Recognizing Giant Leaps: Google Lunar XPRIZE Establishes Milestone Prizes (Op-Ed)

Back in 2007, building upon the successes of the Ansari XPRIZE for suborbital spaceflight and the Northrop Grumman Lunar Lander Challenge, XPRIZE and Google launched the $30 million Google Lunar XPRIZE, the largest incentivized competition to date. The concept was easy to explain: land on the moon, move 500 meters and send back video, images and data. The prize requirements were conceived to demonstrate the minimum useful capability a spacecraft would need for future uses in space exploration and scientific research.

Thirty teams signed up for this audacious challenge by the close of registration in 2010 — three times as many as the initial concept study had suggested. Going back to the moon had clearly struck a chord!

This week, XPRIZE and Google announced a series of Milestone Prizes available to competing teams. The reason for introducing these prizes deserves a little background.

Over the past decade, XPRIZE has successfully launched and awarded a number of competitions, learning a great deal about what makes for optimum prize design. We've learned that success is more likely if we continue to keep our eye on the entire ecosystem surrounding a prize, and when we address any significant challenges to that ecosystem that may arise.

Given the large investment investment needed to send a robot to the moon, two elements of the Google Lunar XPRIZE ecosystem are critical: potential customers for the technology developed by teams, and investors to help create the businesses to leverage those markets. In both of these areas, much has changed since the Google Lunar XPRIZE was launched. The global economic downturn has reduced an already small pool of investors who are willing to take risks on pioneering new markets. This same downturn has also stagnated or reduced the budgets that governments — usually an early future customer — are willing to spend in space exploration (of note, NASA has changed its focus from going back to the moon to exploring asteroids ).

Two years ago, XPRIZE began a dialogue with teams to better understand the challenges that they were facing and to determine what steps we might take to better nurture and support this prize ecosystem. As a result, we determined that we needed to find a way to recognize and support the teams that were making substantial technical progress toward the requirements of the competition.

Hence the newly announced Milestone Prizes.

Within the next year, there are certain developmental milestones for flight-ready hardware that teams must pass in order to meet the mission requirements and be ready to launch by the deadline of Dec. 31, 2015.

Recognizing and rewarding these milestones will not only help the competing teams by allowing them to access financing at a critical point in their mission timeline, but it will also raise public excitement and support for the teams.

The Milestone Prizes are for demonstrating (via actual testing and analysis) robust hardware and software to combat key technical risks in the areas of imaging, mobility and lander systems — all three being necessary to achieve a successful Google Lunar XPRIZE mission. Teams will submit their proposals to our judging panel, which will select up to four proposals to monitor in each of the imaging and mobility subsystems, and three proposals for the lander system, for a total of 11 proposals. A team may have proposals selected in more than one area.

Provided the team successfully accomplishes the tasks described in their selected proposal in the timeframe agreed, they will win a Milestone Prize. The amounts are $250,000 for the Imaging Subsystem Milestone Prize (for up to 4 teams), $500,000 for the Mobility Subsystem Milestone Prize (for up to 4 teams), and $1 million for the Lander System Milestone Prize (for up to 3 teams), for a total purse of $6 million. The Milestone Prizes can be won through the end of September 2014.

With the introduction of these prizes, 2014 is looking to be a very exciting year for the Google Lunar XPRIZE with critical hardware and software testing and many great opportunities to recognize our teams and their significant achievements. While we cannot fix the global economic downturn, we can at least highlight the ways in which our teams are bringing us closer to a new era of private lunar exploration, taking us back to the moon, for good.

Source of Article: Space.com

Bizarre Asteroid with Six Tails Spotted by Hubble Telescope (Photos)

Astronomers have spotted a never-before-seen phenomenon in our solar system's asteroid belt: a space rock with six tails, spewing dust from its nucleus like spouts of water radiating from a lawn sprinkler.

