Tonight: Manhattanhenge

Tonight is Manhattanhenge, the twice-a-year alignment of the setting sun with the street grid of Manhattan.

On Sunday, May 31, the entire solar sphere will be visible just above the horizon at 8:17 p.m. EDT. The second opportunity comes later in the summer, with another half-sphere sunset on Sunday, July 12, at 8:25 p.m. EDT and a whole-sphere viewing on Saturday, July 11, at 8:25 p.m. EDT. These times are calculated every year by the astronomer Neil deGrasse Tyson, director of the Hayden Planetarium in New York, who coined the term "Manhattanhenge." The "henge" comes of course from Stonehenge, the prehistoric monument in the Salisbury plains of England. The large structure of stones and earthen mounds is thought to be a burial ground that was oriented to face the midsummer sunrise and midwinter sunset.

Viewing parties are scheduled at the east ends of 34th and 42nd streets.