RSSArchive for December, 2011

Moon mission set to begin in New Year

Artist's impression of the GRAIL spacecraft in lunar orbit

The twin Moon-orbiting GRAIL spacecraft will map the lunar gravitational field, which scientists will use to "peer" deep beneath the Moon's surface. (Artist's impression)

  • Twin spacecraft called GRAIL
  • Will map the Moon’s gravitational field
  • Aim is to study the Moon from core to crust

NASA’S TWIN SPACECRAFT to study the Moon from crust to core are nearing their main-engine burns to place the duo into lunar orbit.

Named the Gravity Recovery And Interior Laboratory (GRAIL), the spacecraft are scheduled to be placed in orbit beginning at 8:21am Sydney time for GRAIL-A on January 1, 2012, and 9:05am for GRAIL-B the following day.

The distance from Earth to the Moon is approximately 402,000 kilometres. NASA’s Apollo crews took about three days to travel to the Moon. Launched from Cape Canaveral Air Force Station September 10, 2011, the GRAIL spacecraft are taking about 30 times that long and covering more than 4 million kilometres to get there.

This low-energy, long-duration trajectory has given mission planners and controllers more time to assess the spacecraft’s health. The path also allowed a vital component of the spacecraft’s single science instrument, the Ultra Stable Oscillator, to be continuously powered for several months. That allowed it to reach a stable operating temperature long before science measurements from lunar orbit are to begin.

Diagram of the GRAIL trajectories to the Moon

The two GRAIL spacecraft have followed long, slow trajectories to get the Moon.

“This mission will rewrite the textbooks on the evolution of the Moon,” said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology. “Our two spacecraft are operating so well during their journey that we have performed a full test of our science instrument and confirmed the performance required to meet our science objectives”.

A complex arrival

As of December 28, GRAIL-A was 106,000 kilometres from the Moon and closing at a speed of 1,200 kilometres per hour. GRAIL-B was 128,000 kilometres from the Moon and closing at a speed of 1,228 kilometres per hour.

During their final approaches to the Moon, both orbiters will move toward it from the south, flying nearly directly over the lunar south pole. The lunar orbit insertion burn for GRAIL-A will take approximately 40 minutes and change the spacecraft’s velocity by about 688 kilometres per hour.

GRAIL-B’s insertion burn 25 hours later will last about 39 minutes and is expected to change the probe’s velocity by 691 kilometres per hour.

The insertion manoeuvres will place each orbiter into a near-polar, elliptical orbit with a period of 11.5 hours. Over the following weeks, the GRAIL team will execute a series of burns with each spacecraft to reduce their orbital period from 11.5 hours down to just under two hours.

At the start of the science phase in March 2012, the two GRAILs will be in a near-polar, near-circular orbit with an altitude of about 55 kilometres.

GRAIL spacecraft in a white room before launch

The small GRAIL twins are almost identical.

Mapping the Moon’s gravity

When science collection begins, the spacecraft will transmit radio signals to each other as they orbit the Moon, enabling scientists to precisely define the distance between them.

As they fly over areas of greater and lesser gravity, caused both by visible features such as mountains and craters and by masses hidden beneath the lunar surface, they will move slightly toward and away from each other.

An instrument aboard each spacecraft will measure the changes in their relative velocity very precisely, and scientists will translate this information into a high-resolution map of the Moon’s gravitational field.

The data will allow mission scientists to understand what goes on below the surface. This information will increase our knowledge of how Earth and its rocky neighbours in the inner Solar System developed into the diverse worlds we see today.

For more information about GRAIL, click here.

Adapted from information issued by NASA / JPL-Caltech / LMSS / KSC.

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Earth from Space – Videos of our World, Pt 2

HERE ARE SOME MORE AMAZING short videos put together from images taken by astronauts aboard the International Space Station.

This first one was made from images taken on December 4, 2011, and shows a pass from just northwest of Morocco to central Kazakhstan. The first thing that can be seen is Spain and Portugal, with Lisbon lit up brightly in the foreground near the Atlantic Ocean and Madrid in the middle of Spain.

The pass continues into France, with the English Channel in the far left and the Italian Peninsula in the far right. Further down the pass and on the left video, the Baltic Sea appears as a dark patch surrounded by light as the ISS continues to the east-northeast towards Moscow, Russia. The pass continues toward central Russia before the sunrise in the east comes up.

