have done for thousands of years, looking at the sun aligned with certain structures," he says.

Manhattanhenge

WHEN TO SEE IT:

8:13 p.m. May 29.

8:12 p.m. May 30

8:20 p.m. July 12

8:21 p.m. July 13

WHERE TO SEE IT:

14th Street, 34th Street, 42nd Street, 57th Street and 79th Street are recommended.