Solar Eclipse 2017

Get Ready for the 2017 Solar Eclipse

2017.06.21

On Monday, August 21, 2017, our nation will be treated to a total eclipse of the sun. The eclipse will be visible -- weather permitting -- across all of North America. The whole continent will experience a partial eclipse lasting two to three hours. Halfway through the event, anyone within a 60 to 70 mile-wide path from Oregon to South Carolina will experience a total eclipse. During those brief moments when the moon completely blocks the sun’s bright face for 2 + minutes, day will turn into night, making visible the otherwise hidden solar corona, the sun’s outer atmosphere. Bright stars and planets will become visible as well. This is truly one of nature’s most awesome sights. The eclipse provides a unique opportunity to study the sun, Earth, moon and their interaction because of the eclipse’s long path over land coast to coast. Scientists will be able to take ground-based and airborne observations over a period of an hour and a half to complement the wealth of data provided by NASA assets.
What determines when we have an eclipse?

2017.06.14

Why are eclipses rare? The moon's orbit wobbles. Sometimes the moon's shadow is too high above the Earth. Sometimes it is too low. Other times, it is just right.
2017 Eclipse and the Moon's Orbit

2015.09.09

Solar eclipses can only occur at New Moon, when the Moon is between the Earth and the Sun. But not every New Moon produces an eclipse. The Moon's orbit is slightly tilted, and as seen in this animation, the tilt causes the Moon's shadow to miss the Earth during most New Moons—about five out of six, in fact. As the Earth-Moon system orbits the Sun throughout the year, the Moon's orbital tilt changes direction relative to the Sun. Sometimes the up side of the orbit is facing the Sun, and sometimes the down side. Twice a year, for about a month, what's facing the Sun is the line dividing the up and down sides. This is the line of nodes, the intersection of the Earth-Moon plane and the ecliptic or Earth-Sun plane. A solar eclipse can only occur at a New Moon that falls within one of these month-long eclipse seasons. That's when the Moon is close enough to the ecliptic to actually come between the Earth and the Sun. In this animation, the olive-colored square represents the ecliptic plane, while the light blue circle shows the plane of the Moon's orbit. The darker half of the lunar orbit plane is below (south of) the ecliptic, and the dividing line between light and dark is the line of nodes. The radial grid on the lunar orbit plane is stationary relative to the stars. It appears to rotate because our point of view is fixed to the Earth-Sun line; we're following the Earth as it orbits the Sun. At first glance, the line of nodes appears to be tracking with the grid, but in reality it's slowly turning westward (clockwise), completing a full revolution in 18.6 years. Unlike most illustrations of this kind, the Earth and the Moon are to scale. The Sun is off-screen to the left, about 400 times farther than the Earth-Moon distance and roughly twice as big as the Moon's orbit.
2017 Eclipse: Earth, Moon and Sun

2015.10.20

A solar eclipse occurs when the Moon passes between the Sun and the Earth, casting its shadow on the Earth. The shadow comprises two concentric cones called the umbra and the penumbra. Observers on the Earth who are within the smaller, central umbra see the Sun completely blocked. Within the larger penumbra, the Sun is only partially blocked. In this animation, the Earth, Moon, Sun, and shadow cones are viewed through a telescopic lens on a virtual camera located far behind the Earth. Long focal lengths like the one used here appear to compress the distance between near and far objects. Despite appearances, the geometry of the scene is correct. The Moon's umbra cone is roughly 30 Earth diameters long, barely enough to reach the Earth, while the Sun is almost 400 times farther away. From this perspective, we see the night sides of both the Earth and the Moon. Solar eclipses can only occur during New Moon, when the entire Earth-facing side of the Moon is experiencing nighttime darkness.
2017 Eclipse Shadow Cones

2015.09.09

A solar eclipse occurs when the Moon's shadow falls on the Earth. The shadow comprises two concentric cones called the umbra and the penumbra. Within the smaller, central umbra, the Sun is completely blocked by the Moon, and anyone inside the umbra sees a total eclipse. Within the larger penumbra, the Sun is only partially blocked. In this animation, the umbra and penumbra cones are viewed through a telescopic lens on a virtual camera located far behind the Moon. Long focal lengths like the one used here appear to compress the distance between near and far objects. Despite appearances, the geometry of the scene is correct. The Earth is roughly 112 lunar diameters beyond the Moon, and the angle at the apex of the umbral cone is only about half a degree. From this point of view directly behind the Moon, the edges of the shadow cones look circular. The edge of the penumbra is outlined in yellow. It passes over all of North and Central America and the Amazon basin, as well as Greenland and the North Pole. Everyone there will see at least a partial eclipse. The path of the umbra (the small black dot) crosses the United States from Oregon to South Carolina.
Flying Around The Eclipse Shadow

2017.06.21

This visualization combines the views from several previous visualizations (#4390, #4321, and #4314) to create a continuous camera flight from the night side of the Earth to the day side, showing the relationship of the Earth, Moon, and Sun during the August 21, 2017 eclipse. It shows the direction of the Moon's motion and the Earth's rotation, the complete path of the umbra from the moment it touches down on the Earth until the moment it departs, and the true scale of the Earth-Moon system.
Eclipse Background

2017.07.17

Eclipses, whether solar or lunar, occur because of the periodic alignments of the sun, Earth, and moon. These three bodies, orbit in space in very predictable paths (yes, the sun orbits too. It orbits the galaxy once every 200 million years!). Ever since the days of Kepler and Newton, we have been able to predict the motion of planetary bodies with great precision. So, why do eclipses happen?
Solar eclipses happen when the moon moves between Earth and the sun. You might think that this should happen every month since the moon’s orbit, depending on how it is defined is between about 27 and 29 days long. But our moon’s orbit is tilted with respect to Earth’s orbit around the sun by about five degrees. Not much, you say? Yes, but the moon, itself, is only about ½ degree in width in the sky, about ½ the width of your pinky finger held at arm’s length. So, sometimes the moon misses too high and sometimes too low to cause a solar eclipse. Only when the sun, moon, and Earth line up close to the “line of nodes”, the imaginary line that represents the intersection of the orbital planes of the moon and Earth, can you have an eclipse.
This is true for both solar and lunar eclipses. This situation is somewhat unique as no other moon in the solar system orbits roughly in the plane of the “ecliptic”, Earth’s orbital plane, that the planets more or less follow.
The Moon's Role in a Solar Eclipse

2017.07.21

While the sun is the main focus of a solar eclipse, our moon plays the most crucial role in creating this unique event. This video tutorial explains what happens during a total solar eclipse and a partial eclipse and how often they both occur. The video also explains how a solar eclipse differs from a lunar eclipse, and gives a helpful tip on how to remember the difference. In addition, the video examines how the two parts of the moon’s shadow, the umbra and penumbra, affect how we see an eclipse on the Earth, and illustrates the surprising true shape of the umbra. The video concludes by highlighting how data from NASA’s Lunar Reconnaissance Orbiter has helped us better map a solar eclipse’s path of totality. Visualizations included in this piece showcase the August 21, 2017 total solar eclipse happening in the United States.