Scientists using the Pan-STARRS 1 telescope at the summit of Maui's Haleakala volcano in Hawaii first detected the six-tailed asteroid in August. They dubbed it P/2013 P5 and noted that it looked fuzzier than typical asteroids, which usually appear as tiny points of light. More detailed observations with the powerful Hubble Space Telescope in September revealed a clearer picture of asteroid, showing it had six comet-like tails.

"We were literally dumbfounded when we saw it," researcher David Jewitt of the University of California at Los Angeles said in a statement from NASA. "Even more amazing, its tail structures change dramatically in just 13 days as it belches out dust. That also caught us by surprise. It's hard to believe we're looking at an asteroid."

In the time between Hubble's first observation on Sept. 10 and its second peek at the asteroid on Sept. 23, the tails appeared to have completely swung around. Jewitt said he and his colleagues were "completely knocked out" by this finding.

The tails seem to have formed in bursts and not all at once, which is why the researchers don't think they formed as the result of an impact with another asteroid.

Rather, P/2013 P5 could have sprouted dust tails after it started spinning out of control. The researchers suspect radiation pressure caused the asteroid to start rotating faster and faster until its weak gravity no longer could hold it together, sending the surface material of the space rock flying off at several points in the asteroid's recent history.

The researchers even pinpointed when they think these recent dust-ejection events may have occurred, in a series of spurts from April to September.

Though seeing a six-tailed space rock is a first for astronomers, the new research hints that there could be more asteroids with debris trails emanating from their center.

"In astronomy, where you find one, you eventually find a whole bunch more," Jewitt said in a statement. "This is just an amazing object to us, and almost certainly the first of many more to come."

P/2013 P5 has only lost a fraction of its mass, about 100 to 1,000 tons of dust, which represents a tiny portion of the 1,400-foot-wide (425 meters) asteroid, the scientists said.

While P/2013 P5 likely isn't a victim of a recent collision, researchers think the asteroid may be one of the leftover fragments of a much larger space rock that broke apart 200 million years ago. And the space rock likely doesn't contain any water, the scientists believe, based on previous examinations of collision fragments that were in orbits similar but have to P/2013 P5 have made it down to Earth's surface in the form of meteorites.

Source of Article: Space.com

Promising Comet ISON Gives Perplexing Performance En Route to Sun

With just one month to go before its dramatic solar rendezvous, skirting to within a hairbreadth of the surface of the sun, Comet ISON continues to befuddle observers with its performance en route to the sun.

Based on a compilation of Comet ISON observations from observers worldwide as of Oct. 24, the comet, once proclaimed as possibly the "Comet of the Century" was running approximately 1.3 magnitudes, or 3.3 times fainter, than the "official" brightness forecast issued by the Minor Planet Center in Cambridge, Mass. As the comet comes down the home stretch of its long journeybefore finally grazing to within 730,000 miles (1.2 million kilometers) of the sun, great uncertainty continues regarding whether or not it will remain disappointingly dim or whether it will end up evolving into a spectacularly bright object.        

Carl Hergenrother of the Lunar and Planetary Laboratory in Tucson, Ariz., noted that part of the uncertainty is due to what wavelengths the comet is observed in: "Visual and CCD-V observations do show a comet that is brightening at a normal rate (perhaps even faster than normal for a dynamically new comet) while CCD-R observations show a comet that is barely brightening at all. CCD-R sees predominately dust in contrast with visual and CCD-V, which have large gas components. It seems that over the past month or so ISON's gas production rate has increased as expected while its dust production rate has not," Hergenrother said. "I don't really know what this means but something has to give, either the dust production picks up or the gas production slows down." 

Looking weird

The highly regarded comet observer John Bortle is just as perplexed by the comet's recent appearance, commenting that the recent images along with his own visual impression, is "downright weird." He adds that, "There is a bright, miniature, long-tailed comet situated within a much larger, but very much fainter and diffuse halo of a coma."

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Those visual people using larger telescope also often remark about the odd way the comet looks, while those using relatively small scopes and big binoculars report seeing a larger, more-or-less faint but uniform cometary mass," he added. "This comet is currently at a distance from the sun where it should no longer exhibit such a dichotomy of appearance.” 

