Manhattanhenge

Manhattanhenge
Name	Manhattanhenge
Caption	Sunset alignment on Manhattan street grid
Location	Manhattan, New York City, United States
Established	1990s
Type	Urban astronomical alignment

Manhattanhenge Manhattanhenge is a timed solar alignment event when the setting or rising Sun aligns with the orthogonal avenues of Manhattan's street grid. Observers assemble along corridors such as Broadway and 42nd Street to view the phenomenon, attracting residents, tourists and photographers from across New York City and beyond.

Overview

Manhattanhenge occurs twice each year for both sunset and sunrise when the ecliptic position of the Sun matches the azimuth of Manhattan's orthogonal avenues laid out in the Commissioners' Plan of 1811. The effect produces a dramatic glowing disc framed by the rectangular canyon of midtown skyscrapers including landmarks such as Chrysler Building, Empire State Building, and views toward Hudson River or East River depending on the date and precise street. Public interest links the event to civic culture in Manhattan, urban planning histories like the Commissioners' Plan of 1811, and seasonal events such as Summer solstice and Winter solstice.

Astronomy and alignment

The alignment arises from Manhattan's grid rotation of approximately 29.0 degrees east of true north established by the Commissioners' Plan of 1811. Solar azimuths on specific dates intersect that rotation when the geocentric ecliptic longitude of the Sun produces a sunset or sunrise vector parallel to the avenues. Calculations invoke spherical astronomy parameters used in observatories such as Columbia University Observatory and reference systems including the International Celestial Reference Frame. Predictions account for atmospheric refraction near the horizon and the equation of time from Kepler's laws and Newtonian mechanics. The dates shift slightly with leap years and the Gregorian calendar rules established by Pope Gregory XIII; the phenomenon is related to but distinct from alignments celebrated at sites like Stonehenge and astronomical alignments in Mesoamerica.

History and cultural significance

Awareness of the alignment predates the popular name and was noted by urbanists and astronomers studying the Commissioners' grid; the coinage of the term occurred in the 1990s and proliferated through columns in outlets such as The New York Times and features on National Public Radio. Manhattanhenge became integrated into New York cultural life alongside annual parades like the Macy's Thanksgiving Day Parade and public gatherings at venues like Times Square. Its cultural resonance connects to the work of planners and cartographers involved in Manhattan development including figures associated with the Grid plan and institutions such as New York City Department of City Planning. Photographers, tourists, and scholars reference the event in guidebooks by publishers like Lonely Planet and in broadcasts on networks including NBC and CNN.

Observation events and viewing locations

Prime public viewing locations include wide east–west streets such as 14th Street, 23rd Street, 34th Street adjacent to Herald Square, and 42nd Street near Bryant Park and Times Square. Observers gather on terraces near institutions like The High Line and along waterfront promenades at Battery Park City for alternative sightlines. Transit access from hubs including Penn Station, Grand Central Terminal, and Fulton Street allows large crowds. Municipal responses have involved coordination among New York City Police Department, New York City Department of Transportation, and local community boards to manage pedestrian safety on arterial streets and during events promoted by organizations such as the American Astronomical Society and university outreach programs from New York University and Columbia University.

Photography and popular media

Photographers exploit the event's symmetry and backlighting to produce silhouettes of landmarks like One World Trade Center and the Metropolitan Life Insurance Company Tower. Coverage appears in photo agencies such as Getty Images and editorial outlets including Time (magazine), The Guardian, and BBC News. The alignment is featured in films, television episodes, and social media channels on platforms including Instagram, YouTube, and Twitter where citizen photographers tag images alongside accounts for institutions like Museum of Modern Art and travel guides by Fodor's. Techniques discussed in workshops at organizations such as the International Center of Photography emphasize exposure bracketing, use of telephoto lenses, and timing to account for solar motion and urban silhouette contrast.

Scientific analysis and related phenomena

Scientific interest treats Manhattanhenge as an applied case of urban heliophany studied alongside solar alignments at archaeological sites like Chaco Canyon and Stonehenge. Researchers model sightlines with geographic information systems employed by agencies such as the United States Geological Survey and academic departments at Columbia University and New York University. Studies consider urban canyon effects on irradiance, shadow casting by skyscrapers including Woolworth Building, and seasonal insolation patterns relevant to urban climatology scholars in institutes like the Rockefeller University and environmental programs at City University of New York. Related phenomena include the "double sunset" effect observed in other cities with regular grids, solstitial sunrises studied at Glastonbury Tor, and contemporary phenomena such as equinox alignments promoted by astronomical societies including Royal Astronomical Society.

Category:New York City events Category:Astronomical events