This next one was taken November 24, 2011 and shows a pass over the South Pacific Ocean northeast to the North Atlantic Ocean, just east of Newfoundland. The video begins over the dark Pacific Ocean as the ISS travels northeast towards the western coast of Mexico. The bright lights of Mexico City can be seen left of track, along with the lights of Honduras and Guatemala just right of track.

The pass continues over the Yucatan Peninsula, where Cozumel and Merida are visible as brighter spots on the peninsula. As the ISS tracks northeast over the Caribbean Sea, southeastern United States becomes visible, with the Florida Peninsula standing out well. The city lights of the larger cities such as Miami, Tampa, and Orlando light up the peninsula. The pass ends by tracking up the eastern coast of the United States, where Washington D.C., Baltimore, and New York City stand out.

The third video was taken November 18 to 19, 2011, and shows a pass from South Africa, west of Johannesburg, to southern Pakistan. The Russian vehicle Soyuz is shown off-centre throughout the video, just days before astronauts Mike Fossum, Satoshi Furukawa, and Sergey Volkov boarded this vehicle to come back to Earth.

Near the beginning of the video, the bright lights of Johannesburg as displayed as the ISS tracks northeast up the eastern Africa coastline. A few lightning storms can also be seen near Johannesburg. As the pass continues, the Arabian Peninsula is only briefly seen in the far right of the video before the pass ends over the Arabian Sea, just south of Pakistan.

This one was taken on November 16, 2011, on a pass over the Pacific Ocean, from just west of California to just west of Costa Rica and Panama in Central America. The camera in the cupola is facing west-southwest towards North and Central America. The pass begins looking just north of the Baja Peninsula, where Los Angeles and San Diego can carefully be seen near the coast. Continuing down the Baja Peninsula and the Gulf of California, the pass continues looking into Mexico. Finally, as the cloud cover thickens, the pass closes over Central America, looking far west at Costa Rica and Honduras.

Taken on October 15, 2011, this sequence of shots shows a pass from just west of San Francisco, California over the Pacific Ocean to the southern tip of the Hudson Bay. The video begins as the ISS is just west of San Francisco flying northeast. The coastal lights distinguish the land and water here.

The pass continues northeast toward Wyoming and North Dakota, before crossing over into Canada. From here, the Aurora Borealis is seen, with an interesting looking angle from underneath the lights. A blanket of clouds covers Manitoba and Ontario as the ISS tracks closer to the Northern Lights.

This video was taken on December 4, 2011,, on a pass from just northwest of Morocco to central Kazakhstan. The first thing that can be seen is Spain and Portugal, with Lisbon lit up brightly in the foreground near the Atlantic Ocean and Madrid in the middle of Spain.

The pass continues into France, with the English Channel in the far left and the Italian Peninsula in the far right. Further down the pass and on the left video, the Baltic Sea appears as a dark patch surrounded by light as the ISS continues to the east-northeast towards Moscow, Russia. The pass continues toward central Russia before the sunrise in the east comes up.

The next video was taken on October 20, 2011, on a descending pass from eastern China to western New Guinea, and rounds out to an ascending pass just as the video ends north of Australia. As the pass begins southeastward towards the South China Sea, the first noticeably-lit area is that of Hong Kong and Macau. The island of Taiwan can also be easily seen left of track.

The ISS passes over the South China Sea towards the Philippines, which have some cloud cover and storms. Finally, the pass ends just north of Australia, where the Yorke Peninsula can be seen as a dark, rusty colour protruding into the water.

And this final video was taken on October 22, 2011, on a pass from the North Atlantic Ocean, just west of Portugal and Spain, to northwest of Mozambique in southeastern Africa. This video begins just northwest of the United Kingdom and shows the ISS travelling southeast towards Africa. The camera points at the sky, capturing clusters of stars as they seem to fly by.

Videos courtesy NASA and the Image Science and Analysis Laboratory, NASA-Johnson Space Centre.

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Gallery – NASA’s next spacecraft options

Artist's conception of the Dream Chaser spacecraft

Artist's conception of the Dream Chaser spacecraft under development by Sierra Nevada of Centennial, Colorado. Dream Chaser would launch vertically on an Atlas V rocket but land horizontally like the Space Shuttle. It aims to carry seven people into low-Earth orbit.

