Yes, This is Actually the Shadow of Io Passing Across the Surface of Jupiter.

The JunoCam onboard NASA’s Juno spacecraft continues to provide we Earthbound humans with a steady stream of stunning images of Jupiter. We can’t get enough of the gas giant’s hypnotic, other-worldly beauty. This image of Io passing over Jupiter is the latest one to awaken our sense of wonder.

This image was processed by Kevin Gill, a NASA software engineer who has produced other stunning images of Jupiter.

Continue reading “Yes, This is Actually the Shadow of Io Passing Across the Surface of Jupiter.”

Two Solar Eclipses Seen From the Surface of Mars by Curiosity

Ever since the Curiosity rover landed on Mars in 2012, it has provided NASA scientists with invaluable data about the planet’s past, as well as some breathtaking images of the planet’s surface. Much like its predecessors, the Spirit and Opportunity rover, many of these images have shown what it is like to look up at the sky from the surface of Mars and witness celestial events.

Of these events, one of the most intriguing has to be the many Martian solar eclipses that have taken place since the rover’s landed. Last month, the Curiosity rover witnessed two eclipses as the moons of Phobos and Deimos both passed in front of the Sun. These latest eclipses will allow scientists to fine-tune their predictions about Mars’ satellites and how they orbit the Red Planet.

Continue reading “Two Solar Eclipses Seen From the Surface of Mars by Curiosity”

Incredible Solar Eclipse Images From Our Readers

Holy moly, that was awesome! Incredible, fantastic, amazing…there just aren’t the words to describe what it is like to experience totality. While I’m trying to come down to Earth and figure out how to explain how wonderful this was, enjoy the beautiful images captured by our readers from across the US and those from across the world who traveled to capture one of nature’s most spectacular events: a total solar eclipse.

The images from those seeing partial eclipses are wonderful, as well, and we’ll keep adding them as they come in (update, we just got some from Europe too). Great job everyone!

Eclipse panorama. Got some cool Baily’s Beads and that prominence is nuts! Shot at 2000mm on an old Celestron 8in telescope! Credit and copyright: Kenneth Brandon.

2017 Solar Eclipse from Clayton GA, USA.
Celestron C8 Telescope on CGEM. Canon T3i (Modified IR enhanced), Solar Filter. Credit and copyright: Michael Bee.

The August 21, 2017 total solar eclipse over the Grand Tetons as seen from the Teton Valley in Idaho, near Driggs. ..This is from a 700-frame time-lapse and is of second contact just as the diamond ring is ending and the dark shadow of the Moon is approaching from the west at right, darkening the sky at right, and beginning to touch the Sun. The peaks of the Tetons are not yet in the umbral shadow and are still lit by the partially eclipsed Sun. ..With the Canon 6D and 14mm SP Rokinon lens at f/2.5 for 1/10 second at ISO 100. Credit and copyright: Alan Dyer.

Total Solar Eclipse, August 21, 2017 as seen from Tellico Plains, Tennessee. New City Expedition, photo by Igor Kuskovsky.

Total Solar Eclipse, Aug. 21, 2017, as seen from Charleston, South Carolina. Credit and copyright: Jason Major

Partial Eclipse montage from Charlottesville, Virginia. Credit and copyright: David Murr.

Partial Solar Eclipse August 21st 2017, as seen from Fullerton California USA. Sky: Partially Cloudy. Telescope: Nexstar 102 SLT Refractor, Camera: Fujifilm X-T1 @ Prime Focus. Credit and copyright: Jimmy CD.

From the total solar eclipse as seen in Columbia, Missouri, on Aug. 21, 2017. Credit and copyright: Wildhaven Creative.

Total Eclipse from Shaw Air Force Base (August 21, 2017). It was magical. Credit and copyright: Michael Seeley.

Partial solar eclipse, seen from the west coast of France, August 21, 2017. Credit and copyright: Frank Tyrlik.

Great American Eclipse, 21-08-2017. Silver Falls Oregon 10:17-10:19 local time. Raw straight out of the camera. 65mm Refractor / Canon 700D. Credit and copyright: Alexandra Hart.

“Eclipse Across America:” Could This Event Bring Us All Together?

If you are looking forward to the August 21 solar eclipse as much as we are, you’ll want to check out a new series on CuriosityStream called “Eclipse Across America.”

