A so-called gravitational lens is produced when space is warped by a massive foreground object, whether it is the sun, a black hole or an entire cluster of galaxies. The light from more-distant background objects is distorted, brightened and magnified as it passes through this gravitationally disturbed region.

A team of astronomers led by Jane Rigby of NASA's Goddard Space Flight Center in Greenbelt, Md., aimed Hubble at one of the most striking examples of gravitational lensing, a nearly 90-degree arc of light in the galaxy cluster RCS2 032727-132623. Hubble's view of the distant background galaxy is significantly more detailed than could ever be achieved without the help of the gravitational lens.

The results have been accepted for publication in the Astrophysical Journal, in a paper led by Keren Sharon of the Kavli Institute for Cosmological Physics at the University of Chicago. Professor Michael Gladders and graduate student Eva Wuyts of the University of Chicago were also key team members.

The presence of the lens helps show how galaxies evolved from 10 billion years ago to today. While nearby galaxies are fully mature and are at the tail end of their star-formation histories, distant galaxies tell us about the universe's formative years.

The light from those early events is just now arriving at Earth. Very distant galaxies are not only faint but also appear small on the sky. Astronomers would like to see how star formation progressed deep within these galaxies. Such details would be beyond the reach of Hubble's vision were it not for the magnification made possible by gravity in the intervening lens region.

In 2006 a team of astronomers using the Very Large Telescope in Chile measured the arc's distance and calculated that the galaxy appears more than three times brighter than previously discovered lensed galaxies. In 2011 astronomers used Hubble to image and analyze the lensed galaxy with the observatory's Wide Field Camera 3.

The distorted image of the galaxy is repeated several times in the foreground lensing cluster, as is typical of gravitational lenses. The challenge for astronomers was to reconstruct what the galaxy really looked like, were it not distorted by the cluster's funhouse-mirror effect.

Hubble's sharp vision allowed astronomers to remove the distortions and reconstruct the galaxy image as it would normally look. The reconstruction revealed regions of star formation glowing like bright Christmas tree bulbs. These are much brighter than any star-formation region in our Milky Way galaxy.

Through spectroscopy, the spreading out of the light into its constituent colors, the team plans to analyze these star-forming regions from the inside out to better understand why they are forming so many stars.

]]> Wed, 08 FEB 2012 08:47:33 AEST Pasadena CA (JPL) Jan 31, 2012 - NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, mission arrived at Vandenberg Air Force Base in California this morning after a cross-country trip by truck from the Orbital Sciences Corporation's manufacturing plant in Dulles, Va.

The mission is scheduled to launch from Kwajalein Atoll in the Pacific Ocean on March 14.

Once the observatory is offloaded at Vandenberg, it will be moved into a processing hangar, joining the Pegasus XL rocket that is set to carry it to space. Over the weekend, technicians will remove its shipping container so that checkout and other processing activities can begin next week.

Once the observatory is integrated with the rocket in mid-February, technicians will encapsulate it in the vehicle fairing, which is also scheduled to arrive at Vandenberg.

After processing is completed, the rocket and spacecraft will be flown on Orbital's L-1011 carrier aircraft to the Ronald Reagan Ballistic Missile Defense Test Site at Kwajalein Atoll for launch in March.

NuSTAR is a small-explorer mission managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate in Washington The spacecraft was built by Orbital Sciences Corporation.

Its instrument was built by a consortium including the California Institute of Technology, Pasadena; JPL; Columbia University, New York, N.Y.; NASA's Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; the University of California, Berkeley; and ATK, Goleta, Calif.

NuSTAR will be operated by UC Berkeley, with the Italian Space Agency providing its equatorial ground station located at Malindi, Kenya. The mission's outreach program is based at Sonoma State University, Calif. NASA's Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

]]> Wed, 08 FEB 2012 08:47:33 AEST Baltimore MD (SPX) Jan 16, 2012 - Using NASA's Hubble Space Telescope, astronomers have solved a longstanding mystery on the type of star, or so-called progenitor, which caused a supernova seen in a nearby galaxy. The finding yields new observational data for pinpointing one of several scenarios that trigger such outbursts.

Based on previous observations from ground-based telescopes, astronomers knew the supernova class, called a Type Ia, created a remnant named SNR 0509-67.5, which lies 170,000 light-years away in the Large Magellanic Cloud galaxy.

Theoretically, this kind of supernova explosion is caused by a star spilling material onto a white dwarf companion, the compact remnant of a normal star, until it sets off one of the most powerful explosions in the universe.