IN 2011, NASA SELECTED a number of companies to mature the design and development of a crew transportation system with the overall goal of accelerating a United States-led capability to the International Space Station.

The programme is called the Commercial Crew Program (CCP), part of the Commercial Crew Development Round 2 (CCDev2).

According to NASA, the goal of CCP is to drive down the cost of space travel as well as open up space to more people than ever before by balancing industry’s own innovative capabilities with NASA’s 50 years of human spaceflight experience.

Seven aerospace companies are maturing launch vehicle and spacecraft designs under CCDev2, including Alliant Techsystems Inc. (ATK); The Boeing Co.; Excalibur Almaz Inc.; Blue Origin; Sierra Nevada; and United Launch Alliance (ULA).

Artist's conception of the Dragon capsule

Artist's conception of the Dragon capsule under development by Space Exploration Technologies (SpaceX) of Hawthorne, California. The unmanned version of the Dragon capsule has already had one successful test flight. The second test flight, due for February 2012, will see it dock with the International Space Station (ISS). After that, it will go into revenue service taking cargo to the ISS. The manned version is still some years away from flight.

Artist's conception of the New Shepard spacecraft

Artist's conception of the New Shepard spacecraft under development by Blue Origin of Kent, Washington.

Artist's conception of the CST-100

Artist's conception of the CST-100 under development by The Boeing Co. of Houston. The CST-100 will be able to take up to seven astronauts to the ISS.

Artist's conceptions of the Atlas V and Liberty Launch vehicles

Artist's conceptions of a United Launch Alliance Atlas V rocket (left) and the Liberty Launch Vehicle (right) under development by Alliant Techsystems Inc., both of which are being considered for NASA's Commercial Crew Program (CCP).

Adapted from information issued by NASA.

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Comet wows earthlings and astronauts

Comet Lovejoy over Santiago de Chile

This beautiful dawn photo of Comet Lovejoy over Santiago de Chile was taken by European Southern Observatory photo ambassador Yuri Beletsky on December 22 at 5:00am.

MANY THOUGHT IT WOULDN’T SURVIVE, but a comet discovered by an Australian amateur astronomer has zipped past the Sun at an extremely close distance and lived to tell the tale.

Comet Lovejoy was discovered by Terry Lovejoy (Queensland) on November 27. It quickly became clear that it was going to pass very close to the Sun, making it a Kreutz-class sungrazing comet.

In fact, at the time of closest approach, the distance between the comet and the Sun’s surface was only 140,000 kilometres—that’s only one-third of the distance between the Earth and the Moon!

So you can see why it wasn’t expected to survive. Comets are made of a mixture of ice, dust and rock, and are fairly fragile bodies. The intense heating experienced during a close encounter with the Sun is enough to make many sungrazing comets break apart and vaporise.

But not Comet Lovejoy! It went behind the Sun (as seen from Earth) and, as luck would have it, swung back into view even more spectacular than before.

Here are a couple of videos showing the close encounter. The first is from the STEREO spacecraft, and the second is the Solar Dynamics Observatory spacecraft…both of which continually monitor the Sun.

The view from space was just as spectacular. Aboard the International Space Station, mission commander Dan Burbank captured the scene from almost 400 kilometres up, calling it “the most amazing thing I have ever seen in space”. Here’s the video:

And here’s more of what he had to say about the view:

And here’s a short time-lapse of images taken at the European Southern Observatory’s Paranal site in Chile, showing what it looked like from a dark site on the ground.

Adapted from information issued by NASA / Dan Burbank / SDO / G. Blanchard (eso.org/~gblancha) / ESO / Y. Beletski.

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First Earth-size planets orbiting a Sun-like star

Comparison of Kepler-20e and Kepler-20f with Venus and Earth

Comparison of newfound planets, Kepler-20e and Kepler-20f, with Venus and Earth from our Solar System. The two Kepler planets are the first Earth-size worlds found circling a Sun-like star elsewhere in our galaxy.

  • First Earth-size planets found orbiting another Sun-like star
  • The system is 1,000 light-years from Earth
  • Three other planets already known in this system

NASA’S KEPLER MISSION has discovered the first Earth-size planets orbiting a Sun-like star outside our Solar System. The planets, called Kepler-20e and Kepler-20f, are too close to their star to be in the so-called habitable zone where liquid water could exist on a planet’s surface, but they are the smallest exoplanets ever confirmed circling a star like our Sun.