Bortle has observed several hundred comets and yet, he writes, "At this stage of the game, with the comet about to cross the orbit of Earth, I cannot recall any previous comet in my 50-plus years of comet observing looking quite like this. So, what does ISON's current look foretell, or mean? I honestly don't know. All I can say is I don't like the odd look of it at this time."

One step forward, one step back

Around Oct. 19, ISON seemed to suddenly brighten at a more rapid pace. On Oct. 21, Arizona observer Bruce Gary (who was the first to image the comet after it emerged from out of the glare of the sun on Aug. 12) wrote, "The comet (coma plus tail) continues a dramatic brightening trend that started Oct 19. The inner coma has brightened (due perhaps to an outburst of gases). This next week could be busy - and exciting!"

But just four days later, with the comet showing signs of fading a bit rather than brightening, Gary, sounding almost a bit exasperated commented, "I don't know what's going on with this comet!"

Analyzing all the observations made since Sept. 4 shows that ISON is responding to the sun more like a solid body would respond, rather than as a typical "fluffy" comet. 

Time Running Out

Whatever is happening, Comet ISON continues on its way in toward the sun and will cross the Earth's orbit on Wednesday (Oct. 30) at 6 p.m. EDT (22:00 GMT). 

For the last couple of months, observers watching the comet brighten at what has seemed to be a frustratingly slow pace are still waiting for a more rapid brightening trend. That may still happen, but time is now running out; four weeks from Thursday will be the comet's moment of truth as it whips around the sun.

Will it remain disappointingly dim? Will it finally brighten up? Will it still be completely intact when it sweeps back out into space or will the sun's extreme heat and tremendous tidal forces cause it to fracture into several pieces? At SPACE.com we will continue to monitor the comet's future behavior and provide any new updates in the days to come, so stay tuned!

Source of Article: Space.com

Russian Fireball Explosion Shows Meteor Risk Greater Than Thought

As researchers recover more leftover pieces from the space rock that detonated earlier this year near the Russian city of Chelyabinsk, the event is helping to flag a worrisome finding: Scientists have misjudged the frequency of large airbursts.

Computer simulations also imply that such airbursts cause more damage than nuclear explosions of the same yield, which are typically used as an analogue to ballpark impact risk.

The meteor explosion over Chelyabinsk gives the bottom-line message that the risk from airbursts is greater than previously thought.

Meteor explosion data points

Mark Boslough, a physicist at Sandia National Laboratories in New Mexico, broached the implications of the Chelyabinsk airburst event on Oct. 7 here at the American Astronomical Society's 2013 Division for Planetary Sciences meeting.

According to Boslough, when you add the Chelyabinsk incident to the 1908 Tunguska explosion over Siberia — along with a 1963 bolide blast near the Prince Edward Islands off the coast of South Africa — the data suggest that the incoming rate of small space rocks is actually much higher than asteroid experts have assumed based on astronomical observations. 

That Prince Edward Islands event was a 1.1-megaton explosion picked up by a global network of infrasound sensors, but not apparently seen by any observers.

"These three data points together suggest that maybe we have underestimated the population," of smaller sized objects that can create air bursts, Boslough said. "We think the airburst hazard is greater than previously thought."

Chelyabinsk consortium

The Feb. 15, 2013, explosion of a previously undetected asteroid about 25 miles (40 kilometers) from the Russian city of Chelyabinsk led to many injuries and widespread blast damage. But it has also spurred a wealth of data helping scientists to gauge the object's size, angle of entry and other specifics, Boslough said.

A "Chelyabinsk consortium" has been hard at work to better discern the varied characteristics of the fireball and the subsequent damage, he said.

The best estimate places the explosive yield of the space rock at 400 to 500 kilotons, Boslough said, making Chelyabinsk the most powerful such event observed since Tunguska, which is pegged at 3 to 5 megatons. (There are 1,000 kilotons in a megaton.)

The Chelyabinsk space intruder came in mostly from the east at 9:20 a.m. local time in Russia, bursting apart close to 19 miles (30 km) above the ground.

Pre-entry, the object had a diameter of roughly 65 feet (20 meters), with a mass of approximately 12,000 tons, Boslough said. It came in at an 18-degree angle, "a glancing blow," spreading its energy sideways and at an angle, which generated less damage on the ground, he said. Still, the outburst broke windows over several thousand square kilometers.

Out of the sun

Thanks to the work of colleague Peter Brown, a physics professor at the University of Western Ontario in Canada, Boslough said over 500 videos of the Chelyabinsk fireball have been collected, some of those no longer available via the Internet.

Boslough traveled to Chelyabinsk, where he performed calibrations of dashcam videos to help pinpoint the altitude and coordinates of the explosion.

"It came pretty much straight out of the sun," Boslough said.

Roughly 1,500 people were injured, "almost all by flying glass," due to a powerful, post-explosion shockwave, he said.

Duck and cover

On one hand, Boslough said that the old Cold War practice of "duck and cover" during a nuclear bomb drill is a bit quaint, "but it turns out that it would be the right thing to do" for the Chelyabinsk meteor.

"If you're not at ground zero, the way to keep yourself from getting hurt from a large explosion in the atmosphere is to stay away from windows," Boslough said.

But even armed with that fact, he admitted that scientific curiosity would assuredly have driven him for a look-see out the window.

"I probably know as much about airburst as anybody," Boslough said, "and I'd probably have my face pressed against the window, and as soon as the blast died down, I would have gone 'Oh, yeah.'"

Still, if scientists had discovered this asteroid before it struck, be it five months or even a week in advance, it would have been wise to send out a call for people to stay away from windows, Boslough said. 

In an October 1 online version of Acta Astronautica, a journal sponsored by the International Academy of Astronautics, Boslough has written about airburst warning and response, concluding that it is "virtually certain" that the next destructive Near Earth Object (NEO) event will be an airburst.

"Because early warning and civil defense will almost certainly be needed long before the first deflection is ever required, the credibility of the planetary defense community and its recommendations will be put to its first serious test by an airburst," Boslough said.

In his Acta Astronautica paper, Boslough has proposed an "airburst warning scale" to assist decision makers.

Misinterpreted attack

Also observing the Chelyabinsk episode, but from space, were U.S. government sensors. They, too, caught the affair, with that data released to the scientific community.

"If you compare some of these numbers to our estimates, they are different. It is worthwhile starting to consider these sorts of events as ground truth," Boslough told the DPS gathering.

Boslough underscored a concern voiced to Congress several years ago by Pete Worden, then deputy director for operations at the U.S. Space Command, now director of the NASA Ames Research Center near Silicon Valley, Calif. One of the largest potential threats associated with an airburst is the risk that it could be misunderstood as a preemptive attack launched by one country at another, Worden had said.

"I always thought that was a little exaggerated," Boslough said, until he watched a number of videos taken of the Chelyabinsk blast.

"Say that this had happened on an overcast day, where nobody actually saw the streak across the sky. Then you see smoke, hear a large explosion and a lot of things that sound like artillery fire," Boslough said. Then imagine it's over a place that's already politically unstable, he said.

"One of the biggest threats could be that this might lead to a counterattack of somebody because something was misconstrued," Boslough said.

Source of Article: Space.com

X-ray Space Telescope of the Future Could Launch in 2028

There's a big expiration date looming ahead in astrophysicist Kirpal Nandra's mind. The current X-ray space telescopes in orbit will likely be at or near the end of their lifetimes by about 2020, so plans are underway to develop a successor to keep watch on deep space.

With NASA's budget in flux, Nandra — who is with the Max Planck Institute for Extraterrestrial Physics — said Europe needs to act quickly and independently to cover the expected gap in X-ray astronomy.