2017 Eclipse Path

Narrated Video - Tracing the 2017 Solar Eclipse

2016.12.14

When depicting an eclipse path, data visualizers have usually chosen to represent the moon's shadow as an oval. By bringing in a variety of NASA data sets, visualizer Ernie Wright has created a new and more accurate representation of the eclipse. For the first time, we are able to see that the moon's shadow is better represented as a polygon. This more complicated shape is based NASA's Lunar Reconnaissance Orbiter's view of the mountains and valleys that form the moon's jagged edge. By combining moon's terrain, heights of land forms on Earth, and the angle of the sun, Wright is able to show the eclipse path with the greatest accuracy to date.
2017 Total Solar Eclipse Map and Shapefiles

2016.12.13

View the map of the United States that shows the path of the Moon's umbral shadow — the path of totality — during the total solar eclipse on August 21, 2017, as well as the obscuration (the fraction of the Sun's area covered by the Moon) in places outside the umbral path. Features include state boundaries, major highways, and 833 place names. At 18" × 9" (45 × 22.5 cm), the scale of the map is approximately 1:10,000,000. You can also download a zipped file bundle containing the shape files for this map area.

On Monday, August 21, 2017, the Moon will pass in front of the Sun, casting its shadow across all of North America. This will be the first total solar eclipse visible in the contiguous United States in 38 years. The Moon's shadow can be divided into areas called the umbra and the penumbra. Within the penumbra, the Sun is only partially blocked, and observers experience a partial eclipse. The much smaller umbra lies at the very center of the shadow cone, and anyone there sees the Moon entirely cover the Sun in a total solar eclipse. In the animation, the umbra is the small black oval. The red streak behind this oval is the path of totality. Anyone within this path will see a total eclipse when the umbra passes over them. The much larger shaded bullseye pattern represents the penumbra. Steps in the shading denote different percentages of Sun coverage (eclipse magnitude), at levels of 90%, 75%, 50% and 25%. The yellow and orange contours map the path of the penumbra. The outermost yellow contour is the edge of the penumbra path. Outside this limit, no part of the Sun is covered by the Moon. The numbers in the lower left corner give the latitude and longitude of the center of the umbra as it moves eastward, along with the altitude of the Sun above the horizon at that point. Also shown is the duration of totality: for anyone standing at the center point, this is how long the total solar eclipse will last. Note that the duration varies from just 2 minutes on the West Coast to 2 minutes 40 seconds east of the Mississippi River.

About Accuracy

You might think that calculating the circumstances of an eclipse would be, if not easy, then at least precise. If you do the math correctly, you’d expect to get exactly the same answers as everyone else. But the universe is more subtle than that. The Earth is neither smooth nor perfectly spherical, nor does it rotate at a perfectly constant, predictable speed. The Moon isn’t smooth, either, which means that the shadow it casts isn’t a simple circle. And our knowledge of the size of the Sun is uncertain by a factor of about 0.2%, enough to affect the duration of totality by several seconds. Everyone who performs these calculations will make certain choices to simplify the math or to precisely define an imperfectly known number. The choices often depend on the goals and the computing resources of the calculator, and as you'd expect, the results will differ slightly. You can get quite good results with a relatively simple approach, but it sometimes takes an enormous effort to get only slightly better answers. The following table lists some of the constants and data used for this animation.

Earth radius	6378.137 km
Earth flattening	1 / 298.257 (the WGS 84 ellipsoid)
Moon radius	1737.4 km (k = 0.2723993)
Sun radius	696,000 km (959.634 arcsec at 1 AU)
Ephemeris	DE 421
Earth orientation	earth_070425_370426_predict.bpc (ΔT corrected)
Delta UTC	68.184 seconds (TT – TAI + 36 leap seconds)

A number of sources explain Bessel’s method of solar eclipse calculation, including chapter 9 of Astronomy on the Personal Computer by Oliver Montenbruck and Thomas Pflager and the eclipses chapter of The Explanatory Supplement to the Astronomical Almanac. The method was adapted to the routines available in NAIF's SPICE software library. The value for the radius of the Moon is slightly larger than the one used by Fred Espenak and slightly smaller than the one used by the Astronomical Almanac. The Sun radius is the one used most often, but see figure 1 in M. Emilio et al., Measuring the Solar Radius from Space during the 2003 and 2006 Mercury Transits for a sense of the uncertainty in this number. Both the elevations of locations on the Earth and the irregular limb of the Moon were ignored. The resulting small errors mostly affect the totality duration calculation, but they tend to cancel out—elevations above sea level slightly lengthen totality, while valleys along the lunar limb slightly shorten it. The effect on the rendered images is negligible (smaller than a pixel). Another minor complication that's ignored here is the difference between the Moon's center of mass (the position reported in the ephemeris) and its center of figure (the center of the disk as seen from Earth). These two centers don't exactly coincide because the Moon's mass isn't distributed evenly, but the difference is quite small, about 0.5 kilometers.

Watching the Friendly Skies - Eclipse Safety Tutorial

During the August 21, 2017 total solar eclipse, the Moon's umbral shadow will fly across the United States, from Oregon to South Carolina, in a little over 90 minutes. The path of this shadow, the path of totality, is where observers will see the Moon completely cover the Sun for about two and a half minutes. People traveling to see totality, likely numbering in the millions for this eclipse, will rely on maps that show the predicted location of this path. The math used to make eclipse maps was worked out by Friedrich Wilhelm Bessel and William Chauvenet in the 19th century, long before computers and the precise astronomical data gathered during the Space Age. In keeping with their paper and pencil origins, traditional eclipse calculations pretend that all observers are at sea level and that the Moon is a smooth sphere centered on its center of mass. Reasonably accurate maps, including this one, are drawn based on those simplifying assumptions. Those who want greater accuracy are usually referred to elevation tables and plots of the lunar limb. This animation shows the umbra and its path in a new way. Elevations on the Earth's surface and the irregular lunar limb (the silhouette edge of the Moon's disk) are both fully accounted for, and they both have dramatic and surprising effects on the shape of the umbra and the location of the path. To read more about these effects, go here. The animation provides an overhead view of the umbra and runs at a rate of 30× real time — every minute of the eclipse takes two seconds in the animation. For an oblique view that emphasizes the terrain of the path, go here.