The four-part series takes an inside preview at this highly anticipated event. NASA experts, an international group of astronomers and seasoned eclipse chasers reveal secret viewing spots and tips on how to safely view what could be for millions of people a once-in-a-lifetime opportunity to see one of the most spectacular sights in nature: a total solar eclipse.

Our friend and Astronomy Cast co-host Dr. Pamela Gay, who is also the Director of Technology at the Astronomical Society of the Pacific, is part of the all-star “astronomy cast” (pun intended) of experts, and she talked with us about her part in the show.

“I get to talk about the really cool parts of an eclipse, where you can experience totality and actually feel the temperature change,” she said. Using state-of-the-art special effects, Pamela gets to show off what the eclipse will likely look like at spots around her location in the St. Louis, MO area. “There’s the fickleness of it, where some buildings will see totality and another won’t,” she said. “Of course, the closer you get to the centerline the longer totality will be, and there are some beautiful locations where you can see it.”

A special effects image from CuriosityStream showing how the solar eclipse could look in St. Louis, Missouri. Credit: CuriosityStream.

The really fun part of this particular eclipse is that it takes a path across the entire continental U.S. I asked Pamela if, given the rather divisive political and social climate these days in this country, could this total solar eclipse become a possible unifying moment?

“I think that during the event there will be a lot of overwhelming experiences that people sometimes have of being in a crowd – such as will there be enough bathrooms,” she said. “But afterwards, I think it will be this shared ‘do you remember when’ moment that we’ll have for the rest of our lives. We all have certain moments that we remember and currently here in the US a lot of those memories are ‘where were you when 911 happened? Or where were you when we started bombing Iraq.’ This will be ‘where you when the sun was eclipsed,’ and that is so much better than ‘where were you when the towers fell down.’”

If you already have a CuriosityStream account, you can watch the series starting with Episode One here. If you don’t, you can take advantage of a 7-day free trial in order to watch this series, and all the other great science offerings available, such as Stephen Hawking’s Universe, Brian Cox’s Wonders of Life, and other topics from astronomy observing tips to info about various missions to theoretical physics. Check it out. If you’re interested in continuing after your free trial, the ad-free streaming service costs $2.99, $5.99 and $11.99 per month for standard definition, high definition, and ultra high definition 4K respectively.

Standford Team Creates mDOT, a Mini-Starshade for Exoplanet Research

NASA has turned a lot of heads in recent years thanks to its New Worlds Mission concept – aka. Starshade. Consisting of a giant flower-shaped occulter, this proposed spacecraft is intended to be deployed alongside a space telescope (most likely the James Webb Space Telescope). It will then block the glare of distant stars, creating an artificial eclipse to make it easier to detect and study planets orbiting them.

The only problem is, this concept is expected to cost a pretty penny – an estimated $750 million to $3 billion at this point! Hence why Stanford Professor Simone D’Amico (with the help of exoplanet expert Bruce Macintosh) is proposing a scaled down version of the concept to demonstrate its effectiveness. Known as mDot, this occulter will do the same job, but at a fraction of the cost.

The purpose behind an occulter is simple. When hunting for exoplanets, astronomers are forced to rely predominantly on indirected methods – the most common being the Transit Method. This involves monitoring stars for dips in luminosity, which are attributed to planets passing between them and the observer. By measuring the rate and the frequency of these dips, astronomers are able to determine the sizes of exoplanets and their orbital periods.

As Simone D’Amico, whose lab is working on this eclipsing system, explained in a Stanford University press statement:

“With indirect measurements, you can detect objects near a star and figure out their orbit period and distance from the star. This is all important information, but with direct observation you could characterize the chemical composition of the planet and potentially observe signs of biological activity – life.”

However, this method also suffers from a substantial rate of false positives and generally requires that part of the planet’s orbit intersect a line-of-sight between the host star and Earth. Studying the exoplanets themselves is also quite difficult, since the light coming from the star is likely to be several billion times brighter than the light being reflected off the planet.

The ability to study this reflected light is of particular interest, since it would yield valuable data about the exoplanets’ atmospheres. As such, several key technologies are being developed to block out the interfering light of stars. A spacecraft equipped with an occulter is one such technology. Paired with a space telescope, this spacecraft would create an artificial eclipse in front of the star so objects around it (i.e. exoplanets) can be clearly seen.

