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NASA Moon Data ~ August 21, 2017 Eclipse

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NASA Moon Data Provides More Accurate 2017 Eclipse Path

https://www.nasa.gov/feature/goddard/2017/nasa-moon-data-provides-more-accurate-2017-eclipse-path

On Monday, Aug. 21, 2017, millions in the U.S. will have their eyes to the sky as they witness a total solar eclipse. The moon’s shadow will race across the United States, from Oregon to South Carolina. The path of this shadow, also known as the path of totality, is where observers will see the moon completely cover the sun. And thanks to elevation data of the moon from NASA’s Lunar Reconnaissance Orbiter, or LRO, coupled with detailed NASA topography data of Earth, we have the most accurate maps of the path of totality for any eclipse to date.

 

By bringing in a variety of NASA data sets, visualizer Ernie Wright has created a new and more accurate representation of the eclipse.
 

Early map-making

Eclipse maps have long been used to plot the predicted path of the moon’s shadow as it crosses the face of Earth. Friedrich Wilhelm Bessel and William Chauvenet, two prominent 19th century astronomers and mathematicians, developed the math still used to make eclipse maps — long before computers and the precise astronomical data gathered during the Space Age.

Traditionally, eclipse calculations assume that all observers are at sea level and that the moon is a smooth sphere that is perfectly symmetrical around its center of mass. The calculations do not take into account different elevations on Earth and the moon’s cratered, uneven surface.

Map of US with shadow line northwest to southeast
A map of the United States showing the path of totality for the August 21, 2017 total solar eclipse.
Credits: NASA/Goddard/SVS/Ernie Wright
 
For slightly more accurate maps, people use elevation tables and plots of the lunar limb — the edge of the visible surface of the moon as seen from Earth. Until recently, astronomers have used the limb profiles published in 1963 by astronomer Chester Burleigh Watts to create eclipse maps of the moon’s path of totality. To produce his profiles, Watts designed a machine that traced 700 photographs covering every angle of the moon visible from Earth.

However, eclipse calculations have gained even greater accuracy based on topography data from LRO observations.

 

A new look at an ancient phenomenon

Using LRO elevation maps, NASA visualizer Ernie Wright at Goddard Space Flight Center in Greenbelt, Maryland, created a continuously varying lunar limb profile as the moon’s shadow passes over the United States as it will during the upcoming eclipse. The mountains and valleys along the edge of the moon’s disk affect the timing and duration of totality by several seconds. Wright also used several NASA data sets to provide an elevation map of Earth so that eclipse observer locations were depicted at their true altitude.

The resulting visualizations show something never seen before: the true, time-varying shape of the moon’s shadow, with the effects of both an accurate lunar limb and the Earth’s terrain.

“We couldn’t have done visualizations like this even 10 years ago,” Wright said. “This is a confluence of increasing computing power and new datasets from remote sensing platforms like LRO and the Shuttle Radar Topography Mission.”

The lunar umbra is the part of the moon’s shadow where the entire sun is blocked by the moon. On an eclipse map, this tells you where to stand in order to experience totality. For centuries, eclipse maps have depicted the shape of the moon’s umbra, or darkest part of its shadow, as a smooth ellipse.

As evidenced in the new visualizations, the umbral shape is dramatically altered by both the rugged lunar terrain and the elevations of observers on Earth.

“We’ve known for a while now about the effects of the lunar limb and the elevation of observers on the Earth, but this is the first time we’ve really seen it in this way,” Wright said. “I think it’ll change how people think about mapping eclipses.”

Map of Pacific Northwest with eclilpse detail
This map shows a detailed image of the Moon's umbral shadow as it passes over the United States during the August 21, 2017 total solar eclipse.
Credits: NASA/Goddard/SVS/Ernie Wright
 

The true shape of the umbra is more like an irregular polygon with slightly curved edges. Each edge corresponds to a single valley on the lunar limb, the last spot on the limb that lets sunlight through. As these edges pass over mountain ranges, they are scalloped by the peaks and valleys of the landscape. The moon’s umbra will cross the Cascades, Rockies and Appalachians during the 2017 eclipse.

“Solar and lunar eclipses provide an excellent opportunity to talk about the moon, since without the moon there would be no eclipses,” said Noah Petro, deputy project scientist for LRO. “Because we know the shape of the moon better than any other planetary body, thanks to LRO, we can now accurately predict the shape of the shadow as it falls on the face of the Earth. In this way, LRO data sheds new light on our predictions for the upcoming eclipse.”

The total solar eclipse on Monday, Aug. 21, 2017 will cross the continental United States beginning in Oregon and ending in South Carolina. The last time a total solar eclipse spanned the United States was in 1918, when the path of totality entered through the southwest corner of Washington and passed over Denver, Colorado, Jackson, Mississippi, and Orlando, Florida before exiting the country at the Atlantic coast of Florida.