Earth radius	6378.137 km
Ellipsoid	WGS84
Geoid	EGM96
Moon radius	1737.4 km
Sun radius	696,000 km (959.645 arcsec at 1 AU)
Ephemeris	DE 421
Earth orientation	earth_070425_370426_predict.bpc (ΔT corrected)
Delta UTC	69.184 seconds (TT – TAI + 37 leap seconds)
ΔT	68.917 seconds

2017 Eclipse State Maps

2017.02.06

The path of totality passes through 14 states during the total solar eclipse on August 21, 2017. A map of each of these states, created for NASA's official eclipse 2017 website, is presented here. Except for Montana, each map is 8 inches wide (or high) at 300 DPI. The umbra is shown at 3-minute intervals, with times in the local time zone at the umbra center. The duration of totality is outlined in 30-second increments. Interstate highways are blue, other major roads are red, and secondary roads are gray. Some sources list only 12 states for this eclipse, but in fact the path of totality also grazes the southwestern borders of both Montana and Iowa. The Montana part of the path is in a roadless area at the southern end of the Beaverhead Mountains, a range that defines sections of both the Montana-Idaho border and the Continental Divide. The Iowa part of the path is west of Interstate 29 near Hamburg, south of 310 Street, and bounded on the west by the Missouri River. It includes the Lower Hamburg Bend Wildlife Management Area.

Eclipse Safety

How to View the Solar Eclipse with a Pinhole Projector

Watching the Friendly Skies - Eclipse Safety Tutorial

How to View the Solar Eclipse with a Pinhole Projector

Watching the Friendly Skies - Eclipse Safety Tutorial

How to View the Solar Eclipse with a Pinhole Projector

Watching the Friendly Skies - Eclipse Safety Tutorial

How to View the Solar Eclipse with a Pinhole Projector

Watching the Friendly Skies - Eclipse Safety Tutorial

2017.06.21

Get ready to view the solar eclipse with these helpful safety tips. No one should ever look directly at the sun, even during an eclipse. Many options for indirect viewing are outlined in this video.
How to View the Solar Eclipse with a Pinhole Projector

2017.06.21

You don't need fancy glasses or equipment to watch one of the sky's most awesome shows: a solar eclipse. With just a few simple supplies, you can make a pinhole camera that lets you watch a solar eclipse safely and easily from anywhere. Before you get started, remember: You should never look at the sun directly without equipment that's specifically designed for looking at the sun. Even using binoculars or a telescope, you could severely damage your eyes or even go blind! Solar eclipses themselves are safe. But looking at anything as bright as the sun is NOT safe without proper protection. And no, sunglasses do NOT count. Stay safe and still enjoy the sun's stellar shows by creating your very own pinhole camera. It's easy!
How to Safely Watch a Total Solar Eclipse

2017.06.21

It is never safe to look directly at the sun's rays – even if the sun is partly obscured. When watching a partial eclipse you must wear eclipse glasses at all times if you want to face the sun, or use an alternate indirect method. This also applies during a total eclipse up until the time when the sun is completely and totally blocked. During the short time when the moon completely obscures the sun – known as the period of totality – it is safe to look directly at the star, but it's crucial that you know when to take off and put back on your glasses. First and foremost: Check for local information on timing of when the total eclipse will begin and end. NASA's page of eclipse times is a good place to start. Second: The sun also provides important clues for when totality is about to start and end.
Get Ready for the 2017 Solar Eclipse

2017.06.21

On Monday, August 21, 2017, our nation will be treated to a total eclipse of the sun.
The eclipse will be visible -- weather permitting -- across all of North America. The whole continent will experience a partial eclipse lasting two to three hours. Halfway through the event, anyone within a 60 to 70 mile-wide path from Oregon to South Carolina will experience a total eclipse. During those brief moments when the moon completely blocks the sun’s bright face for 2 + minutes, day will turn into night, making visible the otherwise hidden solar corona, the sun’s outer atmosphere. Bright stars and planets will become visible as well. This is truly one of nature’s most awesome sights.
The eclipse provides a unique opportunity to study the sun, Earth, moon and their interaction because of the eclipse’s long path over land coast to coast. Scientists will be able to take ground-based and airborne observations over a period of an hour and a half to complement the wealth of data provided by NASA assets.
Learn more at https://eclipse2017.nasa.gov/safety Find more videos about the solar ecilpse at https://svs.gsfc.nasa.gov/Gallery/suneclipse2017.html
Solar Eclipse Safety Images

2017.07.25

People watch a partial eclipse in Belfast, Northern Ireland, on March 20, 2015. Credit: Robin Cordiner

Eclipse Science

A Total Solar Eclipse Revealed Solar Storms 100 Years Before Satellites

A Total Solar Eclipse Revealed Solar Storms 100 Years Before Satellites

A Total Solar Eclipse Revealed Solar Storms 100 Years Before Satellites

A Total Solar Eclipse Revealed Solar Storms 100 Years Before Satellites

A New View of August's Total Solar Eclipse

2017.07.20

During the August 2017 total solar eclipse, scientists will use the Earth Polychromatic Imaging Camera (EPIC) on the Deep Space Climate Observatory (DSCOVR) satellite, along with measurements taken from within the moon's shadow on the ground, to test a new model of Earth's energy budget.
NASA Jets Chase The Total Solar Eclipse

2017.07.25

For most viewers, the Aug. 21, 2017, total solar eclipse will last less than two and half minutes. But for one team of NASA-funded scientists, the eclipse will last over seven minutes. Their secret? Following the shadow of the Moon in two retrofitted WB-57F jet planes.
Amir Caspi of the Southwest Research Institute in Boulder, Colorado, and his team will use two of NASA’s WB-57F research jets to chase the darkness across America on Aug. 21. Taking observations from twin telescopes mounted on the noses of the planes, Caspi will capture the clearest images of the Sun’s outer atmosphere — the corona — to date and the first-ever thermal images of Mercury, revealing how temperature varies across the planet’s surface.
Earth's Energy Budget

