Telescope Farm

 

[A "telescope farm” is an observatory in a remote location with dark, clear skies (“Dark Sky Places”; see below in the afterword to the second CBS News report) where amateur astronomers can house their own telescopes or rent access to existing ones.  Users control these telescopes remotely via the internet, often from the comfort of their homes, to capture high-quality astronomical images without dealing with local light pollution (see the last two articles posted below).

[Key characteristics of a telescope farm include:

•   Remote Operation: Astronomers can be located anywhere in the world and operate the equipment via an internet connection.

•   Dark Skies: The facilities are situated in locations with minimal light pollution, such as rural Texas or regional Australia, which allows for much clearer and more detailed observations than those possible in or near urban areas.

•   Automated Infrastructure: The sites feature automated systems, such as sheds whose roofs open and close in unison, to protect the equipment and facilitate remote, often scheduled, operation.

•   Accessibility: This business model makes high-quality astrophotography and research accessible to amateur stargazers and researchers who may not have the resources, location, or time to operate a personal observatory. 

[Companies like Starfront Observatories in Rockwood, Texas, in the U.S. and iTelescope in Coonabarabran, New South Wales, Australia, are examples of businesses that provide these services.] 

“LIGHT POLLUTION IS WASHING OUT THE NIGHT SKY.
A REMOTE TELESCOPE FARM HELPS STARGAZERS
BRING THE COSMOS TO THEIR SCREENS”
by David Schechter, Aparna Zalani, and Jojo Macaluso

[I was watching the evening news last Wednesday, 12 November, when I caught a report about a telescope farm in remote Central Texas.  The story fascinated me, even though I’m not an amateur astronomer.  I immediately downloaded the online report from the “Eye On America” segment of that evening’s CBS Evening News, and did a little additional ‘Net surfing, to make a potential post for future use on Rick On Theater.

[As it happens, I’m in the process of finishing another post that’s taking more time than I anticipated, so I decided to go ahead and post “Telescope Farm” now, just because I think it’s an interesting story.]

By day, a row of plain-looking sheds in sleepy Rockwood, Texas, looks like nothing more than a place to store farm tools and feed. But when the sun dips below the horizon, their roofs peel back in unison to reveal a hidden network of hundreds of telescopes. 

The so-called telescope farm is the brainchild of amateur astronomer Bray Falls, who turned his passion into a business when he co-founded the company Starfront Observatories 18 months ago.

“It has not gotten old yet. It’s so cool, every single time,” Falls said of the transforming sheds.

Starfront rents space to customers who ship their telescopes to the farm and control them via the internet from the comfort of their homes. The remote location allows amateur stargazers to take stunning pictures they wouldn’t be able to from home, because the sky in Rockwood is much darker than where they live — helping solve one of amateur astronomers’ biggest problems: light pollution. 

The night sky has gotten harder to see due to a 10% yearly increase in light pollution over the past decade, according to a 2023 study published in the journal Science [see below]. 

Starfront’s customers live all over the world, including Europe, Asia and the Middle East, Falls said.

Chuck Ayoub in suburban Detroit has a garage full of telescopes, but he hardly uses them anymore after shipping one out to Texas.

“The big difference are the dark skies. I am 20 minutes from downtown Detroit, and that light pollution is a killer,” Ayoub said.

Most nights, Ayoub livestreams his telescope feed to his large social media following. There’s also a small camera at the base so he can see his telescope in action.

From the Starfront property, Falls and others are identifying celestial objects no one has ever seen before, such as a photo he calls the “Crown of Thorns” nebula. The discoveries are furthering our understanding of space, even as our ability to see it is fading.

When asked about the threat posed by light pollution, Falls said, “It really prevents people from dreaming, like seeing what’s above them, just awe. You get the tingles, you get the goosebumps.”

But now, it’s a feeling you can get — even from your basement in Detroit.

[David Schechter is a national environmental correspondent and the host of “On the Dot with David Schechter,” a guided journey to explore how we’re changing the earth and earth is changing us.  His work has been honored with a 2021 Alfred I. duPont-Columbia University Silver Baton for reporting about climate change.  He’s also a two-time winner of the national Murrow Award for documentary, three-time Scripps Howard National Journalism Award winner, recipient of the Walter Cronkite Award for Excellence in Political Reporting and a James Beard Award Finalist.