Nandra will know very soon whether that's possible. He's part of a team proposing the Advanced Telescope for High-Energy Astrophysics (Athena+) concept to launch in 2028. By the end of November, the European Space Agency (ESA) will decide what science theme the mission will address, although it will take another year to decide which mission will be used.

Athena+, though a strong candidate, faces some tough competition, Nandra told SPACE.com. Since X-rays are only visible from space, this is the last chance to put something up there within the next couple of decades.

"If Athena doesn't go forward, we won't have any X-ray eyes out there looking at the hot parts of the universe, or the energetic parts of the universe, in the 2020s," Nandra said.

Lighter and more sensitive

Previously, Nandra's team came very close to an X-ray telescope concept, only to see it yanked away. The International X-ray Observatory was backed by ESA, NASA and the Japan Aerospace Exploration Agency before it was terminated in 2010. Budgetary problems within NASA caused it to pull back on IXO, Nandra said.

By contrast, Athena+ is solely European-funded and based partly on theXMM-Newton telescope in orbit right now. But there are big differences.

The design calls for silicon plates to reduce the weight of the telescope while making it bigger — allowing an Ariane 5 rocket (the biggest booster the Europeans have) to heft the 12-meter (39.4 feet) machine into orbit.

On board will be a new kind of detector — the X-Ray Integral Field Unit — that can detect a minute change in heat when a single X-ray photon is absorbed. Athena+ will also carry CALLE, an imager that can survey vast swatches of the universe at high sensitivity, but which is not limited to a narrow field of view.

"That combination is exactly what you need if you want to discover black holes growing in the deep universe, the earliest supermassive black holes," Nandra said, adding that another science goal is to understand how gas structures in the universe formed and evolved.

Ripples across the universe

With Athena+, researchers hope to learn how these giant black holes — which form in galaxies — affect the rest of the universe. They're plenty powerful: Nandra said scientists have seen these effects in collections of thousands of galaxies. In these clusters, the energy output of the black hole at the center can be seen bubbling and stirring up gas millions of light-years away.

The presence of a black hole can also stop star formation inside of a galaxy as it blows out the gas, Nandra said. "It turns an active star-forming galaxy into a passive galaxy, a process that we call cosmic feedback, and that's one of the things that we're trying to work out — how that process happens — with Athena."

Athena+ is expected to cost 1.2 billion to 1.3 billion euros ($1.6 billion to $1.8 billion), including launch costs. If it passes the competition, Athena+ will still need to meet several key design and construction milestones before launch.

ESA has accepted dozens of white papers for two launch opportunities in 2028 and 2034. Mission concepts include a planetary science infrared observatory, a mission to study Neptune and Triton, and an orbiter and lake probe for Saturn's moon Titan.

Source of Article: Space.com

Crab Nebula's Strange Pulsar Heart Slowly Going Off-Kilter

For the first time, astronomers have tracked the evolution of a pulsar's magnetic field over time, watching as it slowly tilts toward the dead star's equator. The new observations of the pulsar, located in the Crab Nebula, could offer clues to the long-standing problem of what slows pulsars' rotation.

"Most pulsars are millions or tens of millions of years old," said Andrew Lyne, emeritus professor of physics at the University of Manchester in the U.K., who led the study, which appears in the Nov. 1 issue of the journal Science. "So we don't expect to see significant changes. But we have been looking at this for a substantial portion of its lifetime, some 40 out of 1,000 years." The supernova that birthed the pulsar in the Crab Nebula occurred in A.D. 1054. Chinese and Arab astronomers both noted it.

"It's a result we've waited 30 years for," said Vasily Beskin, an astrophysicist at the Russian Academy of Sciences. Beskin, who was not involved in the study, and his colleagues predicted that pulsar magnetic fields would move to their equators in the 1980s.

Fast and slow

A pulsar is the remains of a star whose core is at least 1.4 times as massive as the sun. When such stars reach the end of their lives, they can explode as supernovae. What's left is a neutron star, only a few miles across, with a large fraction of the star's original mass, which makes them incredibly dense.

Since stars are already rotating when they collapse, the neutron star spins on its axis spectacularly fast — just as ice skaters spin faster as they pull their arms in. At the same time, the neutron star develops an intense magnetic field and emits a beam of electromagnetic radiation along the north-south axis of that field. The magnetic field's axis and the neutron star's axis of rotation aren't perfectly aligned, so the beam of radiation sweeps across space, like the rotating lamp of a lighthouse — a pulsar.

If that beam happens to cross the path of the Earth, radio telescopes can pick up the signal. The Crab Nebula pulsar's signal flashes at about 30 times per second.

The team from the University of Manchester and Jodrell Bank Observatory gathered 22 years' worth of data tracking the Crab pulsar's signals. The signal comes in two parts, a main pulse and a secondary one, called an interpulse. By measuring the polarization of the signal at two different frequencies, it's possible to calculate the angle between the axis of rotation and the beam of radiation. The researchers found that angle is increasing by 0.62 degrees per century.

Pulsar mysteries persist

Seeing how quickly this happens might offer insights as to what happens in other neutron stars, Lyne said. One of the ongoing mysteries about pulsars is why they slow down as quickly as they do. The Crab pulsar, for example, is slowing by about 38 nanoseconds per day.

"If pulsars were just rotating dipoles, we'd expect the slowdown rate to be proportional to the cube of the … rotational frequency," Lyne told SPACE.com. "We call that the braking index, and it should be about three But most pulsars are smaller than three. About two-and-a-half or so." The slow movement of the magnetic field might be the answer.

"As the inclination angle gets larger, increasing the angle between two axes, it's almost exactly at the rate you need to cause the braking index to be two-and-a-half rather than three." It still isn't clear if that's the reason, however, because the internal structure of pulsars is still poorly understood.

The new data also gave other insights. "Normally, magnetic fields don't move through superconductors," Lyne said. "This magnetic field is moving, which suggests the superconductor in the neutron star is not perfect."

It's not likely that astronomers will run across another like the Crab pulsar, because to see one at all, the radio beam has to sweep across the Earth, and the odds of one being in precisely the right orientation are small. On top of that, the supernova that made the pulsar would have to be less than a few thousand years old, scientists say. There are several supernovas of the correct age, but they aren't all the right type to produce pulsars, and even if they were, they aren't pointed the right way.

It still isn't completely clear why pulsars' magnetic fields look as they do. "I wouldn't class it as being a simple problem," Lyne said. "We're trying to understand why it should evolve in this way."

Source of Article: Space.com

Secrets of Sunday's Rare Solar Eclipse Explained

A slice of eastern North America will undergo a weird and dramatic event early Sunday (Nov. 3) morning:  a partial eclipse of the sun.

For most North American observers, the partial eclipse will coincide with sunrise.  But within a very narrow corridor that extends for 8,345 miles (13,430 kilometers) across the planet, the disks of the sun and the moon will appear to exactly coincide, providing an example of the most unusual type of eclipse: a "hybrid" or "annular-total eclipse."

During annular solar eclipse, the sun looks like a "ring of fire," while the moon and sun line up perfectly during a total eclipse. Throughout a hybrid eclipse, however, the celestial sight transitions from annular to total.

If you don't have a chance to see the eclipse from your part of the world, you can watch the cosmic rarity live on SPACE.com courtesy of the online community observatory Slooh.com. The eclipse event begins at 6:45 a.m. EST (1515 GMT) and will run throughout the entirety of the eclipse.

A Rare Occurrence

During the 21st century approximately 4.9 percent of all central solar eclipses — those eclipses where the moon crosses directly in front of the disk of the sun — fall into the hybrid classification.

In most cases, an annular-total eclipse starts as an annular, or "ring of fire" eclipse, because the tip of the moon's dark shadow cone — the umbra — falls just short of making contact with the Earth; so the moon appears slightly smaller than the sun producing the same effect as placing a penny atop a nickel leaving a ring of sunlight shining around the moon's edge.