2017.07.20

Earth's energy budget is a metaphor for the delicate equilibrium between energy received from The Sun versus energy radiated back out in to space. Research into precise details of Earth's energy budget is vital for understanding how the planet's climate may be changing, as well as variabilities in solar energy output. Missions like NASA's TSIS will help scientists keep a close watch.
2 Minutes, 6 Hands, 1 Chance

2017.08.07

A team of three scientists have two minutes to complete an experiment during the 2017 total solar eclipse.
A Total Solar Eclipse Revealed Solar Storms 100 Years Before Satellites

2017.08.17

Eclipses set the stage for historic science. NASA is taking advantage of the Aug. 21, 2017 eclipse by funding 11 ground-based scientific studies. As our scientists prepare their experiments for next week, we're looking back to an historic 1860 total solar eclipse, which many think gave humanity our first glimpse of solar storms — called coronal mass ejections — 100 years before scientists first understood what they were.
Scientists observed these eruptions in the 1970s during the beginning of the modern satellite era, when satellites in space were able to capture thousands of images of solar activity that had never been seen before. But in hindsight, scientists realized their satellite images might not be the first record of these solar storms. Hand-drawn records of an 1860 total solar eclipse bore surprising resemblance to these groundbreaking satellite images.
Eclipse archive imagery from: http://mlso.hao.ucar.edu/hao-eclipse-archive.php

All August 21, 2017 Eclipse Visualizations

August 21, 2017 Total Solar Eclipse Path for Spherical Displays

August 21, 2017 Total Solar Eclipse Path for Spherical Displays

August 21, 2017 Total Solar Eclipse Path for Spherical Displays

August 21, 2017 Total Solar Eclipse Path for Spherical Displays

2017.02.15

2017 Eclipse Path

On Monday, August 21, 2017, the Moon will pass in front of the Sun, casting its shadow across all of North America. This will be the first total solar eclipse visible in the contiguous United States in 38 years. The Moon's shadow can be divided into areas called the umbra and the penumbra. Within the penumbra, the Sun is only partially blocked, and observers experience a partial eclipse. The much smaller umbra lies at the very center of the shadow cone, and anyone there sees the Moon entirely cover the Sun in a total solar eclipse. In the animation, the umbra is the small black oval. The red streak behind this oval is the path of totality. Anyone within this path will see a total eclipse when the umbra passes over them. The much larger shaded bullseye pattern represents the penumbra. Steps in the shading denote different percentages of Sun coverage, at levels of 90%, 75%, 50% and 25%. The yellow and orange contours map the path of the penumbra. The outermost yellow contour is the edge of the penumbra path. Outside this limit, no part of the Sun is covered by the Moon. The numbers in the lower left corner give the latitude and longitude of the center of the umbra as it moves eastward, along with the altitude of the Sun above the horizon at that point. Also shown is the duration of totality: for anyone standing at the center point, this is how long the total solar eclipse will last. Note that the duration varies from just 2 minutes on the West Coast to 2 minutes 40 seconds east of the Mississippi River.

About Accuracy

Earth radius	6378.137 km
Earth flattening	1 / 298.257 (the WGS 84 ellipsoid)
Moon radius	1737.4 km (k = 0.2723993)
Sun radius	696,000 km (959.634 arcsec at 1 AU)
Ephemeris	DE 421
Earth orientation	earth_070425_370426_predict.bpc (ΔT corrected)
Delta UTC	68.184 seconds (TT – TAI + 36 leap seconds)

Shadow Cones

2015.09.09

A solar eclipse occurs when the Moon's shadow falls on the Earth. The shadow comprises two concentric cones called the umbra and the penumbra. Within the smaller, central umbra, the Sun is completely blocked by the Moon, and anyone inside the umbra sees a total eclipse. Within the larger penumbra, the Sun is only partially blocked. In this animation, the umbra and penumbra cones are viewed through a telescopic lens on a virtual camera located far behind the Moon. Long focal lengths like the one used here appear to compress the distance between near and far objects. Despite appearances, the geometry of the scene is correct. The Earth is roughly 112 lunar diameters beyond the Moon, and the angle at the apex of the umbral cone is only about half a degree. From this point of view directly behind the Moon, the edges of the shadow cones look circular. The edge of the penumbra is outlined in yellow. It passes over all of North and Central America and the Amazon basin, as well as Greenland and the North Pole. Everyone there will see at least a partial eclipse. The path of the umbra (the small black dot) crosses the United States from Oregon to South Carolina.
Moon's Orbit

2015.09.09

Solar eclipses can only occur at New Moon, when the Moon is between the Earth and the Sun. But not every New Moon produces an eclipse. The Moon's orbit is slightly tilted, and as seen in this animation, the tilt causes the Moon's shadow to miss the Earth during most New Moons—about five out of six, in fact. As the Earth-Moon system orbits the Sun throughout the year, the Moon's orbital tilt changes direction relative to the Sun. Sometimes the up side of the orbit is facing the Sun, and sometimes the down side. Twice a year, for about a month, what's facing the Sun is the line dividing the up and down sides. This is the line of nodes, the intersection of the Earth-Moon plane and the ecliptic or Earth-Sun plane. A solar eclipse can only occur at a New Moon that falls within one of these month-long eclipse seasons. That's when the Moon is close enough to the ecliptic to actually come between the Earth and the Sun. In this animation, the olive-colored square represents the ecliptic plane, while the light blue circle shows the plane of the Moon's orbit. The darker half of the lunar orbit plane is below (south of) the ecliptic, and the dividing line between light and dark is the line of nodes. The radial grid on the lunar orbit plane is stationary relative to the stars. It appears to rotate because our point of view is fixed to the Earth-Sun line; we're following the Earth as it orbits the Sun. At first glance, the line of nodes appears to be tracking with the grid, but in reality it's slowly turning westward (clockwise), completing a full revolution in 18.6 years. Unlike most illustrations of this kind, the Earth and the Moon are to scale. The Sun is off-screen to the left, about 400 times farther than the Earth-Moon distance and roughly twice as big as the Moon's orbit.
Earth, Moon and Sun

2015.10.20

The Moon moves right to left in its orbit around the Earth, while the shadow it casts hits the Earth during the August 21, 2017 total solar eclipse.
Insolation during the 2017 Eclipse