[Aparna Zalani is an award-winning journalist for CBS News and Stations with over 25 years in journalism.  Before joining the CBS News Innovation Lab, she reported for MSNBC on major stories like the 2000 Florida election recount, the 9/11 attacks, and the 2011 Japanese tsunami.  An alumna of the NBC Page Program, Aparna joined the special projects unit at CBS Texas in 2013, working on local and state investigations, and covering medical and health stories.  She began her career in India at United Television (UTV), reporting for India Business Week.

[Jojo Macaluso is a Broadcast Associate at CBS News since January 2024; her prior experience includes positions as a News Assistant and a Production Intern at CBS News, as well as internships at NPR and dot.LA.  Macaluso has also contributed as a Quality Assurance Tester at UserTesting and a Technical Assistant at the Smithsonian American Art Museum.]

*  *  *  *
“LED LIGHTS ARE ERASING OUR VIEW OF THE STARS
— AND IT'S GETTING WORSE”
by David Schechter, Haley Rush, and Chance Horner

[This report on light pollution (the target of the embedded link above) is also from CBS News, broadcast on 1 September 2023.]

America’s rapid adoption of LED lighting saves money and uses less electricity. But it’s also making it harder to see the stars. 

Light pollution comes from excessive artificial light that causes the sky to glow and obscures the light of the stars, and the problem is growing fast. New research in the journal Science found the night sky is getting 10% brighter every year.  

Experts say much of that light pollution is driven by the growth of cheaper, cleaner and brighter LED lighting. 

“The most common kinds you see, the sort of bright white ones, are absolutely making the problem much worse,” said Stephen Hummel, the dark skies senior outreach coordinator at the University of Texas’ McDonald Observatory. 

A light pollution map of the United States shows the widespread nature of the problem. The eastern half of the United States is almost entirely blanketed by some level of light pollution. And while the night sky is hardest to see in big cities, the view of the night sky is also degraded in suburban and rural areas. 

“(Light) basically gets reflected from the sky and creates what we call air glow,” said Ohad Shemmer, an astronomer at the University of North Texas, who studies black holes. “The Milky Way is gradually disappearing from view. Many of the fainter stars are disappearing.”

Government regulation is driving the rapid switch to LEDs. In 2007, Congress mandated that all lightbulbs be three times more efficient. That policy finally took effect on August 1 of this year [2023], effectively banning new incandescent light bulbs in favor of LEDs and compact fluorescents.  

But there are unintended consequences. 

Research shows too much light at night can interrupt our sleep cycle, potentially contributing to health issues like certain cancers and heart problems. It’s also a major factor in the decline of insect populations which require darkness to navigate, and it contributes to the death of hundreds of millions of birds each year that fly into brightly lit buildings.   

The McDonald Observatory is in the Big Bend region of far West Texas. It’s home to the Hobby-Eberly Telescope, the largest of its kind in the world. At night it collects the faint lights of outer space on an exceptionally large mirror. A dark night sky is essential to that work. 

“If the sky got too bright, eventually there would be no point in building big telescopes on the ground at all,” said astronomer Steven Janowiecki, who is the telescope’s science operations manager. 

To protect the night sky, the Observatory helped organize the Greater Big Bend International Dark Sky Reserve. It covers an area of 15,000 square miles across West Texas and portions of northern Mexico. The certification is granted by the nonprofit DarkSky, which has more than 70 chapters across the country. 

The reserve is a partnership of parks, communities and local groups that have all agreed to better lighting practices by swapping out their bright white LED streetlights for amber-colored ones that do not scatter as much light up into the sky and by installing covers that point light downward. 

The Alpine [Texas] City Council unanimously passed an ordinance in 2021 regulating outdoor lighting. Nearly all the city’s 200 streetlights have been updated from white to amber. The ordinance gives businesses and homes 5 years to convert to dark sky friendly lighting or face a daily fine of $50. 

“[Dark skies are] our product,” said Chris Ruggia, the director of tourism for the City of Alpine. “It’s the experience of coming here, and if we want that to continue, to provide some kind of prosperity in the community, we have to take care of it.”  

Ruggia says there are local programs to help homeowners cover the associated costs of making the switch and that there has been little controversy around the mandate. But he anticipates that might change as the deadline approaches. 

“There’s going to be some conversations that aren’t easy, especially as the time limit runs out,” he said. 

The American Lighting Association, which represents lighting manufacturers, acknowledges the problem of light pollution is “more extensive than originally thought.”  In response, it says many of its manufacturers now make shielded outdoor light fixtures to direct light away from the sky. 