Astronomers failed to find any remnant of the companion star, however, and concluded that the common scenario did not apply in this case, although it is still a viable theory for other Type Ia supernovae.

"We know Hubble has the sensitivity necessary to detect the faintest white dwarf remnants that could have caused such explosions," said lead investigator Bradley Schaefer of Louisiana State University (LSU) in Baton Rouge. "The logic here is the same as the famous quote from Sherlock Holmes: 'when you have eliminated the impossible, whatever remains, however improbable, must be the truth.'"

The cause of SNR 0509-67.5 can be explained best by two tightly orbiting white dwarf stars spiraling closer and closer until they collided and exploded.

For four decades, the search for Type Ia supernovae progenitors has been a key question in astrophysics. The problem has taken on special importance during the last decade with Type Ia supernovae being the premier tools for measuring the accelerating universe.

Type Ia supernovae release tremendous energy, in which the light produced is often brighter than an entire galaxy of stars. The problem has been to identify the type of star system that pushes the white dwarf's mass over the edge and triggers this type of explosion. Many possibilities have been suggested, but most require that a companion star near the exploding white dwarf be left behind after the explosion.

Therefore, a possible way to distinguish between the various progenitor models has been to look deep in the center of an old supernova remnant to search for the ex-companion star.

In 2010, Schaefer and Ashley Pagnotta of LSU were preparing a proposal to look for any faint ex-companion stars in the center of four supernova remnants in the Large Magellanic Cloud when they discovered the Hubble Space Telescope already had taken the desired image of one of their target remnants, SNR 0509-67.5, for the Hubble Heritage program, which collects images of especially photogenic astronomical targets.

In analyzing the central region, they found it to be completely empty of stars down to the limit of the faintest objects Hubble can detect in the photos. Schaefer suggests the best explanation left is the so-called "double degenerate model" in which two white dwarfs collide.

The results are being reported at the meeting of the American Astronomical Society in Austin, Texas. A paper on the results will be published in the the journal Nature.

There are no recorded observations of the star exploding. However, researchers at the Space Telescope Science Institute in Baltimore, Md. have identified light from the supernova that was reflected off of interstellar dust, delaying its arrival at Earth by 400 years. This delay, called a light echo of the supernova explosion also allowed the astronomers to measure the spectral signature of the light from the explosion. By virtue of the color signature, astronomers were able to deduce it was a Type Ia supernova.

Because the remnant appears as a nice symmetric shell or bubble, the geometric center can be determined accurately. These properties make SNR 0509-67.5 an ideal target to search for ex-companions. The young age also means that any surviving stars have not moved far from the site of the explosion.

The team plans to look at other supernova remnants in the Large Magellenic Cloud to further test their observations.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

]]> Wed, 08 FEB 2012 08:47:33 AEST Austin TX (SPX) Jan 13, 2012 - NASA's Hubble Space Telescope has looked deep into the distant universe and detected the feeble glow from a star that exploded more than 9 billion years ago.

This isn't just any dying star. It belongs to a special class called Type Ia supernovae, which are bright beacons used as distance markers for studying the expansion rate of the universe. Type Ia supernovae most likely arise when white dwarf stars - the burned-out cores of normal stars - siphon too much material from their companion stars and explode.

The stellar explosion, given the nickname SN Primo, will help astronomers place better constraints on the nature of dark energy - a mysterious repulsive force that is causing the universe to fly apart ever faster.

SN Primo is the farthest Type Ia supernova whose distance has been confirmed through spectroscopic observations. Spectroscopy is the "gold standard" for measuring supernova distances.

A spectrum splits the light from a supernova into its constituent colors. By analyzing those colors, astronomers can confirm its distance by measuring how much the supernova's light has been stretched, or reddened, into near-infrared wavelengths due to the expansion of the universe.

The sighting is the first result from a three-year Hubble program to survey faraway Type Ia supernovae, opening a new distance realm for searching for this special class of stellar explosion. The remote supernovae will help astronomers determine whether the exploding stars remain dependable cosmic yardsticks across vast distances of space in an epoch when the cosmos was only one-third its current age of 13.7 billion years.

Called the CANDELS+CLASH Supernova Project, the census is using the sharpness and versatility of Hubble's Wide Field Camera 3 (WFC3) to help astronomers search for supernovae in near-infrared light and verify their distance with spectroscopy.

WFC3 is looking in regions targeted by two large Hubble programs called the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and the Cluster Lensing and Supernova Survey with Hubble (CLASH).

"In our search for supernovae, we had gone as far as we could go in optical light," said the project's lead investigator, Adam Riess of the Space Telescope Science Institute and The Johns Hopkins University in Baltimore, Md.