But in addition to the significant cost of building one, there is also the issue of size and deployment.  For such a mission to work, the occulter itself would need to be about the size of a baseball diamond – 27.5 meters (90 feet) in diameter. It would also need to be separated from the telescope by a distance equal to multiple Earth diameters and would have to be deployed beyond Earth’s orbit.  All of this adds up to a rather pricey mission!

Artist’s impression of the mDOT system. Much like the moon in a solar eclipse, one spacecraft would block the light from the star, allowing the other to observe objects near that star. Credit: Space Rendezvous Laboratory/Stanford University

As such, D’Amico – an assistant professor and the head of the Space Rendezvous Laboratory (SRL) at Stanford – and and Bruce Macintosh (a Stanford professor of physics) teamed up to create a smaller version called the Miniaturized Distributed Occulter/Telescope (mDOT). The primary purpose of mDOT is to provide a low-cost flight demonstration of the technology, in the hopes of increasing confidence in a full-scale mission.

As Adam Koenig, a graduate student with the SRL, explained:

“So far, there has been no mission flown with the degree of sophistication that would be required for one of these exoplanet imaging observatories. When you’re asking headquarters for a few billion dollars to do something like this, it would be ideal to be able to say that we’ve already flown all of this before. This one is just bigger.”

Consisting of two parts, the mDOT system takes advantage of recent developments in miniaturization and small satellite (smallsat) technology. The first is a 100-kg microsatellite that is equipped with a 3-meter diameter starshade. The second is a 10-kg nanosatellite that carries a telescope measuring 10 cm (3.937 in) in diameter. Both components will be deployed in high Earth orbit with a nominal separation of less than 1,000 kilometers (621 mi).

With the help of colleagues from the SRL, the shape of mDOT’s starshade was reformulated to fit the constraints of a much smaller spacecraft. As Koenig explained, this scaled down and specially-designed starshade will be able to do the same job as the large-scale, flower-shaped version – and on a budget!

Simone D’Amico’s Space Rendezvous Laboratory, pictured inside the room where they test space navigation in highly realistic illumination conditions. Credit: Space Rendezvous Laboratory/Stanford University

“With this special geometric shape, you can get the light diffracting around the starshade to cancel itself out,” he said. “Then, you get a very, very deep shadow right in the center. The shadow is deep enough that the light from the star won’t interfere with observations of a nearby planet.”

However, since the shadow created by mDOT’s starshade is only tens of centimeters in diameter, the nanosatellite will have do some careful maneuvering to stay within it. For this purpose, D’Amico and the SRL also designed an autonomous system for the nanosatellite, which would allow it to conduct formation maneuvers with the starshade, break formation when needed, and rendezvous with it again later.

An unfortunate limitation to the technology is the fact that it won’t be able to resolve Earth-like planets. Especially where M-type (red dwarf) stars are concerned, these planets are likely to orbit too close to their parent stars to be observed clearly. However, it will be able to resolve Jupiter-sized gas giants and help characterize exozodiacal dust concentrations around nearby stars – both of which are priorities for NASA.

In the meantime, D’Amico and his colleagues will be using the Testbed for Rendezvous and Optical Navigation (TRON) to test their mDOT concept. This facility was specially-built by D’Amico to replicate the types of complex and unique illumination conditions that are encountered by sensors in space. In the coming years, he and his team will be working to ensure that the system works before creating an eventual prototype.

Artist’s concept of the prototype starshade, a giant structure designed to block the glare of stars so that future space telescopes can take pictures of planets. Credit: NASA/JPL

As D’Amico said of the work he and his colleagues at the SNL perform:

“I’m enthusiastic about my research program at Stanford because we’re tackling important challenges. I want to help answer fundamental questions and if you look in all current direction of space science and exploration – whether we’re trying to observe exoplanets, learn about the evolution of the universe, assemble structures in space or understand our planet – satellite formation-flying is the key enabler.”

Other projects that D’Amico and the SNL are currently engaged in include developing larger formations of tiny spacecraft (aka. “swarm satellites”). In the past, D’Amico has also collaborated with NASA on such projects as GRACE – a mission that mapped variations in Earth’s gravity field as part of the NASA Earth System Science Pathfinder (ESSP) program – and TanDEM-X, an SEA-sponsored mission which yielded 3D maps of Earth.