The discovery marks the next important milestone in the search for planets like Earth.

The new planets are thought to be rocky. Kepler-20e is slightly smaller than Venus, measuring 0.87 times the radius of Earth. Kepler-20f is a bit larger than Earth, measuring 1.03 times its radius.

Both planets reside in a five-planet system called Kepler-20, approximately 1,000 light-years from Earth.

Kepler-20e orbits its parent star every 6.1 days and Kepler-20f every 19.6 days. These short orbital periods mean the planets circle close to their star, and are therefore very hot, inhospitable worlds.

Kepler-20f, at 800 degrees Fahrenheit, is similar to an average day on the planet Mercury. The surface temperature of Kepler-20e, at more than 760 degrees Celsius, would melt glass.

Earth-size planets now known to exist

“The primary goal of the Kepler mission is to find Earth-sized planets in the habitable zone,” said Francois Fressin of the Harvard-Smithsonian Centre for Astrophysics, and lead author of a new study published in the journal Nature.

“This discovery demonstrates for the first time that Earth-size planets exist around other stars, and that we are able to detect them.”

Artist's impression of Kepler-20e

Artist's impression of Kepler-20e, which is about 0.87 times the radius of Earth.

The Kepler-20 system includes three other planets that are larger than Earth but smaller than Neptune. Kepler-20b, the closest planet, Kepler-20c, the third planet, and Kepler-20d, the fifth planet, orbit their star every 3.7, 10.9 and 77.6 days.

All five planets have orbits lying roughly within Mercury’s orbit in our Solar System. The host star belongs to the same G-type class as our Sun, although it is slightly smaller and cooler.

Odd planetary system

The system has an unexpected arrangement. In our Solar System, small, rocky worlds orbit close to the Sun and large, gaseous worlds orbit farther out. In comparison, the planets of Kepler-20 are organised in alternating size: large, small, large, small and large.

“The Kepler data are showing us some planetary systems have arrangements of planets very different from that seen in our Solar System,” said Jack Lissauer, planetary scientist and Kepler science team member at NASA’s Ames Research Centre.

“The analysis of Kepler data continue to reveal new insights about the diversity of planets and planetary systems within our galaxy.”

Scientists are not certain how the system evolved but they do not think the planets formed in their existing locations.

They theorise the planets formed farther from their star and then migrated inward, likely through interactions with the disc of material from which they originated.

This allowed the worlds to maintain their regular spacing despite alternating sizes.

Artist's impression of Kepler-20f

Artist's impression of Kepler-20f, which is about 1.03 times as wide as Earth.

Cosmic game of hide and seek

The Kepler space telescope detects planets and planet candidates by measuring dips in the brightness of more than 150,000 stars to search for planets crossing in front, or transiting, their stars.

The Kepler science team requires at least three transits to verify a signal as a planet.

On December 5 the team announced the discovery of Kepler-22b in the habitable zone of its parent star. It is likely to be too large to have a rocky surface.

While Kepler-20e and Kepler-20f are Earth-size, they are too close to their parent star to have liquid water on the surface.

“In the cosmic game of hide and seek, finding planets with just the right size and just the right temperature seems only a matter of time,” said Natalie Batalha, Kepler deputy science team lead and professor of astronomy and physics at San Jose State University.

“We are on the edge of our seats knowing that Kepler’s most anticipated discoveries are still to come.”

Adapted from information issued by NASA/Ames/JPL-Caltech.

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Stratolaunch – a new way to get into space!

A HIGH-POWER TEAM of space and industry experts has come together to propose a radical new way of getting into orbit. Radical in size, that is, if not in overall concept.

The Stratolaunch project would see a huge carrier aircraft twice the size of a Boeing 747, carry a large rocket slung under its mid-section. The whole “stack” would take off like a normal aircraft and climb to altitude, whereupon the rocket would drop away, ignite its engines and shoot into orbit.

The carrier aircraft will be largest aircraft ever flown.

It’s a scaled up version of the system to be used by Richard Branson’s Virgin Galactic.

The Stratolaunch team is led by four famous individuals, prime among them being entrepreneur Paul Allen, co-founder of Microsoft. There’s also Mike Griffin, former head of NASA; Elon Musk, co-founder of PayPal and founder of the SpaceX rocket company; and Burt Rutan, the famed aeronautical designer who designed and built SpaceShipOne and the Virgin Galactic SpaceShipTwo.