2016.05.23

On an ordinary day, the insolation — the amount of sunlight hitting a given spot on the Earth — is proportional to the sine of the Sun's altitude. When the Sun is 30° above the horizon, the sunlight energy per square meter is half of what it is when the Sun is directly overhead. This relationship is the reason that the tropics are hot and the poles are cold. Combined with day length, it's also the reason for the difference in temperature between the seasons at temperate latitudes. As this animation shows, the Moon's shadow dramatically, if temporarily, affects insolation in the continental United States during the total solar eclipse of August 21, 2017. The effect is readily apparent to observers in the path of totality. As the umbra passes overhead, the temperature drops by several degrees. The cooled column of air within the shadow cone can even influence cloud formation and the speed and direction of the wind. The insolation map in the animation combines solar altitude with obscuration, the fraction of the Sun's area blocked by the Moon during the eclipse. It ignores a number of other factors, including atmospheric scattering, refration, and cloud cover, that also play a role in the amount of sunlight that reaches the ground.
2017 Solar Eclipse from L1

2016.05.23

A number of satellites will be watching the August 21, 2017 total solar eclipse from space. One of them, the Deep Space Climate Observatory (DSCOVR) will see the eclipse from its orbit around L1, the Lagrange point located about 1.5 million kilometers from Earth along the Earth-Sun line. From this vantage point, DSCOVR's EPIC camera continuously images the full sunlit disk of the Earth. This animation simulates the view that EPIC will have of the 2017 eclipse. The shadow size and opacity are based on the eclipse obscuration, the fraction of the Sun's disk covered by the Moon. The bright spot near the equator is the reflection of the Sun on the water. The red streak shows the path of totality, the locations on the Earth where observers will see the Sun completely covered by the Moon. EPIC will see both the Moon's shadow and the Sun's reflection because DSCOVR's orbit takes it several degrees off both the Sun-Earth line and the Sun-Moon line. For the same reason, the Moon will not be in the frame. The animation places the virtual camera in a plausible position for DSCOVR. The actual position of the spacecraft at the time of the eclipse will be affected by adjustments to its orbit that may be made in the coming months. EPIC has already captured the total solar eclipse of March, 2016.

Earth radius	6378.137 km
Ellipsoid	WGS84
Geoid	EGM96
Moon radius	1737.4 km
Sun radius	696,000 km (959.645 arcsec at 1 AU)
Ephemeris	DE 421
Earth orientation	earth_070425_370426_predict.bpc (ΔT corrected)
Delta UTC	69.184 seconds (TT – TAI + 37 leap seconds)
ΔT	68.917 seconds

Are You Ready for the Eclipse? (Live Interviews on Aug. 16, 2017)

During the August 21, 2017 total solar eclipse, the Moon's umbral shadow will fly across the United States, from Oregon to South Carolina, in a little over 90 minutes. The path of this shadow, the path of totality, is where observers will see the Moon completely cover the Sun for about two and a half minutes. People traveling to see totality, likely numbering in the millions for this eclipse, will rely on maps that show the predicted location of this path. The math used to make eclipse maps was worked out by Friedrich Wilhelm Bessel and William Chauvenet in the 19th century, long before computers and the precise astronomical data gathered during the Space Age. In keeping with their paper and pencil origins, traditional eclipse calculations pretend that all observers are at sea level and that the Moon is a smooth sphere centered on its center of mass. Reasonably accurate maps, including this one, are drawn based on those simplifying assumptions. Those who want greater accuracy are usually referred to elevation tables and plots of the lunar limb. This animation shows the umbra and its path in a new way. Elevations on the Earth's surface and the irregular lunar limb (the silhouette edge of the Moon's disk) are both fully accounted for, and they both have dramatic and surprising effects on the shape of the umbra and the location of the path. To read more about these effects, go here. The animation runs at a rate of 30× real time — every minute of the eclipse takes two seconds in the animation. The oblique view emphasizes the terrain of the umbral path. For an overhead view, go here.

Earth radius	6378.137 km
Ellipsoid	WGS84
Geoid	EGM96
Moon radius	1737.4 km
Sun radius	696,000 km (959.645 arcsec at 1 AU)
Ephemeris	DE 421
Earth orientation	earth_070425_370426_predict.bpc (ΔT corrected)
Delta UTC	69.184 seconds (TT – TAI + 37 leap seconds)
ΔT	68.917 seconds

Umbra Shapes

2016.12.13

For centuries, eclipse maps have depicted the shape of the Moon's umbra on the ground as a smooth ellipse. But as this visualization shows — in a way never seen before — the shape is dramatically altered by both the rugged lunar terrain and the elevations of observers on the Earth. The lunar umbra is the part of the Moon's shadow where the entire Sun is blocked by the Moon. In space, it's a cone extending some 400,000 kilometers behind the Moon. When the small end of this cone hits the Earth, we experience a total solar eclipse. The umbra shape discussed here is the intersection of the umbra cone with the surface of the Earth. On an eclipse map, this tells you where to stand in order to experience totality. 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 (or first) spot on the limb that lets sunlight through. This is the location of the diamond part of the diamond ring effect visible in the seconds just before or just after totality. An observer standing at the cusp where two edges meet will be treated to a double diamond ring. As these edges pass over mountain ranges (for the 2017 eclipse, the Cascades, Rockies, and Appalachians), they are scalloped by the peaks and valleys of the landscape. The higher elevations in the western states in 2017 also shift the umbra toward the southeast (in the direction of the Sun's azimuth) by as much as 3 kilometers. In the animation, the red ellipse is the shape that results from assuming that the Moon and the Earth are both smooth. This is the shape most commonly seen on eclipse maps. The white shape shows the effect of the mountains and valleys along the silhouette edge of the Moon (the lunar limb). The dark gray shape adds the effect of elevations on the Earth's surface.
2017 Total Solar Eclipse Map and Shapefiles

2016.12.13

View the map of the United States that shows the path of the Moon's umbral shadow — the path of totality — during the total solar eclipse on August 21, 2017, as well as the obscuration (the fraction of the Sun's area covered by the Moon) in places outside the umbral path. Features include state boundaries, major highways, and 833 place names. At 18" × 9" (45 × 22.5 cm), the scale of the map is approximately 1:10,000,000. You can also download a zipped file bundle containing the shape files for this map area.
Narrated Video - Tracing the 2017 Solar Eclipse

2016.12.14

When depicting an eclipse path, data visualizers have usually chosen to represent the moon's shadow as an oval. By bringing in a variety of NASA data sets, visualizer Ernie Wright has created a new and more accurate representation of the eclipse. For the first time, we are able to see that the moon's shadow is better represented as a polygon. This more complicated shape is based NASA's Lunar Reconnaissance Orbiter's view of the mountains and valleys that form the moon's jagged edge. By combining moon's terrain, heights of land forms on Earth, and the angle of the sun, Wright is able to show the eclipse path with the greatest accuracy to date.
2017 Eclipse State Maps