These and other projects which seek to leverage miniaturization for the sake of space exploration promise a new era of lower costs and greater accessibility. With applications ranging from swarms of tiny research and communications satellites to nanocraft capable of making the journey to Alpha Centauri at relativistic speeds (Breakthrough Starshot), the future of space looks pretty promising!

Be sure to check out this video of the TRON facility too, courtesy of Standford University:

Further Reading: Standford University

NASA to Use Converted Bombers to Chase Totality

WB57B total solar eclipse
A NASA WB-57F on the ramp at Ellington Field near Houston ready to chase totality next month during the historic August 21st total solar eclipse. Credit: NASA/JSC

In a classic swords-to-plowshares move, two converted WB-57F aircraft flown by NASA’s Airborne Science Program will greet the shadow of the Moon as it rushes across the contiguous United States on Monday, August 21st on a daring mission of science.

“We are going to be observing the total solar eclipse with two aircraft, each carrying infrared and visible light cameras taking high definition video,” Southwest Research Institute (SwRI) Principal Investigator on the project Amir Caspi told Universe Today. “These will be the highest quality observations of their kind to date, looking for fast dynamic motion in the solar corona.”

Total solar eclipses provide researchers with a unique opportunity to study the solar corona – the ghostly glow of the Sun’s outer atmosphere seen only during totality. NASA plans a battery of experiments during the eclipse, including plans to intercept the Moon’s shadow using two aircraft near the point of greatest totality over Carbondale, Illinois. Flying out of Ellington Field near Houston Texas and operated by NASA’s Johnson Spaceflight Center, NASA is the only remaining operator of the WB-57F aircraft.

NASA fleet total solar eclipse
Group photo of NASA’s three WB-57F aircraft fleet. Credit: NASA/Robert Markowitz

Flying at an altitude of 50,000 feet, the aircraft will intercept the 70 mile wide shadow of the Moon. The shadow will be moving at 1,400 miles per hour – twice the speed of sound – versus the WB-57F aircraft’s max speed of 470 miles per hour. The flight will extend the length of totality from the 2 minutes 40 seconds seen on the ground, to a total of about 8 minutes between the two aircraft.

The two converted WB-57F Canberra tactical bombers will track the eclipse using DyNAMITE (Day Night Airbourne Motion Imagery for Terrestrial Environments), two tandem gimbal-mounted 8.7-inch imagers, one for visible light and one for infrared. These are located in the nose of the aircraft and will shoot 30 frames per second.

DyNAMITE
The new DyNAMITE system mounted in the nose of NASA’s WB-57F aircraft. Credit: NASA/Amir Caspi

This system was originally designed about a decade ago to chase down the U.S. Space Shuttle during reentry following the 2003 Columbia disaster and has, on occasion, provided amazing footage SpaceX Falcon-9 Stage 1 returns during reentry.

DyNAMITE total solar eclipse
The WAVE system, a precursor to DyNAMITE, seen up close. NASA/JSC

The solar corona is about as bright as the Full Moon, and the team plans to make a precise ‘map’ of the solar corona in an effort to understand just how the corona interacts with the solar photosphere and the chromosphere. Of particular interest is understanding how wave energy and ‘nanoflares’ heat the solar corona.

“What we’re hoping to learn is what makes the corona so hot, with temperatures of 1 to 2 million degrees Celsius — or even 4 to 10 million degrees Celsius in some regions — far hotter than the photosphere below,” Caspi told Universe Today. “What keeps it organized in terms of structure? Why don’t we see a snarled, tangled mess?”

As a secondary objective, the team will also make observations of the planet Mercury in the infrared 30 minutes before and after totality, located 11 degrees to the east of the Sun during the eclipse. Mercury never strays far from the Sun, making it a tough target to study in the infrared as seen from the Earth.

Totality total solar eclipse
Totality! Credit: Alan Dyer/Amazing Sky Photography.

And of course, all of this has to happen during the scant few minutes up to and during totality. Each aircraft will fly just inside opposite ends of the shadow of the Moon in a challenging long distance precision formation.

The WB-57F aircraft will also participate in a tertiary objective, hunting for Vulcanoid asteroids near the Sun during the eclipse. Though the 19th century idea of a tiny inter-Mercurial world perturbing Mercury’s orbit was banished to the dust bin of astronomical history by Einstein’s general theory of relativity, there’s still room for undiscovered asteroids dubbed ‘Vulcanoids’ close in to the Sun. NASA flew observations hunting for Vulcanoids aboard modified F-18 Hornet aircraft in 2002 scanning twilight realms near the Sun, and came up with naught.

