The event has been dubbed "Manhattanhenge" for the way it turns New York City into a Stonehenge-like sun dial.
The sun sets perfectly in line with the Manhattan street grid twice a year, explains astrophysicist Neil deGrasse Tyson on the Hayden Planetarium website.
Here are the best viewing times for Manhattanhenge 2012:
May 29 at 8:17 p.m. EDT
July 12 at 8:25 p.m. EDT
There are two other days when the sun isn't perfectly aligned with the grid, but still puts on a show. On these two days, May 30 and July 11 this year, you see a full sun sitting on the horizon when looking down the cross streets, rather than the half orb. Here are the best times to catch the full sun setting on New York City:
May 30 at 8:16 p.m. EDT
July 11 at 8:24 p.m. EDT
The best way to watch Manhattanhenge, Tyson says, is to get as far east as possible on one of the city's major cross streets, such as 14th, 23rd, 34th, 42nd or 57th streets, and look west toward New Jersey. (The streets immediately adjacent to these wide cross streets will work fine, too, but the view won't be quite as stunning.) Standing on 34th or 42nd street provides a particularly nice view, as the views include the Empire State Building and the Chrysler Building. It's a good idea to get to your spot 30 minutes early, so you can beat out the other sun worshippers. [Do Sunrises Look Different from Sunsets?]
Not in New York? Tyson notes that any city crossed by a rectangular grid will experience days when the setting sun aligns with their streets. However, a closer look at such cities around the world shows most are less than ideal for this purpose, because they don't have a clear westward view to the horizon, as Manhattan has across the Hudson River to New Jersey.
"So Manhattanhenge may just be a unique urban phenomenon in the world," he said, "if not the universe."
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