Monday, May 30, 2011

Manhattanhenge again and a PS

Website reader and old friend Mary Birchard wrote this morning to remind me of Mannhattanhenge. The sun will be right on target at 8:17 pm. Best viewing time tonight will be about 7:45. : Below, the annual clip from astrophysicist Neil DeGrasse Tyson's blog.


Sunset on the Manhattan Grid

by Neil deGrasse Tyson, © 2001-2011

Manhattan-henge: Sunset down 34th Street

Sunset looking down 34th Street. One of two days when the sunset is exactly aligned with the grid of streets in Manhattan. Photo ©Neil deGrasse Tyson, 2001.

What will future civilizations think of Manhattan Island when they dig it up and find a carefully laid out network of streets and avenues? Surely the grid would be presumed to have astronomical significance, just as we have found for the pre-historic circle of large vertical rocks known as Stonehenge, in the Salisbury Plain of England. For Stonehenge, the special day is the summer solstice, when the Sun rises in perfect alignment with several of the stones, signaling the change of season.

For Manhattan, a place where evening matters more than morning, that special day comes twice a year. For 2011 they fall on May 30th, and July 12th, when the setting Sun aligns precisely with the Manhattan street grid, creating a radiant glow of light across Manhattan's brick and steel canyons, simultaneously illuminating both the north and south sides of every cross street of the borough's grid. A rare and beautiful sight. These two days happen to correspond with Memorial Day and Baseball's All Star break. Future anthropologists might conclude that, via the Sun, the people who called themselves Americans worshiped War and Baseball.

For these two days, as the Sun sets on the grid, half the disk sits above and half below the horizon. My personal preference for photographs. But the day after May 30th (May 31), and the day before July 12 (July 11) also offer Manhattanhenge moments, but at sunset, you instead will find the entire ball of the Sun on the horizon.

Manhattanhenge: half sun on the grid

Mock-up of the half sun on the grid during Manhattanhenge.

PS Murray Head reminded me that there was a great Op-Ed piece in the NY Times on 5/28 of special interest to birdwatchers. Here's a link to it: