Manhattanhenge

 

A Special Installment of “A Helluva Town” 

[A ”beloved event, known as Manhattanhenge, occurs when the setting sun aligns perfectly with the numbered streets that run east and west on Manhattan’s city grid, bathing traffic and skyscrapers in its warm red light.”  That’s the way Nicholas St. Fleur, a science reporter for the New York Times and a children’s STEM author, characterized this celestial spectacle in a 2016 Times article.

[For four days every year, New Yorkers and visitors to the Big Apple get excited about a daily occurrence: sunset.  In a special revival of an ad hoc series I ran on Rick On Theater for a couple of years, “A Helluva Town”—about New York peculiarities, oddities, curiosities, and idiosyncrasies—I’m going to present some of the interesting facts and factoids about this astronomical phenomenon.

[Readers who live in or near New York City and have never seen Manhattanhenge and ROTters who live somewhere else and have never heard of it should find this interesting.  Maybe it’ll entice you to come see it.  Anyone who has seen the spectacle might learn something she or he didn’t know about it. 

[In any case, it’s an intriguing marvel that happens to be real, contrived by nature, and has somehow blessed New York City above all other cities in the world.  Read on and see what you think.]

In the spring and summer of every year, New York residents and visitors are treated to some astronomical eye candy.  On two days in May and two in July, the setting Sun lines up with the city’s street grid, producing a solar exhibition perfectly staged within the proscenium formed by Manhattan’s west side skyscrapers.  The phenomenon known as “Manhattanhenge” illuminates the streetscape in evening’s warm rosiness as ol’ Sol meets the New Jersey horizon across the Hudson River.

In her 2022 New York Times article about the phenomenon (reposted on line on 30 May 2023, with updated dates and times; How and Where to Watch Manhattanhenge Tonight - The New York Times (nytimes.com)), Shannon Stirone wrote: “As if New York couldn’t become any more magical, the sunsets of Manhattanhenge illuminate the streets with a glow of deep tangerine and bubble gum pink, transforming the bustling streets into a place to pause and say, ‘wow.’”

In 2023, the spring celestial performances were on Monday, 29 May, at 8:13 p.m. New York time and Tuesday, 30 May, at 8:12 p.m.  The next showings will be on Wednesday, 12 July, at 8:20 p.m. and Thursday, 13 July, at 8:21 p.m.  On the first and fourth evening of the phenomenon, half Sol’s disk sits on the horizon (“half sun”); that is, the horizon bisects the Solar disk), but at the second and third sunsets, viewers find the entire ball of the Sun on the horizon (“full sun”).

Though Dr. Jackie Faherty, senior scientist and astrophysicist at New York City’s American Museum of Natural History, asserts that the full sun is the real star of the show, Neil deGrasse Tyson, director of the Hayden Planetarium at AMNH’s Rose Center for Earth and Space, calls the half-sun display, “My personal preference for photographs.”

Ya pays yer money and ya takes yer choice!

(Actually, it's a completely free show, of course: a natural phenomenon that happens four times a year.)

The dates of Manhattanhenge depend on when the summer solstice happens, but it doesn’t take place on the solstice itself, which was 21 June this year.  It happens about three weeks before the solstice and again about three weeks after it.  

The reason Manhattanhenge doesn’t occur on the solstice is that the city’s grid isn’t aligned perfectly with Earth’s geographic north-south axis; it’s tilted a little under 30 degrees east of the line.  There are sites on the Internet that give the astronomical reasons for this discrepancy for those who are curious—or scientifically inclined.

(Two are on the sites of Scientific American magazine and AMNH: “Manhattanhenge: What It Is, and How to See It” by Joe Rao, Manhattanhenge: What It Is, and How to See It - Scientific American, 29 May 2018, and Tyson’s “Manhattanhenge,” Manhattanhenge 2023: Where & How to See It | AMNH.)

The summer solstice, the first day of summer, occurs when one of Earth’s poles is pointed most directly at the Sun.  It happens once in each hemisphere, the northern in June and southern in December.  In each hemisphere, it’s the day with the longest period of daylight and shortest night of the year, when Sol’s at its highest altitude above the horizon at noon.

(There’s also an opposite phenomenon known as “Reverse Manhattanhenge” or “Winter Manhattanhenge” which occurs on the east side of the island during sunrises over the East River and Long Island in early January—the 11th and 12th last winter—and late November—the 29th and 30th this fall.  

(Reverse Manhattanhenge is associated with the winter solstice—the first day of winter—in the same way as Manhattanhenge is with the summer one.  The January event followed the winter solstice of 21 December 2022 and the November display will precede the solstice on 22 December 2023. 

(Reverse Manhattanhenge is a less popular spectator draw than the sunset event because of its early hour—a little after 7 a.m.—and the chilly temperatures at dawn in the late fall and winter, usually between 30 and 60 degrees Fahrenheit, or -1 to 16 degrees Celsius.

(Aside from the cold—and even possible snow for the January event—less conducive to good viewing for the morning phenomenon is that the cityscapes of Long Island across the East River are closer to Manhattan than the expanses of New Jersey across the wider Hudson.  The eastward views can be obstructed by the tall buildings of Brooklyn and Long Island City, Queens.  Bad visibility due to cloudiness is also more common in winter and late fall than in summer and late spring.)