2017.02.06

The path of totality passes through 14 states during the total solar eclipse on August 21, 2017. A map of each of these states, created for NASA's official eclipse 2017 website, is presented here. Except for Montana, each map is 8 inches wide (or high) at 300 DPI. The umbra is shown at 3-minute intervals, with times in the local time zone at the umbra center. The duration of totality is outlined in 30-second increments. Interstate highways are blue, other major roads are red, and secondary roads are gray. Some sources list only 12 states for this eclipse, but in fact the path of totality also grazes the southwestern borders of both Montana and Iowa. The Montana part of the path is in a roadless area at the southern end of the Beaverhead Mountains, a range that defines sections of both the Montana-Idaho border and the Continental Divide. The Iowa part of the path is west of Interstate 29 near Hamburg, south of 310 Street, and bounded on the west by the Missouri River. It includes the Lower Hamburg Bend Wildlife Management Area.
August 21, 2017 Total Solar Eclipse Path for Spherical Displays

2017.02.15

On Monday, August 21, 2017, the Moon will pass in front of the Sun, casting its shadow across all of North America. This will be the first total solar eclipse visible in the contiguous United States in 38 years. The Moon's shadow can be divided into areas called the umbra and the penumbra. Within the penumbra, the Sun is only partially blocked, and observers experience a partial eclipse. The much smaller umbra lies at the very center of the shadow cone, and anyone there sees the Moon entirely cover the Sun in a total solar eclipse. In the animation, the umbra is the small black oval. The red streak behind this oval is the path of totality. Anyone within this path will see a total eclipse when the umbra passes over them. The much larger shaded bullseye pattern represents the penumbra. Steps in the shading denote different percentages of Sun coverage (eclipse magnitude), at levels of 90%, 75%, 50% and 25%. The yellow and orange contours map the path of the penumbra. The outermost yellow contour is the edge of the penumbra path. Outside this limit, no part of the Sun is covered by the Moon. The animation covers the four hours from 16:25:40 UTC to 20:25:30 UTC with time steps of 10 seconds between frames.

Live Shots

B-roll packages and interview clips from scientists in Spanish and English

Rare Total Solar Eclipse Is Only Two Months Away Live Shots 6.21.17

Are You Ready for the Eclipse? (Live Interviews on Aug. 16, 2017)

Rare Total Solar Eclipse Is Only Two Months Away Live Shots 6.21.17

Are You Ready for the Eclipse? (Live Interviews on Aug. 16, 2017)

Rare Total Solar Eclipse Is Only Two Months Away Live Shots 6.21.17

Are You Ready for the Eclipse? (Live Interviews on Aug. 16, 2017)

Rare Total Solar Eclipse Is Only Two Months Away Live Shots 6.21.17

Are You Ready for the Eclipse? (Live Interviews on Aug. 16, 2017)

2017.08.06

Are you ready for the historic solar eclipse that’s just days away? Do you have what you need to see it safely? You can see the eclipse no matter where you are in North America on Aug. 21!
August 21 will be a day for the history books. No matter where you are in North America, you’ll get to experience the first coast-to-coast solar eclipse in nearly a century! The dark shadow of the moon will sweep from Oregon to South Carolina, putting 14 states in the path of totality and providing a spectacular view of a partial eclipse across all 50 states.
Eclipses are an incredible experience, but it’s important to view them safely. Join NASA scientists on Wednesday, August 16, from 6:00 a.m. – 12:30 p.m. ET and again from 3:00 p.m. – 8:00 p.m. ET to show your viewers what they need to safely see the eclipse whether they’re inside the path of totality or not.
You should never look directly at the sun! The only safe way to look directly at the sun or partially eclipsed sun is through special-purpose solar filters, such as “eclipse glasses” or hand-held solar viewers. An eclipse is a striking phenomenon you won't want to miss, but you must carefully follow safety procedures.
Solar eclipses happen somewhere in the world about every 18 months, but much of the time it happens over the ocean. To have an eclipse travel across so much land where millions of people live is incredibly rare, and makes for a unique opportunity for so many to witness one of nature’s most impressive shows. It’s also a great opportunity for scientists to see the sun’s faint outer atmosphere and evaluate how Earth responds to the sudden darkening.
Take this opportunity to step outside and safely watch one of nature’s best shows!
*** To book a window *** Contact Michelle Handleman michelle.z.handleman@nasa.gov / 301-286-0918
HD Satellite Digital Coordinates for G17-K20/Up: Galaxy 17, Ku-band Xp 20, Slot Upper | 91.0 ° W Longitude | DL 12109.0 MHz | Vertical Polarity | QPSK/DVB-S | FEC 3/4 | SR 13.235 Mbps | DR 18.2954 MHz | HD 720p | Format MPEG2 | Chroma Level 4:2:0 | Audio Embedded
Suggested Questions: 1. The anticipated solar eclipse is just days away! What will we experience next week? 2. We’ve been told never to look directly at the sun (even with sunglasses!). How can we enjoy this eclipse safely? 3. For those in the path of totality – when is it safe to finally take off our solar glasses? 4. We’re not in the path of totality – what interesting things should we lookout for? 5. Why are you excited for this eclipse? 6. Where can we learn more?
Extra Questions for Longer Interviews: 7. How did a picture of an eclipse in 1919 prove Einstein’s theory of relativity? 8. Eclipses are actually a special type of transit. How are transits helping scientists search for life on other planets? 9. Why does an eclipse only last for a few minutes? 10. What happens to Earth during the eclipse? 11. If you were looking back at Earth during the eclipse what would you see? 12. How has our precise mapping of the moon helped us predict the path of eclipses? 13. How long and where was the longest ever recorded eclipse?
Location: NASA’s Goddard Space Flight Center/Greenbelt, Maryland
Interviews With: Dr. Michelle Thaller / NASA Scientist Dr. Alex Young / NASA Scientist Dr. Jim Garvin / NASA Scientist Dr. Nicholeen Viall / NASA Scientist Dr. Eric Christian / NASA Scientist Dr. Yari Collado-Vega / NASA Scientist [Spanish speaker] Dr. Geronimo Villanueva / NASA Scientist [Spanish speaker]

https://eclipse2017.nasa.gov/ @NASASun How to photograph an eclipse. Planning to take photos of #Eclipse2017? Check out our tips for capturing the best images:#eclipse
Rare Total Solar Eclipse Is Only Two Months Away Live Shots 6.21.17

