The event occurs four times a year, during which the setting sun lines up with the city's grid layout, bathing the north and south sides of every cross street with warm, orangey-pink light. Tonight's Manhattanhenge will be the second of the year; New Yorkers were previously treated to the pretty spectacle on May 29.
Current weather forecasts for New York City show a 60 percent chance of rain at sunset, which could spoil the view. But, if conditions are clear, the full effect of Manhattanhenge will be visible tonight at 8:23 p.m. EDT, when the entire orb of the sun appears on the horizon. [See Photos of Amazing Sunsets & Sunrises]
Tomorrow (July 13), the setting sun will create a similar effect for the half sunset, when half of the sun appears above the horizon, and the other half below.
For the best experience, head outside about a half-hour earlier than the time of the actual sunset, said astrophysicist Neil deGrasse Tyson, director of the American Museum of Natural History's Hayden Planetarium, in a blog post on the museum's website.
"For the best effect, position yourself as far east in Manhattan as possible," wrote Tyson, who coined the term "Manhattanhenge" in 2001, and is credited with popularizing the event. "But ensure that when you look west across the avenues you can still see New Jersey."
Some of the clearest cross streets include 14th, 23rd, 34th, 42nd, 57th and several of the streets immediately adjacent to these wide boulevards. "The Empire State building and the Chrysler building render 34th street and 42nd streets especially striking vistas," Tyson said.
But a note of caution: DO NOT look directly at the sun through a telescope or binoculars. The rays can damage your eyes, potentially causing blindness.
Manhattanhenge is a play on the name Stonehenge, a prehistoric monument that lies north of the modern-day city of Salisbury, England. Once a year, the sunrise is perfectly aligned with the stones that make up the mysterious megalith.
Several other cities in the United States with grid-patterned streets also experience similar sunsets, including Baltimore and Chicago.
Editor's note: If you snap an amazing photo of Manhattanhenge and you'd like to share it for a possible story or image gallery on LiveScience.com, please send images and comments, including equipment used, to Denise Chow at email@example.com.