'Manhattanhenge' effect has sun aligned perfectly with street grid, creating 'radiant glow'

PHOTO: The sun appears along 42nd Street during a sunrise Manhattanhenge in New York City, Jan. 14, 2018, as seen from Weehawken, N.J.PlayGary Hershorn/Getty Images
WATCH What is Manhattanhenge?

Manhattan will experience a special event tonight, known as Manhattanhenge, when the sun aligns perfectly with the street grid, illuminating both the north and south sides of every cross street in the borough. This occasion occurs just twice a year.

The name for the event was coined by famed astrophysicist Neil deGrasse Tyson who is the director of the Hayden Planetarium at the American Museum of Natural History.

The phenomenon creates "a radiant glow of light across Manhattan's brick and steel canyons ... A rare and beautiful sight," Tyson wrote on the planetarium's website.

Manhattan's north-south street grid is not perfectly aligned with the geographic north-south line. If it had been, the event would happen at the same times as the spring and autumn equinoxes.

PHOTO: A woman rides a bike on 42nd Street in New York City during Manhattanhenge, July 12 2016. Kena Betancur/AFP/Getty Images
A woman rides a bike on 42nd Street in New York City during Manhattanhenge, July 12 2016.

On the two days of Manhattanhenge, spectators can see half of the sun below the horizon and half above. Two days around these times also offer what Tyson calls "Manhattanhenge moments," when the full sun is visible on the horizon.

Half of the sun will be visible tonight around 8:13 p.m. and on July 13 around 8:21 p.m.

The full sun will be visible tomorrow around 8:12 p.m. and July 12 around 8:20 p.m.

PHOTO: In this file photo, the sun rises above 42nd Street in New York City, Nov. 28, 2016, as seen from Weehawken, N.J. Gary Hershorn/Getty Images
In this file photo, the sun rises above 42nd Street in New York City, Nov. 28, 2016, as seen from Weehawken, N.J.

According to Tyson, to see the best effect, spectators should position themselves as far east in Manhattan as possible. Tyson also recommends that people stand on avenues where they can clearly see New Jersey. Streets like 14th, 23rd and 34th.

Tyson says that while other cities can identify days where the sun aligns with their streets, the conditions are not as ideal as the grid in New York City.

It’s possible that Manhattanhenge is a unique urban phenomenon not just in the world, but in the universe, according to Tyson.