2017.06.13

The Countdown is on for Rare Solar Eclipse Visible Across all of North America For the First Time in Nearly 100 Years, Millions of Americans Coast-to-Coast Will see an Eclipse Chat with NASA to find out how you can catch this spectacular event
On August 21, 2017, daylight will fade to the level of a moonlit night as millions of Americans experience one of nature’s most awe-inspiring shows – a total solar eclipse. For the first time since 1918, the dark shadow of the moon will sweep coast-to-coast across the United States, putting 14 states in the path of totality and providing a spectacular view of a partial eclipse across all 50 states.
NASA scientists are available Wednesday, June 21, from 6:00 a.m. – 12:00 p.m. ET to show your viewers the path of the eclipse, what they need to see it safely and talk about the unprecedented science that will be gathered from one of the most anticipated and widely observed celestial events in history. We’ll also give your viewers a sneak peek of a press conference about the eclipse NASA is having later that day.
A solar eclipse happens when a rare alignment of the sun and moon casts a shadow on Earth. NASA knows the shape of the moon better than any other planetary body, and this data allows us to accurately predict the shape of the shadow as it falls on the face of Earth. While everyone in the U.S. will see the eclipse if their local skies are clear, people standing in the path of totality – completely in the moon’s shadow – will see stars and planets become visible in what is normally a sunlit sky.
Eclipses provide an unprecedented opportunity for us to see the sun’s faint outer atmosphere in a way that cannot be replicated by current human-made instruments. Scientists believe this region of the sun is the main driver for the sun’s constant outpouring of radiation, known as the solar wind, as well as powerful bursts of solar material that can be harmful to our satellites, orbiting astronauts and power grids on the ground.
HD Satellite Coordinates for G17-K18/LO: Galaxy 17 Ku-band Xp 18 Slot Lower | 91.0 ° W Longitude | DL 12051.0 MHz | Vertical Polarity | QPSK/DVB-S | FEC 3/4 | SR 13.235 Mbps | DR 18.2954 MHz | HD 720p | Format MPEG2 | Chroma Level 4:2:0 | Audio Embedded
**To book a window contact** / Michelle Handleman / michelle.z.handleman@nasa.gov / 301-286-0918
Suggested Questions: 1. This is the first time in nearly 100 years that the United States will have the opportunity to see a total solar eclipse coast-to-coast! What will happen on August 21? 2. This eclipse will be the most widely observed and shared celestial event in U.S. history. Why are scientists excited for this eclipse? 3. Eclipses allow scientists to see the sun’s faint outer atmosphere, which is actually hotter than its surface. What can you tell us about NASA’s upcoming mission that will touch the sun? 4. How does NASA’s study of our sun help us explore the solar system? 5. How does NASA’s mapping of the moon give us the accurate path of totality? 6. Where can we learn more?
Live Shot Details:
Location: NASA’s Goddard Space Flight Center/Greenbelt, Maryland
Scientists: Dr. Alex Young / NASA Scientist Dr. Nicholeen Viall / NASA Scientist Dr. Noah Petro / NASA Scientist Dr. Geronimo Villanueva [in Spanish] / NASA Scientist
To learn more visit: Eclipse Across America On Twitter @NASASun
2017 Solar Eclipse Video File

2017.06.21

Slug: NASA Gears up for August 21, 2017, Eclipse Across America
Description: On Monday, Aug. 21, 2017, a total eclipse will cross the entire country, coast-to-coast, for the first time since 1918. Weather permitting, the entire continent will have the opportunity to view an eclipse as the moon passes in front of the sun, casting a shadow on Earth’s surface. The total solar eclipse begins near Lincoln City, Oregon, at 10:15 a.m. PDT (1:15 p.m. EDT). Totality ends at 2:48 p.m. EDT near Charleston, South Carolina. The total eclipse itself will take about one hour and 40 minutes to cross the country. Observers outside this path will still see a partial solar eclipse where the moon covers part of the sun's disk. All of North America will have a view of at least a partial eclipse.
Super(s): NASA Center Contact: Karen Fox, karen.c.fox@nasa.gov, 301-286-6284 HQ Contact: Dwayne Brown, dwayne.c.brown@nasa.gov, 202-358-1726 For more information: https://eclipse2017.nasa.gov/
2017 Spring Equinox Live Shots

2017.03.15

March 20 Equinox Marks the Start of Spring in the Northern Hemisphere
Dance of the Solar System is the First Solar Event of 2017
Stay Tuned for the Big Event of 2017, the August Solar Eclipse!
It may not feel like it this week in parts of the country, but spring begins in just a few days. March 20 kicks off the first day of astronomical spring in the Northern Hemisphere. On March 20, the day of the spring Equinox, the sun will pass directly over the Earth’s equator, giving the entire planet equal hours of day and night. This is the seasonal marker in Earth’s orbit around the sun when daylight hours begin to get longer than night.
This dance of the solar system is just one celestial event we’ll see this year. On August 21 all 50 states in the U.S. will be in prime position to see a partial or even a total solar eclipse, which happens when the moon is in perfect position to blot out the sun’s bright disk. The last time the U.S. saw a coast-to-coast solar eclipse was in 1918! The path of totality runs from Oregon to South Carolina.
NASA will lead an unprecedented science initiative during the eclipse that will draw on the collaboration of the public to help collect images, data and even temperature readings from across the nation during the hour-and-a-half it takes to cross the continent.
NASA scientists are available on Monday, March 20 from 6:00 a.m. – 11:30 a.m. EDT to help your viewers ring in the new season and talk about the big solar event this August.
***To book a window contact*** Michelle Handleman / michelle.z.handleman@nasa.gov/ 301-286-0918
HD Satellite Coordinates for G17-K18Upper: Galaxy 17 Ku-band Xp 18 Slot Upper| 91.0 ° W Longitude | DL 12069.0 MHz | Vertical Polarity | QPSK/DVB-S | FEC 3/4 | SR 13.235 Mbps | DR 18.2954 MHz | HD 720p | Format MPEG2 | Chroma Level 4:2:0 | Audio Embedded
Suggested Questions:
1. What is an equinox?
2. There is an exciting event happening this year: a total solar eclipse! When is this happening?
3. NASA will be doing some pretty cool science during the eclipse. How is NASA using the eclipse to study the sun and Earth?
4. How do eclipses help us find planets orbiting other stars?
5. Where can we learn more?
Live Shot Details:
Location: NASA’s Goddard Space Flight Center/Greenbelt, Maryland
Scientists:
Dr. Alex Young/ NASA Scientist
Dr. Yari Collado-Vega / NASA Scientist [Interviews in Spanish]
Dr. Nicholeen Viall / NASA Scientist
Video: NASA will roll all insert videos during live interviews. If needed, stations can roll a clean feed of all video at 5:45 a.m. EDT on March 20, at the above listed satellite.
2016 Total Solar Eclipse Live Shots