Obviously, the solar alignment existed before modern-day Manhattanites began celebrating it in the late 20th century—at least 18,000 years ago when the last ice age carved out the island and the landscape beneath New York City—but Sol-worshipers are the beneficiaries of the island’s rectangular grid plan that was conceived in 1811 and was implemented over the succeeding 60 years. 

The name “Manhattanhenge,” according to most sources, was coined and then popularized by astrophysicist Neil deGrasse Tyson (b. 1958), arguably the best-known astronomer in the United States since Carl Sagan (1934-96).  Tyson devised the term as a deliberate invocation of England’s Stonehenge after he visited the 5,000-year-old site on Salisbury Plain as a boy of 15.  That trip was led by Gerald Hawkins (British; 1928-2003), an astronomer who first proposed that Stonehenge's purpose was to predict the movements of the Sun and stars in his 1965 book Stonehenge Decoded. 

Though the actual purpose of Stonehenge is a mystery, despite many theories, when the Sun rises on the morning of the summer solstice, it aligns perfectly with several of the stones of the Druidic monument, signaling the change of season.  Tyson, born in Manhattan and raised in the Bronx, recognized the similarity with the New York phenomenon—though, of course, Stonehenge is presumed to have been intentionally designed to effect the astronomical event, while Manhattanhenge is happenstance.

Tyson’s interest in astronomy began, he’s said, as a child of 9 when he visited the very institution which he now directs, Hayden Planetarium.  The lore is that he invented the name in 1977 (when he’d have been about 19), but in his long and multi-faceted career in science, Tyson wrote the “Universe” column for Natural History magazine (at the time, published by AMNH, the parent institution of the planetarium, where he’d just been appointed director) and in 1996, he described the New York City phenomenon of Manhattanhenge, spreading the name among the column’s readers.

“Cityhenges” happen in other cities around the globe beyond New York.  There are also Chicagohenge, Bostonhenge, Phillyhenge, Baltimorehenge, Torontohenge, Montrealhenge, and even Madridhenge and Strasbourghenge, among others.  If the city’s streets are oriented close to east-west, there’s likely to be a “henge.”  Would-be sunset-watchers only need to find out when the phenomenon happens in their city. 

(There are dozens of sites on the ’Net that carry the times and dates of Manhattanhenge each year as well as the best places to watch the show; “Manhattanhenge,” on the website of the American Museum of Natural History [link noted above], is updated each year, for instance.)

As Tyson points out, by the way, an examination of the situations in other cities around the world reveals that despite the east-west grid, most lack an unobstructed view toward the horizon.  Manhattan, though, has a clear line to New Jersey, afforded by the vista across the Hudson River.  Furthermore, Gotham’s phalanxes of tall buildings lining its streets create a vertical frame for the setting Sun that reflects its crepuscular glow.

Tyson observed that thus, “Manhattanhenge may just be a unique urban phenomenon in the world, if not the universe.”

(Reverse Manhattanhenge has the same advantage for the semiannual sunrise sighting, but that’s countered by the weather and time of the event.  In addition, as Tyson has also said, Manhattan is “a place where evening matters more than morning.”)

Choosing the best location from which to see Manhattanhenge is largely a matter of personal preference.  Some of that’s affected by where one lives or, for visitors to the Big Apple, is staying.  Do you insist on just stepping out of your building and catch the sight, or will you travel—and how far?

Most henge-watchers suggest that the main crosstown streets—57th, 34th, 23rd, and 14th Streets—are best, depending mostly on one’s aesthetic desires for the framing structures.  42nd Street is a popular viewing site not despite the flashing signs, but because of them.

There are other vantage points, including off Manhattan Island, and the various websites as well as the newspaper coverage of the event, include information about them.  Just keep in mind that Manhattanhenge is a popular spectator event, even among Gothamites (yes, even the jaded and blasé New Yorkers get excited over this celestial spectacle).  Popular viewing sites such as 34th Street near the Empire State Building (at 5th Avenue) and 42nd Street near the Chrysler Building (Lexington Avenue) get very crowded.

Manhattanhenge advisers recommend finding a spot along the east-west cross streets as far east as possible (that is, back towards the East River, away from the Hudson) that still affords a view of New Jersey across the Hudson River.

The smaller, quieter cross streets might be more inviting, but spectators and photographers will lose the perspective of the wide vista and the skyscraper frame as the setting Sun is reflected off our urban canyon walls.  They’d also have to get closer to the river in order not to have the sight of the Sun itself obscured as the street opening in the west narrows from the perspective.

On the other hand, being able to stand in the middle of the street, the only way really to see Manhattanhenge fully, is probably easier and safer on a small street than one of the two-way thoroughfares.  Remember, traffic isn’t halted for Manhattanhenge and New York City has a 24-hour rush hour!  Do not expect a New York cabbie or a Manhattan driver to wait while you line up the perfect snapshot of the other Ball Drop.