Eclipse chaser Landon Curt Noll noted during an interview with Universe Today in 2015 that NASA’s Solar Heliospheric Observatory SOHO mission has pretty much ruled out objects brighter than +8th magnitude near the Sun, which translates into asteroids 60 kilometers in diameter or larger.

“We have searched down to magnitude +13.5,” Noll told Universe Today. “Assuming the objects are ‘Mercury like’ in reflectivity (in) the Vulcanoid zone (0.08 to 0.18 AU from the Sun), the search has looked for and failed to find objects as small as 2 to 6 kilometers in diameter.” NASA’s Mercury Messenger carried out a similar search en route to the innermost planet.

Stellarium total solar eclipse
Mercury versus the Sun during totality. Credit: Stellarium.

Knoll has scoured the sky near the eclipsed Sun with a specialized near-infrared telescope rig during the 2006 total solar eclipse over Libya. Next month, he plans to continue his quest from a site near Jackson Hole, Wyoming.

The action leading up to the the long awaited August 21st total solar eclipse begins at 17:16 Universal Time (UT)/ 10:16 AM Pacific Daylight Saving Time (PDT), when the Moon’s dark inner shadow or umbra touches down along the Oregon Pacific coast. From there, the 70 mile wide shadow will race eastward, gracing 14 states (just nicking Iowa and Montana) before departing land over the Atlantic coast of South Carolina 92 minutes later. Viewers along the path will witness a maximum totality of 2 minutes and 40 seconds, centered on a location very near Carbondale, Illinois. Millions are expected to make the pilgrimage to the eclipse path, while those outside the path in the remainder of North America as well as northern South America, western Africa, Europe and northeast Asia will see varying levels of a partial solar eclipse.

eclipse maps total soalar eclipse
The August 21st total solar eclipse over the United States. Credit: Michael Zeiler/Eclipse Maps

This is the end of a long “total solar eclipse drought” for the United States, marking the first time totality touched the continental United States since February 26, 1979, (totality crossed Hawaii on July 11th, 1991). The last total solar eclipse to cross the United States from coast-to-coast was June 8th, 1918.

NASA has a long history of airborne astronomy campaigns. Noll notes that NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) flying observatory based out of Armstrong research center would make an ideal platform for Vulcanoid hunting during totality. Looking at SOFIA’s flight schedule, however, reveals no plans to carry out such a chase on August 21st. SOFIA’s predecessor, the Kuiper Observatory built into a U.S. Air Force C-141 Starlifter discovered the rings of Uranus during a stellar occultation in 1977.

“This is the first use of DyNAMITE and NASA’s WB-57F platform for astronomy,” Caspi told Universe Today. “This showcases the potential for the platform for possible future observations.”

The DyNAMITE/WB-57B campaign will also be part of the live NASA TV webcast on eclipse day.

Airborne total solar eclipse chasing goes all the way back to August 19th 1887, when Dmitri Mendeleev (he of the periodic table) observed totality from aloft. There’s a great old video of an effort to chase a 1925 total solar eclipse using the airship the USS Los Angeles:

A team also chased a total solar eclipse across North Africa on June 30th, 1973 aboard a supersonic Concorde:

Today, you can even book a ticket for an eclipse-chasing experience aloft. Alaska Airlines plans to attempt to duplicate its 2016 success, and will once again chase totality with a lucky few observers aboard next month.

As for us, we’re planning on watching the eclipse from terra firma at the Pisgah Astronomical Research Institute (PARI) in North Carolina while intrepid researchers fly high above. Watch for our complete eclipse guide out around July 21st on Universe Today and an update on weather prospects, solar activity etc. about a week prior. Finally, we’ll have an after action report out post total solar eclipse, with reader images from across the country.

-This promises to be a total solar eclipse for the ages. Don’t miss the Great American Eclipse!

-Also, be sure to check out the Eclipse MegaMovie Project.

-Read more about the August 21st total solar eclipse and the true tale of Vulcan, Totality and Edison’s Chickens in our free e-guide to 101 Astronomical Events for 2017, out from Universe Today.

-Be sure to read our original tales of eclipse science fiction.