2016.03.03

NASA scientists discuss the March 8/9, 2016 total solar eclipse. A Moment in the Sun’s Atmosphere: NASA’s Science During the March 2016 Total Solar Eclipse Eye Safety During a Total Solar Eclipse More on Twitter @NASASunEarth Share your eclipse pictures

Observing The Sun

Space Weather Vocabulary

2013.02.26

We are all familiar with weather on Earth, but how much do you know about weather in space? Suitable for all ages, this introduction to space weather covers vocabulary like coronal mass ejection (CME), solar wind, and solar flare. It also outlines potential effects of solar storms on our planet.
This video is available in English and Spanish, both with English subtitles.
Todo el mundo está familiarizado con el clima de la Tierra pero, ¿cuánto sabes sobre meteorología espacial? Este video introductorio al clima espacial, apropiado para todas las edades y niveles, explica términos científicos como eyección de masa coronal, viento solar o erupción solar.También provee una descripción general sobre los efectos potenciales que tienen las tormentas solares en nuestro planeta.
El vídeo está disponible en español e inglés, ambas versiones con subtítulos en inglés.
SDO 4k Slow-rotation Sun Resource Page

2017.06.02

SDO, the Solar Dynamics Observatory, images the entire sun at 4096x4096 resolution in multiple wavelengths every 12 seconds. The selection below represents some of the best options for full-disk slow rotation. The 4k content is available for download as frame sequences, and, in some cases, as ProRes video. These files are large and will take a long time to download.
SDO Anniversary Series

2017.06.02

The sun is always changing and NASA's Solar Dynamics Observatory is always watching. Launched on Feb. 11, 2010, SDO keeps a 24-hour eye on the entire disk of the sun, with a prime view of the graceful dance of solar material coursing through the sun's atmosphere, the corona.

Press Conference Materials

June 21, 2017 Solar Eclipse Press Conference

2017.06.21
AGU 2017 Eclipse Press Conference

2016.12.14

Graphic depicting the geometry of a total solar eclipse.
Credit: NASA

Past Eclipses Seen from Earth - Solar

March 2016 Eclipse Path

2016.02.12

The animated shadow path of the March 9, 2016 total solar eclipse, showing the umbra (black oval), penumbra (concentric shaded ovals), and path of totality (red) through Indonesia and the western Pacific.
March 2016 Eclipse Shadow Cones

2016.02.12

The umbral and penumbral shadow cones travel across the surface of the Earth during the March 9, 2016 total solar eclipse.
March 2016 Eclipse: Earth, Moon and Sun

2016.02.12

The Moon moves right to left in its orbit around the Earth. The shadow it casts hits the Earth during the March 9, 2016 total solar eclipse.
March 2016 Eclipse and the Moon's Orbit

2016.02.12

The Moon orbits the Earth in the months prior to the March 9, 2016 (March 8 in the Americas) total solar eclipse. Viewed from above, the Moon's shadow appears to cross the Earth every month, but a side view reveals the five-degree tilt of the Moon's orbit. Its shadow only hits the Earth when the line of nodes, the fulcrum of its orbital tilt, is pointed toward the Sun.
The Total Solar Eclipse of 20 March 2015

2015.03.13

On March 20, 2015, the shadow of the Moon crosses the surface of the Earth, creating a total solar eclipse. The eclipse occurs on the date of the March equinox, the start of spring in the northern hemisphere. From well beyond the Moon's far side, the shadow appears circular. The central black dot is the umbra, where the Sun is completely covered by the Moon. The fainter, much larger shadow is the penumbra, where the Sun is only partially obscured. Viewed from overhead, the umbra is quite elongated. It hits the Earth at a glancing angle, beginning at a point south of Greenland and departing very near the north pole. The Faroe Islands and the Svalbard archipeligo are in the path of the umbra, but the umbra just misses Iceland, and it crosses no other populated land. The penumbra covers all of Europe and extends to north Africa and across most of Russia. Everyone in those places will see a partial eclipse. Both astronauts and robotic probes have witnessed solar eclipses from space. For the annular eclipse in May of 2012, Lunar Reconnaissance Orbiter turned its narrow-angle camera away from the Moon and toward Earth, capturing four still images of the Moon's shadow as it traveled from Japan to the Aleutian Islands and the west coast of the United States.
LRO Images the May 2012 Solar Eclipse

2012.05.25

On May 20, 2012, Lunar Reconnaissance Orbiter turned away from the Moon so that its camera (LROC) could point at the Earth. LRO periodically uses the Earth as a target for calibrating the cameras, but in this case, it was imaging the shadow of the Moon during an annular solar eclipse. The LROC narrow-angle camera (NAC) captured four images of the shadow on two successive lunar orbits. This isn't as easy as pressing the shutter button. Each of the twin NACs comprises a single scanline of 5064 pixels. Ordinarily, the camera is pointed straight down at the Moon, and the orbital motion of the spacecraft sweeps the scanline over the lunar surface to build up an image. (This sweeping business is the reason such single-scanline cameras are often called pushbroom sensors.) To take a photo of the Earth, LRO must be continuously rotated, or slewed, to sweep the scanline across the disk of our home planet. After the first photo in each orbit, LRO's slew was reversed, sweeping the scanline in the opposite direction. Because the Moon's orbit is elliptical, its distance from Earth and its apparent size in the sky can vary by about 14%. An annular eclipse is a solar eclipse that occurs when the Moon is at the far end of this range and isn't quite big enough to cover the Sun, leaving a ring, or annulus, of sunlight around the edge of the Moon. This is why there's no central black umbra in the LROC images.
Total Solar Eclipse - August 1, 2008

2008.05.13

On Friday, 2008 August 01, a total eclipse of the Sun will be visible from within a narrow coridor that traverses half the Earth. This animation shows the Moon passing between the Earth and Sun.

Past Eclipses Seen from Earth - Lunar