ROTters may infer from some of my foregoing remarks that photography is a major component of the Manhattanhenge experience.  Particularly with the advent of cell phone cameras, the semiannual event’s become a shutterbug’s dream.  Most of the websites on Manhattanhenge feature lots of photos, most of them taken by ordinary spectators. 

The pros do it, too, of course, but they’ve largely been there, done that years ago, and though the event is always spectacular—not counting the times when bad weather, such as rain, fog, or clouds (or haze such as what we experienced here a few weeks ago because of Canadian forest fires) interferes—one of the characteristics of Manhattanhenge is that it never really changes year to year.

As for the timing, if you follow the published schedule from a newspaper or website, just gauge your arrival for enough time to beat whatever crowds are likely to gather.  The main cross streets, especially in midtown, will attract larger gatherings than the smaller ones.   A good piece of advice is to scope out the viewing site you think you want to use beforehand to be sure it’s the best place to see the horizon in New Jersey, without hills, trees, or structures blocking the sightline.

Allow time to stake out a good vantage spot for viewing, picture-taking, or hopping in and out of the roadway.  Most henge-watchers enjoy seeing the Sun as it descends onto the horizon line, so plan to arrive and take a viewing position between 20 and 30 minutes—some advisers even suggest a full hour—before the time listed, as that’s when the Solar disk has reached its nadir and is sitting on the horizon.

If you’re calculating the start of the phenomenon on your own based on when sunset is scheduled—weather reports on TV and in the paper usually include the times of sunrise and sunset—consider that Manhattanhenge, despite being labeled a “sunset” event, isn’t actually at sunset, which is the time the Sun disappears below the horizon, which is when Manhattanhenge is over. 

Be prepared to arrive at least a half hour before the time designated as “sunset”—earlier, if you want to watch the event unfold.  Beware, however you reckon the event timing, that once the Sun’s disk kisses the horizon, it will remain visible for only a minute or two before disappearing entirely below the horizon line.

(The schedules specifically published for Manhattanhenge have already done this calculation.  The websites I referenced above are probably accurate, and so are the major TV news shows and papers like the New York Times and other major dailies, but with other sources, it wouldn’t hurt to check on a computer or cell phone when sunset is and doing the math.)

Just as there are other cities around North American and on other continents where one can experience a henge event, one can see an approximation of Manhattanhenge at other times right here in the Big Apple.  If you aren’t picky about how close the Solar disk gets to the horizon in the New York City canyons, the Sun will be visible somewhere between the skyscrapers when it’s close to setting every evening between late May and mid-July.

Sol will appear to pass between the Manhattan uprights higher and higher above the horizon each night as the summer solstice approaches from the first Manhattanhenge date to the solstice, and then lower and lower between the solstice and the last henge date.  This is known as the “Manhattanhenge Effect,” and it doesn’t attract the crowds that the true Manhattanhenge does.

[Neil deGrasse Tyson was born in Manhattan on 5 October 1958 to Sunchita Feliciano Tyson (b. 1928), a gerontologist for the U.S. Department of Health, Education and Welfare (precursor of the Department of Health & Human Services), and Cyril deGrasse Tyson (1927-2016), a sociologist, human resource commissioner for Mayor John Lindsay of New York City (in office: 1966-73), and the first Director of Harlem Youth Opportunities Unlimited.  

[Tyson’s passion for astronomy began during his high school years at the Bronx High School of Science (Class of 1976), eventually leading to his giving lectures in the field.  He declined an invitation from Dr. Carl Sagan to participate in undergraduate programs at Cornell University and instead pursued a major in physics at Harvard College, where he received his Bachelor of Arts degree in 1980.

[Tyson continued his education, earning a Master of Arts in astronomy from the University of Texas at Austin in 1983 and a Master of Philosophy in astrophysics from Columbia University in 1989.  He went on to complete his doctorate in astrophysics at UT–Austin and embarked on a career that included positions at Princeton University, the Hayden Planetarium, the American Museum of Natural History, and the University of Maryland.

[In addition to his research and academic endeavors, Tyson has written books, articles, and a column for Natural History magazine called “Universe.”  Tyson has also played active roles in aerospace commissions and received honors, including NASA’s 2004 Distinguished Public Service Medal.  Throughout his career, Tyson has been an advocate for NASA and continues to support its growth and operations.

[Tyson’s involvement in popular science TV programs, such as 2007’s The Universe on The History Channel, has made him a familiar face in science communication.  In 2014, he helped revive Carl Sagan’s 1980 television series, Cosmos: A Personal Voyage, presenting Cosmos: A Spacetime Odyssey on both Fox Broadcasting and the National Geographic Channel.  In 2020, Tyson returned with a follow-up season entitled Cosmos: Possible Worlds.

[Tyson’s expressed his personal views on spirituality, religion, and science in essays like “The Perimeter of Ignorance” (Natural History, November 2005) and “Holy Wars” (Natural History, October 1999).  He’s appeared in several movies and on numerous television shows such as Nova on PBS and CBS’s The Big Bang Theory, and many talk shows, both daytime and late-night, including 16 appearances on The Late Show with Stephen Colbert (and another 11 on The Colbert Report).]