Then the solar eclipse transitions to total, because the roundness of the Earth reaches up and intercepts the shadow tip near the middle of the path, then finally it reverts back to annular toward the end of the path. 

However, as pointed out by the renowned Belgian eclipse calculator, Jean Meeus, the hybrid eclipse of Nov. 3 will be a special case: here the eclipse starts out as annular, then after only 15-seconds it will transition to a total eclipse, and then it remains total up to the very end of the eclipse path. The last time this happened was on Nov. 20, 1854 and the next such case after 2013 will occur on Oct. 17, 2172.   

Diamond necklace, then totality

At the very beginning of this eclipse track, the tip of the umbra is literally scratching at the surface of the Earth; sitting on the borderline between annular and total it is, for all intents and purposes, a total eclipse with zero duration or ever-so-slightly more after the first 15-seconds of its interaction with our planet. 

And yet, whether the umbra touches the Earth's surface at the very beginning of the eclipse track – or barely misses — is somewhat irrelevant. Because the silhouette of the moon is not a perfect circle, but rather slightly prickly with mountains, so just before the transition from annular to total, the eclipse will become something neither annular nor total: for a few precious seconds it will be a broken annular.

As lunar mountains protrude onto the hairline-thin ring of the sun, it will be seen not as an unbroken ring but an irregular, changing, sparkling sequence of arcs, beads and diamonds very briefly encircling the moon: a "diamond necklace" effect! 

One might witness this highly unusual sight from a particular spot in the Atlantic Ocean — probably measuring less than a mile or two in width — some 405 miles (650 km) southwest of Bermuda.  At least one group of ardent eclipse watchers from Germany hope to fly above any possible ocean cloudiness to experience this event.

Sweeping rapidly southeast, the eclipse will rapidly transition to a total eclipse; the totality path will slowly widen and the duration of totality will gradually increase, although the shadow will remain out over open ocean water for 165 minutes before finally making its first landfall at Gabon.  

Along the way, the point of greatest eclipse is reached at 12:46:28 UT over the tropical eastern Atlantic, at a point 204 miles (328 km) southwest of Monrovia, Liberia.  At maximum at mid-path, totality lasts 1 minute 39.6 seconds and the path is 36 miles (57.5 km) wide.

The umbra's first landfall comes at 13:50:21 UT at the remote Wonga-Wongue Presidential Reserve, a tract of rain forest on the coast of the central African nation of Gabon. Here, on the center line, the total eclipse will last 1 min 08 sec, with the sun standing 47 degrees high in the southwest sky. 

During the next 37 minutes, the path continues out across equatorial Africa as its width and central duration again dwindle.  Sliding east-northeast, it will cut through six more African nations.  The first two are The Congo and the Democratic Republic of the Congo (known between 1971 and 1997 as the Republic of Zaire).

The path then cuts across a small slice of sparsely populated northern Uganda and northern Kenya and as it is nearing its end, crosses over into southern Ethiopia.  Finally, just before the umbra leaves the Earth at sunset over west-central Somalia at 14:27 UT, an exceedingly short total phase predicted to last for less than a second!  As was the case at the sunrise part of the path three hours and 22 minutes earlier, fortuitous observers who might have access to a clear horizon toward the west-southwest might witness the setting sun again taking on the appearance of "a diamond tiara." 

Detail on the Partial Eclipse

As was noted earlier, only a slice of eastern North America will see a partial solar eclipse, while most of the rest of the continent will see nothing of this event.  If you have an atlas, draw a line starting from a point at Sudbury, Ontario south to Port St. Joe, Florida.  All places to the left (or west) of this line will not have any view of the eclipse.  Meanwhile, those localities to the right (or east) of the line will be able to see at least a part of this eclipse at sunrise, although for those places in the immediate vicinity of this line, the moon's "bite" out of the lower edge of the sun will be tantalizingly small. 