Weekly Space Hangout – June 2, 2017: Mike Simmons of Astronomers Without Borders

Host: Fraser Cain (@fcain)

Special Guest:
Mike Simmons is the President of Astronomer Without Borders. Mike is joining us today to discuss how AWB will be engaging the public and our schools both during and following the total solar eclipse on August 21, 2017. You can find the AWB Eclipse education program website here.
If you’d like to purchase eclipse glasses from AWB, all of the proceeds go to science education programs! Order here!

Guests:

Sarah Marquart (Futurism.com / @SagaofSarah)
Brian Koberlein (briankoberlein.com / @BrianKoberlein)

Their stories this week:

Tomorrow, SpaceX Will Transform Spaceflight Forever

NASA Just Unveiled Their Next Mission “We Will Finally Touch the Sun”

Lunar Observer Struck by Meteoroid

Testing Gravitons With BH Mergers

We use a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

Announcements:

The WSH recently welcomed back Mathew Anderson, author of “Our Cosmic Story,” to the show to discuss his recent update. He was kind enough to offer our viewers free electronic copies of his complete book as well as his standalone update. Complete information about how to get your copies will be available on the WSH webpage – just visit http://www.wsh-crew.net/cosmicstory for all the details.

If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page

Astronomy Cast Ep. 448: Prepping for the Eclipse

On Monday, August 21, 2017, there’s going to be a total eclipse of the Sun, visible to path that goes right through the middle of the United States. You should be making plans to see this, and we’re here to help you know where to go and what to do.
Visit the Astronomy Cast Page to subscribe to the audio podcast!

We usually record Astronomy Cast as a live Google+ Hangout on Air every Friday at 1:30 pm Pacific / 4:30 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.

Weekly Space Hangout – April 28, 2017: Tim Blais of A Capella Science

Host: Fraser Cain (@fcain)

Special Guest:
Tim Blais is the founder of A Capella Science, an “educational and utterly nerdy online video project.” You can find his videos online on YouTube at A Capella Science.

Guests:
Jolene Creighton (fromquarkstoquasars.com / @futurism)

Their stories this week:
Total Eclipse of the Sun to be commemorated on a Forever Stamp

Kepler Stares at Neptune (NASA Video)

New Horizons 2.0

Joint mission to Europa could seek life under the ice

We use a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

Announcements:
On Friday, May 12, the WSH will welcome authors Michael Summers and James Trefil to the show to discuss their new book, Exoplanets: Diamond Worlds, Super Earths, Pulsar Planets and the New Search for Life Beyond Our Solar System. In anticipation of their appearance, the WSH Crew is pleased to offer our viewers a chance to win one of two hard cover copies of Exoplanets. Two winners will be drawn live by @fraser during our show on May 12th. To enter for a chance to win a copy of Exoplanets, send an email to: [email protected] with the Subject: Exoplanets. Be sure to include your name and email address in the body of your message so that we can contact the winners afterward. All entries must be electronically postmarked by 23:59 EST on May 10, 2017, in order to be eligible. No purchase necessary. Two winners will be selected at random from all eligible entries. Good luck!

If you’d like to join Fraser and Paul Matt Sutter on their Tour to Iceland in February 2018, you can find the information at astrotouring.com.

If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page<

See a Flirtatious Lunar Eclipse This Friday Night

This sequence of photos taken on October 18, 2013 nicely show the different phases of a penumbral lunar eclipse. The coming penumbral eclipse will likely appear even darker because Earth’s shadow will shade to the top (northern) half of the Moon rich in dark lunar “seas” at maximum. Credit: AstroTripper 2000

Not many people get excited about a penumbral eclipse, but when it’s a deep one and the only lunar eclipse visible in North America this year, it’s worth a closer look. What’s more, this Friday’s eclipse happens during convenient, early-evening viewing hours. No getting up in the raw hours before dawn.

Lunar eclipses — penumbral, partial and total — always occur at Full Moon, when the Moon, Earth and Sun line up squarely in a row in that order. Only then does the Moon pass through the shadow cast by our planet. Credit: Starry Night with additions by the author

During a partial or total lunar eclipse, the full moon passes first through the Earth’s outer shadow, called the penumbra, before entering the dark, interior shadow or umbra. The penumbra is nowhere near as dark as the inner shadow because varying amounts of direct sunlight filter into it, diluting its duskiness.