Light pollution readings taken across the reserve show the plan is working. Astronomer Stephen Hummel says there has been a 20% reduction in nighttime light pollution there since 2020.  

But it is not just small communities that are making an impact. Hummel points to big cities like Los Angeles, Chicago and Phoenix that are all swapping out overly bright streetlights for ones that are dark sky friendly. 

“The problem really is not money. It isn’t infrastructure, really. It’s awareness. Light pollution is completely reversible. It’s one of the few kinds of pollution that you could solve immediately. You could flip a switch and fix the problem,” he said. 

[U.S. Dark Sky Places: There are approximately 165 International Dark Sky Places — sanctuaries for natural darkness designated by the DarkSkyInternational (formerly International Dark-Sky Association) — across the United States.  In these places, you can often find exceptionally clear views of the night sky.

[Haley Rush is an Investigative Producer for CBS News & Stations/Local News Innovation Lab.  She brings experience from previous roles at KPTV Fox 12 Oregon (Portland), KRQE NEWS 13/KASA FOX 2 (Albuquerque/Santa Fe, New Mexico), and KPLC-TV (Lake Charles, Louisiana).  Rush holds a 2013 Bachelor of Arts degree in Broadcast Journalism from Mayborn School of Journalism – University of North Texas in Denton, Texas.  

[Chance Horner is a photojournalist and producer covering climate change and the environment for CBS News.]

*  *  *  *
“RAPID BRIGHTENING OF NIGHT SKIES GLOBALLY:
RECENT RESULTS FROM CITIZEN SCIENCE AND SOLUTIONS”

[This article was posted to the website of the American Astronomical Society on 1 March 2023.  It’s somewhat technical, and the references are mostly from scientific journals, so I've included the list of sources, which I would ordinarily omit, below the article itself.  (Most of the references are likely to be in university libraries or the public systems of large cities, rather than local community libraries.  I see, however, that all have URL’s noted in the citations below, so there may be online editions accessible—though some may limit access in one way or another.)]

A recent paper by Kyba et al. (2023) [this is a link to the Science article referenced in the report above] found that light pollution of the world’s night skies has increased by as much as 10% a year since 2011, based on star counts made by citizen scientists. Paraphrasing the authors, night skies would brighten by a factor of about four over the duration of human childhood, strongly reducing the visibility of stars. This has been widely covered in the media and articles. Here, we share an overview of these results, related consequences, and one ray of hope: ground-based light pollution can be addressed through mitigating solutions that have already been successfully demonstrated.

[A citizen scientist is a member of the general public—an amateur or nonprofessional researcher—who voluntarily participates in scientific work (i.e., citizen science, also known as community science or participatory science), often in collaboration with or under the direction of professional scientists and scientific institutions.]

Although our newsfeeds and attention are dominated by SpaceX Starlink launches and the impact on astronomy from low-earth orbiting satellites, ground-based light pollution remains the largest threat to astronomical science and to humanity’s relationship with the skies. The recent citizen-science analysis in Kyba et al. 2023 revealed that terrestrial light pollution has not gone away and is, in fact, increasing faster than expected, by as much as 10% each year over the previous year. Although even this is likely an underestimate, there is some good news: ground-based light pollution can be mitigated successfully.

Skyglow — the most familiar symptom of light pollution — is caused by atmospheric scattering of light from ground-based sources (direct or reflected). Short wavelengths are scattered most effectively leading to the familiar light domes and distinctive glow that yield a washed-out appearance to the skies above light-polluted regions at night. Anyone who has frequented a major metropolitan area well knows that seeing more than a handful of stars is rare. And as astronomers, we’re all familiar with the forlorn husks of once-productive research facilities now stranded amongst bustling, brightly lit city streets or university campuses.

As the global population continues to grow and cities expand, the problem of light pollution grows and expands with them. This seems like a faraway concern for most astronomical sites these days, with the largest telescopes being built in remote regions of the planet with little light pollution to worry about, for now. However, with growth rates as high as 10% per year, the impact of light pollution poses an increasing problem for our science.

Light pollution isn’t just bad for our astronomical sites. How many astronomers were motivated to consider an astronomy career by childhood experiences of the night sky or an astronomical event (Comet Hale-Bopp, anyone?)? As fewer and fewer people are able to experience the night sky, we lose the inspiration that drives our science, something that makes astrophysics one of the easiest physical sciences to "sell" to the public and that brings talented engineers to our field to design and run our facilities.