For example, while the eclipse will not be visible from Detroit, only about 100 miles to the southeast at Cleveland, the edge of the moon's dark silhouette will be evident on the sun's lower limb as it rises above the east-southeast horizon at 7 a.m. EST (1100 GMT); the moon will obscure only about 15 percent of the sun's diameter, or just about 7 percent of the total disk area of the sun.  The "eclipse" -- if we can charitably call it that – will come to an end just nine minutes later. 

As one heads farther east, the eclipse will last longer and this slight dent will evolve into a more noticeable scallop out of the sun's lower rim.  From Pittsburgh, the eclipse will last 29 minutes from the time of local sunrise (6:51 a.m. EST), with about 29 percent of the sun's diameter darkened when it first emerges from above the horizon.

From New England, Sunday's eclipse will mark the end of a nearly 13-year long solar eclipse drought; the last time a solar eclipse was visible from this part of the U.S. was on Christmas Day in the year 2000.  From Boston, weather permitting, a most unusual sunrise will occur at 6:22 a.m. EST, with nearly 63 percent of the sun's diameter hidden behind the moon; the sun's lower right portion will be covered.  Fifty two minutes later, the last trace of the moon will disappear at the bottom of the solar disk.

From Hamilton, Bermuda, nearly 90 percent of the sun's diameter will be eclipsed, maximum eclipse coming at 7:07 a.m. AST.  San Juan, Puerto Rico will see 69 percent coverage at 7:04 a.m. AST.   

Full prediction details for many cities are available through NASA.

This information, courtesy of NASA astronomer, Fred Espenak, is given in Universal Time.  The sun's altitude and azimuth, the eclipse magnitude (fraction of the sun's diameter occulted by the Moon), and obscuration (fraction of the sun's area occulted by the Moon) are all given for the instant of maximum eclipse. 

Remember that Daylight Saving Time ends at 2 a.m. on Sunday morning!  You must set your clocks back one hour to return to standard time.  If you fail to do this, you'll be too early by one hour for viewing the eclipse.

A Google map shows the path of the eclipse and you can zoom into it and click at any location to see your local circumstances.

Be Careful!

Once again it needs repeating: to look at the sun without proper eye protection is dangerous.

If you live in the zone where it will be visible, no doubt early on Sunday morning the eclipse will top the local news, followed of course by the usual dire warnings to the public not to risk blindness by carelessly looking at it.  This has given most people the idea that eclipses are dangerous.  Not so. It's the sun that's dangerous — all the time. Ordinarily, we have no reason to gaze at it.  An eclipse gives us a reason, but we shouldn't. 

There are some safe ways, however . . . 

The only recommended safe filters – those known to block invisible but damaging infrared and ultraviolet rays – are a rectangular arc welder's glass that dims the sun comfortably in visual light (shade #14 for a normal bright sun) or a metalized filter such as Mylar made specifically for sun viewing. On a telescope, binoculars, or camera, the filter must be attached securely over the front of the instrument, never behind the eyepiece. 

The safest way to watch is by means of projecting the sun's image onto a white sheet of paper or cardboard.  Poke a small hole in an index card with a pencil point and hold a second card two or three feet behind it. The projected image will undergo all the phases of the eclipse.  A large hole makes the image bright, but fuzzy; a smaller hole makes it dim but sharp.  You can also enclose this setup in a box to keep out as much daylight as possible.  

For a nice, sharp image some have used a tiny pinhole pierced in aluminum foil. 

A leafy tree can form a profusion of natural pinhole projectors.  Watch the dappled ground in the shadow of a tree for images depicting the eclipsed sun instead of the usual round disks.

Better yet, make use of a "pinhole mirror" by covering a pocket mirror with a piece of paper that has a ¼-inch hole punched in it, and then reflect a spot of sunlight onto a nearby wall.  The image will be one inch across for every 9 feet from the mirror.  Of course, don't let anyone look at the sun in the mirror!

Of course, telescopes and binoculars can project a much larger, sharper and brighter image of the sun which can also show any sunspot groups that may be present.  Just be sure no one looks at the sun through the instrument! 

Source of Article: Space.com