More information: Stratolaunch web site

Story by Jonathan Nally. Graphics courtesy Stratolaunch.

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World’s biggest telescope a step closer

Artist's impression of the European Extremely Large Telescope

Artist's impression of the European Extremely Large Telescope

A TELESCOPE TO DWARF ALL OTHERS is on the road to being fully approved in mid-2012, with much of the funding secured and work commencing on the road that will provide access to the remote site in Chile.

The European Extremely Large Telescope (E-ELT) will be an optical/infrared telescope with a main mirror 39.3 metres wide. Today’s current largest telescopes have mirrors around the 10-metre mark.

The European Southern Observatory’s (ESO) huge, 1.802 billion Euro facilitywill be built at Cerro Armazones in Chile’s high Atacama desert.

Artist's impression of the E-ELT alongside the Sydney Opera House

Artist's impression of the E-ELT alongside the Sydney Opera House, to give an idea of scale.

The initial work approved this week includes preparations for the road that will link to the site, and commencement of work on one on the most challenging parts of the telescope…the M4 mirror, an “adaptive optics” mirror that will help to remove the blurring effect of Earth’s atmosphere.

“The E-ELT is starting to become reality,” says the ESO Director General, Tim de Zeeuw. “However, with a project of this size it is expected that approval of the extra expenditure will take time … preparatory work must start now in order for the project to be ready for a full start of construction in 2012.”

Final approval for the E-ELT project is expected to be granted next year.

This video from last year explains more about the amazing E-ELT and the site at which it will be built:

Story by Jonathan Nally. Images and video courtesy ESO.

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Australia from Space: Part 5

IT’S DIFFICULT TO GET A TRUE PICTURE of the scale of Australia’s Red Centre from the ground, but satellite images help us to comprehend the breadth and beauty of the region. These remarkable images were taken by the Proba, Envisat and Landsat satellites, and show two of Australia’s most famous landmarks—Uluru and Lake Eyre.

Uluru

The rock formation Uluru, also known as Ayers Rock, as seen by the European Proba satellite. Uluru is the world's largest monolith, and a sacred site to Australia's indigenous peoples. It is 3.6 km long and two km wide. The walk around it covers 9.4 km.

Uluru 2

This black and white Proba image gives us a closer view of Uluru, and shows the layers of rock titled towards the vertical.

Lake Eyre Basin

This Envisat image highlights the Lake Eyre Basin, one of the world’s largest internally draining systems, in the heart of Australia. White cloud streaks stand in contrast to the Red Centre’s vast amounts of crimson soil and sparse greenery. The basin covers about 1.2 million sq km (about the size of France, Germany and Italy combined), including large portions of South Australia (bottom), the Northern Territory (upper left) and Queensland (upper right) and a part of western New South Wales (bottom right). This image was acquired by the European Envisat satellite’s Medium Resolution Imaging Spectrometer on 3 July 2010 at a resolution of 300 metre.

Lake Eyre

This Landsat satellite image shows a portion of Lake Eyre (lower-left corner) and the north-south sand dunes of the Simpson and Tirari deserts in the remote outback of South Australia. The Thematic Mapper on Landsat 5 acquired this image on 31 May 2011.

Earlier Australia from Space pictorials:

Australia from Space: Part 1

Australia from Space: Part 2

Australia from Space: Part 3

Australia from Space: Part 4

Adapted from information issued by ESA.

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“Vampire star” devouring its companion

ASTRONOMERS HAVE OBTAINED the best images ever of a star that has lost most of its material to a vampire companion.

By combining the light captured by four telescopes at the European Southern Observatory’s (ESO) Paranal Observatory (Chile), they created a virtual telescope 130 metres across with vision 50 times sharper than the Hubble Space Telescope.

Surprisingly, the new results show that the transfer of gas from one star to the other in this double system is gentler than expected.

The video above shows a “zoom in”, through several different images of different resolution, ending with what looks like two blobs—a blue one and a orangeish one. These are the real images of the two stars, with the red giant being the bigger one. Images taken on different dates show how the stars have moved in their mutual orbit around each other.

The astronomers observed the unusual system SS Leporis in the constellation of Lepus (The Hare), which contains two stars that circle around each other in 260 days.