[Comet Hale-Bopp, formally designated C/1995 O1, last appeared over Earth in 1997. It’s predicted to appear next in about 4385 (2,360 years from now).]

Beyond these human concerns, there is increasing evidence that ground-based light pollution is responsible for disruption to human and animal circadian rhythms (Cao et al. 2023, Touzot et al. 2023), migratory patterns (Torres et al. 2020), and plant seasonal cycles (Meng et al. 2022), as well as changes in reproductive cycles of insects (Firebaugh & Haynes 2016) to name a few of the problems. It may also make urban air quality worse (Stark et al. 2011, Shith et al. 2022). Poor-quality outdoor lighting, which is the source of light pollution, wastes energy (Tatro 2020) and is in part responsible for workplace accidents (Wren & Locke 2015). So, even if your own scientific endeavors are not impacted by ground-based light pollution, it is highly likely that your life or environment is.

[The circadian rhythm is the natural, internal process that regulates the physical, mental, and behavioral changes an organism experiences over a roughly 24-hour cycle. The word ‘circadian’ comes from the Latin circa diem, meaning ‘about a day.’

[This “internal clock” is found in most living things, including humans, animals, plants, and microorganisms. It’s primarily influenced by light and darkness and regulates important functions like sleep-wake cycles, body temperature, hormones, and digestion.

[Disruptions to the circadian rhythm (e.g., from jet lag or shift work) can negatively impact health and well-being, leading to sleep disorders, fatigue, and an increased risk of other health issues like obesity and depression.]

For more than a decade, NSF’s [National Science Foundation] National Optical-Infrared Astronomy Research Laboratory (NOIRLab) has been leading a citizen-science program known as the Globe at Night. This program collects estimates of naked-eye limiting magnitude (NELM) and Sky Quality Meter measurements submitted by volunteers around the world. Contributions typically exceed some 10,000 to 30,000 observations per year with more than a quarter of a million data points from 180 countries over the last 17 years.

[NELM is the magnitude of the faintest star you can see with your unaided eyes in a particular night sky. It varies depending on factors like light pollution, atmospheric conditions, and your own vision, but is a common way to measure the darkness of the sky. A lower number for limiting magnitude means a darker sky where fainter stars are visible.

[Sky Quality Meter (SQM) measurements quantify the brightness of the night sky in a specific area. This measurement is typically taken in “magnitudes per square arcsecond” (mag/arsec²) using a portable device, with lower numbers indicating a darker sky. These measurements are used to monitor light pollution, with data collected by amateur astronomers and researchers worldwide.]

Kyba et al. (2023) studied the NELM estimates and based on these data inferred a global average increase in the light pollution of 9.6% (10.4% in North America) per year between 2011 and 2022. This is a much larger increase than has been reported by studies using only satellite remote sensing observations of light emissions (Kyba et al. 2017, Sanchez de Miguel 2017), which had found a roughly 2% per year increase on a global average basis. Satellite instrumentation is focused on wavelengths of 500-900 nm [nanometer, a unit of length equal to one billionth of a meter commonly used to express the very tiny dimensions of electromagnetic radiation], which misses short-wavelength optical emissions characteristic of modern white light-emitting diodes (LEDs) that increasingly dominate the light budgets of cities. In addition, blue light (i.e., shorter wavelengths) is more effectively scattered in the atmosphere than other colors. These two effects give a possible reason for the lower estimate from orbital-based light pollution measures versus the ground-based estimates studied by Kyba et al. The team also points out that direct glare from poorly shielded LED street lights could blind observers near them to faint stars, biasing the NELM estimates toward brighter values without increasing skyglow locally (Bará, Bao-Varela & Kocifaj 2023).

It is probable that the global average change of +9.6% per year is in fact an underestimate of the true rate of increase in light pollution. Since artificial nighttime lighting is strongly correlated with economic performance metrics (Rybnikova 2022) and regions with high rates of economic growth are under-sampled in the Globe At Night data, it is likely that the true rate of increase exceeds 10% per year.

For our work as astronomers, this means that skies over existing observatories are getting noticeably degraded over timescales far less than one astronomer's lifetime, and the options available for sufficiently dark locations for new observatories are dwindling rapidly. This finding also demonstrates (as the authors note) that existing lighting policies are not adequate for the protection of the night sky.