For more information about the upcoming 2017 solar eclipse, visit:
https://eclipse2017.nasa.gov
or
https://www.nasa.gov/eclipse

More information on the numerous NASA data sets incorporated into this visualization:
Blue Marble Next Generation was used for color of the land.
Shuttle Radar Topography Mission was used for Earth elevations.  This is a global elevation map based on a radar instrument flown on Space Shuttle Endeavour during STS-99 in February 2000.
Lunar Digital Elevation Model  and  Selene/LRO Digital Elevation Model were used for the lunar limb.
NASA's Jet Propulsion Laboratory's DE421 provided Earth, moon, and sun positions.


By Sarah Schlieder

NASA's Goddard Space Flight Center in Greenbelt, Md.

Last Updated: Jan. 5, 2017
Editor: Karl Hille
 
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BEER-----> You can't get a room in the 'Path' - I'm told.

BELCH

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EARTH----->  I read that too.  Here in Oklahoma City we will get a partial view.

NUTsy

 

Image result for oklahoma view of eclipse

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I am just hoping for a sunny day.  I have seen many partial eclipse and one close enough to be a total....   the effect is really strange and beautiful !

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Yeah, I'm hoping for clear skies myself.

Illinois will see a total only at the Southern edge of the state.  The rest of the state will be like here, a partial, but I'm betting your partial will be better than my partial.

 

Image result

 

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https://www.nasa.gov/press-release/nasa-recommends-safety-tips-to-view-the-august-solar-eclipse

July 21, 2017
RELEASE 17-063

NASA Recommends Safety Tips to View the August Solar Eclipse

A total solar eclipse, which is when the Moon completely covers the Sun, will occur across 14 states in the U.S. on Aug 21, 2017

 

Quote

More than 300 million people in the United States potentially could directly view the Aug. 21 total solar eclipse, and NASA wants everyone who will witness this celestial phenomenon to do so safely.

 

That Monday, a partial eclipse will be visible in every state. A total solar eclipse, which is when the Moon completely covers the Sun, will occur across 14 states in the continental U.S. along a 70-mile-wide (112-kilometer-wide) swath of the country.

 

It’s common sense not to stare directly at the Sun with your naked eyes or risk damaging your vision, and that advice holds true for a partially eclipsed Sun. But, only with special-purpose solar filters, such as eclipse glasses or a handheld solar viewer, you can safely look directly at the Sun. 

 

NASA recommends that people who plan to view the eclipse should check the safety authenticity of viewing glasses to ensure they meet basic proper safety viewing standards.

 

Eclipse viewing glasses and handheld solar viewers should meet all the following criteria:

 

·      Have certification information with a designated ISO 12312-2 international standard

·      Have the manufacturer’s name and address printed somewhere on the product

·      Not be used if they are older than three years, or have scratched or wrinkled lenses

·      Not use homemade filters

·      Ordinary sunglasses -- even very dark ones -- should not be used as a replacement for eclipse viewing glasses or handheld solar viewers

 

“While NASA isn’t trying to be the eclipse safety glasses ‘police,’ it’s our duty to inform the public about safe ways to view what should be a spectacular sky show for the entire continental United States,” said Alex Young, associate director for science in the Heliophysics Science Division at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “It’s important that individuals take the responsibility to check they have the proper solar eclipse viewing glasses. With the eclipse a month away today, it’s prudent to practice ahead of time.”

 

An alternative method for safe viewing of the partially-eclipsed Sun is with a pinhole projector. With this method, sunlight streams through a small hole – such as a pencil hole in a piece of paper, or even the space between your fingers – onto a makeshift screen, such as a piece of paper or the ground. It’s important to only watch the screen, not the Sun. Never look at the Sun through the pinhole -- it is not safe.

 

NASA has coordinated with medical and science professionals to provide additional safety information. For details, visit:

 

https://eclipse2017.nasa.gov/safety

 

More than 6,800 libraries across the U.S. are distributing safety-certified glasses. Many are working with scientists to hold viewing events and activities before and during the eclipse. For a listing of participating libraries, visit:

 

https://www.starnetlibraries.org/2017eclipse

 

NASA Television is offering a special live program, “Eclipse Across America: Through the Eyes of NASA” with real-time coverage of the event from coast to coast. The nearly four-hour program will include unprecedented images of the Aug. 21 eclipse from numerous spacecraft -- including the International Space Station – high-altitude aircraft and balloons, and ground observations. Each will offer a unique vantage point for the eclipse. Additionally, the broadcast will include live coverage of activities in parks, libraries, stadiums, festivals and museums across the nation, and on social media. To watch the Aug. 21 NASA TV eclipse broadcast online and access interactive web content and views of the eclipse from these assets, visit:

 

https://www.nasa.gov/eclipselive

 

-end-

Dwayne Brown / Laurie Cantillo
Headquarters, Washington
202-358-1726 / 202-358-1077
dwayne.c.brown@nasa.gov / laura.l.cantillo@nasa.gov

 

Karen Fox
Goddard Space Flight Center, Greenbelt, Md.
301-286-6284
karen.c.fox@nasa.gov
Last Updated: July 21, 2017
Editor: Katherine Brown

 

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every eclipse some fools still don't get the message and damage their eyes ! 

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