Stonehenge, a world-renowned prehistoric monument located in England, holds the power and mystery of humanity's relationship to the cosmos, in particular, the sun.

In 2001, Neil deGrasse Tyson -- director of the American Museum of Natural History and narrator of the television series "Cosmos: A Spacetime Odyssey" -- introduced the world to Manhattanhenge.

At Stonehenge, great stones frame the rising sun on the summer solstice. This week, on Friday and Saturday, closer to home, New York City beckons us to witness the setting sun perfectly framed by high-rise buildings and skyscrapers at the end of every numbered street of the city's grid layout. Numbered streets run east to west from the East River to the Hudson. Sunlight will blaze and glow in the channels created by buildings on either side of the street. There's a May date for the same phenomenon. This year's was May 28 and 29.

On Friday, at 8:28 p.m., the full orb of the sun will be poised on the horizon at the far edge of the corridor created by buildings. On the Saturday, according to Tyson, the sunset is most precisely aligned with the city's street grid and so is the summer date of Manhattanhenge this year. The view will be of half the disk above and half below the horizon as it goes down at 8:25.

Tyson writes, on the AMNH website, "Arrive a half-hour earlier than the times given. ... For best effect, position yourself as far east in Manhattan as possible. But ensure that when you look west across the avenues you can still see New Jersey. Clear cross streets include 14th, 23rd, 34th, 42nd, 57th, and several streets adjacent to them. The Empire State building and the Chrysler building render 34th street and 42nd streets especially striking vistas."

A double bill is set for Saturday. The Full Thunder Moon rises nearly opposite the phenomenal sunset, in the east-southeast, at 8:27 p.m. Let's go!

To contact Judy Isacoff, M.A. go to: www.naturesturn.org