The stars are very close together…separated by only a little more than the distance between the Sun and the Earth. In terms of size, the larger and cooler of the two stars (a red giant) is big enough to extend out to one quarter of this distance — corresponding roughly to the orbit of Mercury.

Because of this closeness, the hot companion star has already cannibalised about half of the mass of the larger star.

The new observations are sharp enough to show that the giant star is smaller than previously thought, making it much more difficult to explain how it lost matter to its companion.

The astronomers now think that, rather than streaming from one star to the other, the gas must be expelled from the giant star as a stellar wind and then captured by the hotter companion.

Adapted from information issued by ESO / Digitised Sky Survey 2 / Nick Risinger (skysurvey.org) / PIONIER / IPAG; music: John Dyson (from the album Moonwind).

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Get ready for the total lunar eclipse!

Total lunar eclipse

We'll all get to see a total eclipse of the Moon on the night of December 10/11, 2011.

  • Total lunar eclipse, Saturday, December 10
  • Visible from all over Australia and New Zealand
  • Easy to see — you don’t need a telescope

SKYWATCHERS in Australia and New Zealand will be treated to a total eclipse of the Moon, late in the evening on December 10 and into December 11.

An eclipse of the Moon happens when the Moon moves into the Earth’s shadow. If the Moon goes through the middle of the shadow, it is a total lunar eclipse. (If it “cuts the corner” of the shadow, we get a partial eclipse.)

There are usually 2-3 lunar eclipses each year, but they’re not always visible from the same place. From any particular spot on Earth, you might see 1 or 2 per year.

December 10 lunar eclipse

There are two parts to the Earth’s shadow—the outer, dim penumbra; and the inner, darker, umbra. When the Moon moves into the penumbra it is, technically, in eclipse, but it is very hard to see any darkening of the lunar surface. Some eclipses occur only in the penumbra, and the darkening is so slight that most people wouldn’t even know it was happening.

For this eclipse, the Moon will start to move into the umbra at 11:46pm, Australian Eastern Daylight Time (AEDT) on Saturday, December 10. That’s 8:46pm in Perth, 11:16pm in Adelaide and 9:46pm in Darwin.

This won’t be a very long event compared to others that we’ve seen recently. The Moon will be fully eclipsed for only 51 minutes (but there are the partial phases before and after).

But unlike some eclipses where particular areas miss out on seeing the start or finish, everyone will be able to see the whole thing from end to end (weather permitting of course).

Mid-eclipse will occur at 01:32am AEDT, and the whole thing will be over by 3:18am AEDT on Sunday morning. (Adjust for your own time zone.)

Diagram of eclipse

The stages of the eclipse. U1 is where the Moon starts to move into the darkest part of Earth's shadow (the umbra) and where the first "bite" appears to be taken out of the lunar disc. U2 is where the Moon is fully inside the shadow and is therefore totally eclipsed. U3 is where the Moon begins to move out of the umbra, and U4 is where it is fully out of the umbra.

When and where to see it

The Moon will be in the northern part of the sky. As long as the weather is clear, you won’t have any difficulty seeing the eclipse.

You won’t need a telescope or binoculars – just your own eyes are enough to take in the view.

And it’s good to remember that eclipses happen fairly slowly, so if you don’t fancy staying out to watch the whole thing, just go outside every 10-15 minutes or so and see how it has changed.

And of course, unlike solar eclipses, lunar eclipses are perfectly safe to watch.

Eclipses in 2012

Next year will be a thin one for eclipses for Aussies — there’ll be one, pretty average partial lunar eclipse, but we’ll get a fantastic total eclipse of the Sun.

The partial lunar eclipse will occur on June 4, 2012, and will be visible from eastern and central Australia.

The total eclipse of the Sun will occur on the morning of Nov 14, 2012—and it will be the last one to be seen in Australia until the year 2028! Totality will be seen only along a narrow swathe of far north Queensland near Cairns. Everyone else will see a partial eclipse.

Here are some more web resources for the December 10 total lunar eclipse:

Melbourne Planetarium’s Skynotes site

IceInSpace guide to the eclipse

Royal Astronomical Society of New Zealand guide to the eclipse

Wikipedia page on the eclipse

Story by Jonathan Nally. Many thanks to Tanya Hill, astronomer at the Melbourne Planetarium, for spotting an error in the original timings given above; now corrected.

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