There is, however, some good news — the sky glow from artificial light at night can be reduced. The strategies for cutting light pollution are straightforward: use outdoor lighting only when, where, and how it is needed (timing, area, and brightness), minimize blue light content, and use fully shielded fixtures (see Outdoor Lighting Basics for more information). Those approaches may be simple, but as the Kyba et al. study shows, more effort is needed to put these recommendations into ordinances, bylaws, and other regulations to reverse the degradation of our shared night sky, which is a millennia-old resource and inspiration for us all.

Please join us at AAS 242 in Albuquerque to hear about recent successes in mitigating light pollution, the creation of protected dark-sky places, recent documentaries on the many ways we connect to dark skies, and how good lighting practices have been implemented in lighting ordinances in different regions of the US. [This meeting of the American Astronomical Society took place on 4-8 June 2023.]

References:

•   Bará, S., Bao-Varela, C., & Kocifaj, M. 2023. “Modeling the artificial night sky brightness at short distances from streetlights”. Journal of Quantitative Spectroscopy and Radiative Transfer, vol. 296, 108456. https://doi.org/10.1016/j.jqsrt.2022.108456 

•   Cao, M., Xu, T., & Yin, D. 2023. “Understanding light pollution: Recent advances on its health threat and regulations” Science Direct, vol 127, 589-602. https://doi.org/10.1016/j.jes.2022.06.020

•   Firebaugh, A. & Haynes, K. J. 2016. “Experimental tests of light-pollution impacts on nocturnal insect courtship and dispersal” Oecologia, 182, 4, 1203-1211. https://doi.org/10.1007/s00442-016-3723-1

•   Kyba, C. C. M., Kuester, T., Sanchez de Miguel, A., et al. 2017. “Artificially lit surface of Earth at night increasing in irradiance and extent” Science Advances, vol 3, 11. https://doi.org/10.1126/sciadv.1701528

•   Kyba, C. C. M., Altintas, Y. O., Walker, C.E., et al. 2023. “Citizen scientists report global rapid reductions in the visibility of stars from 2011 to 2022” Science, vol. 379, 6629, 265-268. DOI: 10.1126/science.abq778

•   Meng, L., Zhou, Y., O Roman, M., et al. 2022. “Artificial light at night: an underappreciated effect on phenology of deciduous woody plants” PNAS Nexus, vol 1, 2, pgac046. https://doi.org/10.1093/pnasnexus/pgac046

•   Rybnikova, N. 2022. "Everynight Accounting: Nighttime Lights as a Proxy for Economic Performance of Regions" Remote Sensing vol. 14,  4, 825. https://doi.org/10.3390/rs14040825

•   Sanchez de Miguel, A., Aube, A., Zamorano, J., et al.  2017. “Sky Quality Meter measurements in a colour- changing world” MNRAS, vol. 467, 3, 2966-2979. https://doi.org/10.1093/mnras/stx145

•   Shith, S., Ramli, N. A., Awang, N. R., Ismail, M. R., Latif, M. T., & Zainordin, N. S. 2022. “Does Light Pollution Affect Nighttime Ground-Level Ozone Concentrations?” Atmosphere, vol. 13, 11, 1844. https://doi.org/10.3390/atmos13111844 

•   Stark, H., et al. 2011. “City lights and urban air”. Nature Geoscience, vol. 4, 11, 730–731. https://doi.org/10.1038/ngeo1300

•   Tatro, K., 2020. “Light Energy: Our Wasted Resource” Consilience, vol. 22, 65-72. https://doi.org/10.7916/consilience.vi22.6731

•   Torres, D., Tidau, S., Jenkins, S., et al. 2020. “Artificial skyglow disrupts celestial migration at night” Current Biology, vol 30, 12, R696-R697. https://doi.org/10.1016/j.cub.2020.05.002

•   Touzot, M., Dumet, A., Secondi, J., et al. 2023. “Artificial light at night triggers slight transcriptomic effects on melatonin signaling but not synthesis in tadpoles of two anuran species” Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 111386. https://doi.org/10.1016/j.cbpa.2023.111386

•   Wren, W., & Locke, S. 2015. “Upgraded Rig Lighting Improves Night Time Visibility While Reducing Stray Light and the Threat to Dark Skies in West Texas” SPE E&P Health, Safety, Security and Environmental Conference – Americas” March 2015. https://doi.org/10.2118/173492-MS

 

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).]