Friday, July 14, 2017

Total Solar Eclipse 2017 Guide and Map (Farmer's Almanac)

WHERE, WHEN, AND HOW TO WATCH THE TOTAL SOLAR ECLIPSE OF 2017

by Bob Berman

Prepare for the total solar eclipse of 2017—the first to appear over the mainland United States in nearly 40 years—with our viewing guide and eclipse path that shows the path of totality across the country.

WHAT IS A SOLAR ECLIPSE?

To the naked eye, the sky is an inverted bowl hosting thousands of glowing points and two disks. The points—stars and planets—exhibit no size because of their immense distance from Earth. The two disks are the Sun and Moon. By amazing coincidence, these disks appear exactly the same size. Why?

The Sun is 400 times larger than the Moon but also 400 times farther from Earth than the Moon. These facts allow the Moon to fit perfectly over the Sun's face to create a total eclipse. Yet, it's not so big that it blocks out the Sun's dramatic hot-pink corona or atmosphere and not so small that it leaves the Sun's blinding gas surface (photosphere) uncovered. This bizarre alignment does not hold for any other planet and will not last forever: The Moon is spiraling away from Earth like a skyrocket and gradually increasing its separation.

The perfect lineup of these two disks (Sun and Moon) to form a total solar eclipse does not happen often—just once every 360 years, on average, for any one point on Earth. (This is one reason why relatively few people have ever seen one.) The U.S.mainland is currently experiencing its longest totality drought in history. The last total solar eclipse occurred on February 26, 1979, over northwestern states and south central Canada.

This cycle of paucity finally ends with this year's total solar eclipse, taking place on August 21, 2017.

WHAT HAPPENS DURING A TOTAL SOLAR ECLIPSE?

For sheer visceral impact, a total solar eclipse is not even remotely comparable to a lunar eclipse, a partial solar eclipse, or even major auroral displays. A solar totality stands alone. If you are in the right place, it creates darkness in daytime along a 140-mile-wide ribbon of Earth. The brightest stars come out in midday but not as you might presume: During totality, they appear in seasonal reverse. In summer, the winter constellations emerge; during a winter solar totality, summer's stars appear.

And that's not all.

An uncommon mind-set takes over people when the Sun, Moon, and your spot on Earth form a perfectly straight line in space. Many observers shout and babble. Some weep. Afterward, everyone proclaims it to be the greatest spectacle they have ever beheld. Beyond that, many are speechless. (Animals also exhibit odd behavior, such as falling strangely silent.)

The experience surpasses all expectations and imaginings:

  • The eye sees the transition of the Moon over the Sun differently from photographs; because of under- or overexposure, a camera lens can not capture the same range of brightness as human vision.
  • The delicate tendrils of the Sun's corona splay into the surrounding sky in a manner wholly different from the way they appear in photos.
  • During the 10 minutes before and after totality, when the Sun is more than 80 percent eclipsed and its light arrives only from its edge, or limb, earthly colors turn richer and more saturated, while shadows become stark and oddly crisp—as if a different type of star is illuminating Earth.
  • As the Moon slides over the Sun, not only is light blocked in the ribbon of space, but solar heat is, too. The steady drop in temperature usually results in a haunting eclipse wind.
  • At 1 minute before and after totality, all white and light-color ground surfaces underfoot (sidewalks, sand, the like) suddenly exhibit shimmering shadow bands everywhere. (Think of black lines on the bottom of a swimming pool that appear to wiggle.) This eerie phenomenon can make your hair stand on end, yet it can not be captured on film. (Try it!) Recent research suggests that shadow bands are the edges of atmospheric temperature cells (air pockets) made visible by the remaining tiny point of Sun. Their motion catches the eye despite their extremely low contrast.

To witness these extraordinary phenomena, you need to be in totality's path (see map, below). This year, you can drive into it and watch from a roadside! Totality lasts longest—over 2 minutes—within the centerline of the ribbon. A partial eclipse will be visible outside of that ribbon, but the phenomena described above will not occur there.

Learn more about what makes this total solar eclipse so special: Planning for the Total Solar Eclipse 2017

THE SOLAR ECLIPSE'S PATH

To see if your town falls within the 2017 eclipse's path, check out NASA's Interactive Total Solar Eclipse Map, as well as the simplified version, below.


https://eclipse2017.nasa.gov/sites/default/files/eclipse_full_map.pdf

The perfect lineup of these two disks (Sun and Moon) to form a total solar eclipse does not happen often—just once every 360 years, on average, for any one point on Earth. (This is one reason why relatively few people have ever seen one.) The U.S.mainland is currently experiencing its longest totality drought in history. The last total solar eclipse occurred on February 26, 1979, over northwestern states and south central Canada.

This cycle of paucity finally ends with this year's total solar eclipse, taking place on August 21, 2017.

WHAT HAPPENS DURING A TOTAL SOLAR ECLIPSE?

For sheer visceral impact, a total solar eclipse is not even remotely comparable to a lunar eclipse, a partial solar eclipse, or even major auroral displays. A solar totality stands alone. If you are in the right place, it creates darkness in daytime along a 140-mile-wide ribbon of Earth. The brightest stars come out in midday but not as you might presume: During totality, they appear in seasonal reverse. In summer, the winter constellations emerge; during a winter solar totality, summer's stars appear.

And that's not all.

An uncommon mind-set takes over people when the Sun, Moon, and your spot on Earth form a perfectly straight line in space. Many observers shout and babble. Some weep. Afterward, everyone proclaims it to be the greatest spectacle they have ever beheld. Beyond that, many are speechless. (Animals also exhibit odd behavior, such as falling strangely silent.)

The experience surpasses all expectations and imaginings:

  • The eye sees the transition of the Moon over the Sun differently from photographs; because of under- or overexposure, a camera lens can not capture the same range of brightness as human vision.
  • The delicate tendrils of the Sun's corona splay into the surrounding sky in a manner wholly different from the way they appear in photos.
  • During the 10 minutes before and after totality, when the Sun is more than 80 percent eclipsed and its light arrives only from its edge, or limb, earthly colors turn richer and more saturated, while shadows become stark and oddly crisp—as if a different type of star is illuminating Earth.
  • As the Moon slides over the Sun, not only is light blocked in the ribbon of space, but solar heat is, too. The steady drop in temperature usually results in a haunting eclipse wind.
  • At 1 minute before and after totality, all white and light-color ground surfaces underfoot (sidewalks, sand, the like) suddenly exhibit shimmering shadow bands everywhere. (Think of black lines on the bottom of a swimming pool that appear to wiggle.) This eerie phenomenon can make your hair stand on end, yet it can not be captured on film. (Try it!) Recent research suggests that shadow bands are the edges of atmospheric temperature cells (air pockets) made visible by the remaining tiny point of Sun. Their motion catches the eye despite their extremely low contrast.

To witness these extraordinary phenomena, you need to be in totality's path (see map, below). This year, you can drive into it and watch from a roadside! Totality lasts longest—over 2 minutes—within the centerline of the ribbon. A partial eclipse will be visible outside of that ribbon, but the phenomena described above will not occur there.

Learn more about what makes this total solar eclipse so special: Planning for the Total Solar Eclipse 2017

THE SOLAR ECLIPSE'S PATH

To see if your town falls within the 2017 eclipse's path, check out NASA's Interactive Total Solar Eclipse Map, as well as the simplified version, below.


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