To better understand this, picture yourself watching the eclipse from the center of the Moon’s disk (latitude 0°, longitude 0°). As you look past the Earth toward the Sun, you would see the Sun gradually covered or eclipsed by the Earth. Less sunlight would be available to illuminate the Moon, so your friends back on Earth would notice a gradual dimming of the Moon, very subtle at first but becoming more noticeable as the eclipse progressed.

This diagram shows an approximation of the Sun’s position and size as viewed by an observer at the center of the lunar disk during Friday’s penumbral eclipse. More sunlight shines across the Moon early in the eclipse, making the penumbral shadow very pale, but by maximum (right), half the sun is covered and the Moon appears darker and duskier as seen from Earth. During a total lunar eclipse, the sun is hidden completely. Credit: Bob King with Earth image by NASA

As the Moon’s leading edge approached the penumbra-umbra border, the Sun would narrow to a glaring sliver along Earth’s limb for our lucky lunar observer. Back on Earth, we’d notice that the part of the Moon closest to the umbra looked strangely gray and dusky, but the entire lunar disk would still be plainly visible. That’s what we’ll see during Friday’s eclipse. The Moon will slide right up to the umbra and then roll by, never dipping its toes in its dark waters.

During a partial eclipse, the Moon keeps going into the umbra, where the Sun is completely blocked from view save for dash of red light refracted by the Earth’s atmosphere into what would otherwise be an inky black shadow. This eclipse, the Moon only flirts with the umbra.

The moon’s orbit is tilted 5.1 degrees in relation to Earth’s orbit, so most Full Moons, it passes above or below the shadow and no eclipse occurs. Credit: Bob King

Because the moon’s orbit is tilted about 5° from the plane of Earth’s orbit, it rarely lines up for a perfect bullseye total eclipse: Sun – Earth – Moon in a straight line in that order. Instead, the moon typically passes a little above or below (north or south) of the small, circle-shaped shadow cast by our planet, and no eclipse occurs. Or it clips the outer edge of the shadow and we see — you guessed it — a penumbral eclipse.

Earth’s shadow varies in size depending where you are in it. Standing on the ground during twilight, it can grow to cover the entire sky, but at the moon’s distance of 239,000 miles, the combined penumbra and umbra span just 2.5° of sky or about the width of your thumb held at arm’s length.

The moon passes through Earth’s outer shadow, the penumbra, on Feb. 10-11. In the umbra, the sun is blocked from view, but the outer shadow isn’t as dark because varying amounts of sunlight filter in to dilute the darkness. Times are Central Standard. Credit: F. Espenak, NASA’s GFSC with additions by the author

Because the Moon travels right up to the umbra during Friday’s eclipse, it will be well worth watching.The lower left  or eastern half of the moon will appear obviously gray and blunted especially around maximum eclipse as it rises in the eastern sky that Friday evening over North and South America. I should mention here that the event is also visible from Europe, Africa, S. America and much of Asia.

This map shows where the eclipse will be visible. Most of the U.S. will see at least part of the event. Credit: F. Espenak, NASA’s GFSC

For the U.S., the eastern half of the country gets the best views. Here are CST and UT times for the different stages. To convert from CST, add an hour for Eastern, subtract one hour for Mountain and two hours for Pacific times. UT stands for Universal Time, which is essentially the same as Greenwich or “London” Time except when Daylight Saving Time is in effect:

This is a simulated view of the Full Snow Moon at maximum eclipse Friday evening low in the eastern sky alongside the familiar asterism known as the Sickle of Leo. Created with Stellarium

Eclipse begins: 4:34 p.m. (22:34 p.m. UT)
Maximum eclipse (moon deepest in shadow): 6:44 p.m. (00:43 UT Feb. 11)
Eclipse ends: 8:53 p.m. (2:53 UT Feb. 11)

You can see that the eclipse plays out over more than 4 hours, though I don’t expect most of us will either be able or would want to devote that much time. Instead, give it an hour or so when the Moon is maximally in shadow from 6 to 7:30 p.m. CST; 7-8:30 EST; 5-6:30 p.m. MST and around moonrise Pacific time.

This should be a fine and obvious eclipse because around the time of maximum, the darkest part of the penumbra shades the dark, mare-rich northern hemisphere of the Moon. Dark plus dark equals extra dark! Good luck and clear skies!