"But it's only the beginning of what we can do in infrared light. This discovery demonstrates that we can use the Wide Field Camera 3 to search for supernovae in the distant universe."

The new results are being presented at the American Astronomical Society meeting in Austin, Texas. A paper describing the study has been accepted for publication in The Astrophysical Journal.

The supernova team's search technique involved taking multiple near-infrared images over several months, looking for a supernova's faint glow.

Once the team spotted the stellar blast in October 2010, they used WFC3's spectrograph to verify SN Primo's distance and to decode its light, finding the unique signature of a Type Ia supernova. The team then re- imaged SN Primo periodically for eight months, measuring the slow dimming of its light.

By taking the census, the astronomers hope to determine the frequency of Type Ia supernovae during the early universe and glean insights into the mechanisms that detonated them.

"If we look into the early universe and measure a drop in the number of supernovae, then it could be that it takes a long time to make a Type Ia supernova," said Steve Rodney of The Johns Hopkins University, the science paper's first author.

"Like corn kernels in a pan waiting for the oil to heat up, the stars haven't had enough time at that epoch to evolve to the point of explosion. However, if supernovae form very quickly, like microwave popcorn, then they will be immediately visible, and we'll find many of them, even when the universe was very young. But each supernova is unique. It's possible that there are multiple ways to make a supernova."

If astronomers discover that Type Ia supernovae begin to depart from how they expect them to look, they might be able to gauge those changes and make the measurements of dark energy more precise, Riess explained. Riess and two other astronomers shared the 2011 Nobel Prize in Physics for discovering dark energy 13 years ago, using Type Ia supernovae to plot the universe's expansion rate.

After extending the frontier for supernova discoveries with Hubble, a full scrutiny of this new territory will have to wait for the James Webb Space Telescope (JWST). Scheduled to launch later this decade, JWST will probe exploding stars at much farther distances than Hubble can reach.

JWST will be able to see farther into the infrared than Hubble does. This capability will push back the frontier by probing more than 11 billion years back in time, when the universe was only 2 billion years old.

]]> Wed, 08 FEB 2012 08:47:33 AEST Tempe AZ (SPX) Jan 11, 2012 - On January 14, 2012, the second 8.4-meter (27.6 ft) diameter mirror for the Giant Magellan Telescope (GMT) will be cast inside a rotating furnace at the UA's Steward Observatory Mirror Lab underneath the campus football stadium. The Mirror Lab will host a special event to highlight this milestone in the creation of the optics for the Giant Magellan Telescope.

The GMT features an innovative design utilizing seven mirrors, each 8.4 meters in diameter, arranged as segments of a single mirror 24.5 meters (80 feet) in diameter, to bring starlight to a common focus via a set of adaptive secondary mirrors configured in a similar seven-fold pattern.

"In this design the outer six mirrors are off-axis paraboloids and represent the greatest optics challenge ever undertaken in astronomical optics by a large factor" said Roger Angel, Director of the Steward Observatory Mirror Lab (SOML).

The GMT will allow astronomers to answer some of the most pressing questions about the cosmos including the detection, imaging, and characterization of planets orbiting other stars, the nature of dark matter and dark energy, the physics of black holes, and how stars and galaxies evolved during the earliest phases of the universe.

"Astronomical discovery has always been paced by the power of available telescopes and imaging technology. The GMT allows another major step forward in both sensitivity and image sharpness" said Peter Strittmatter, Director of Steward Observatory.

"In fact the GMT will be able to acquire images 10 times sharper than the Hubble Space Telescope and will provide a powerful complement not only to NASA's 6.5-meter James Webb Space Telescope (JWST) but also to the Atacama Large Millimeter Array (ALMA) and the Large Synoptic Survey Telescope (LSST), both located in the southern hemisphere."

Patrick McCarthy, GMT Project Director, added "This second GMT casting is going forward now because the primary optics are on the critical path for the project and because the polishing of the first off-axis 8.4-meter GMT mirror is very close to completion, with an optical surface accuracy within about 25 nanometers, or about one-thousandth the thickness of a human hair."

Like other mirrors produced by the SOML, the GMT mirrors are designed to be spun cast, thereby achieving the basic front surface in the shape of a paraboloid. A paraboloid is the shape taken on by water in a bucket when the bucket is spun around its axis; the water rises up the walls of the bucket while a depression forms in the center.

Some 21 tons of borosilicate glass, made by the Ohara Corporation, flow into a pre-assembled mold to create a lightweight honeycomb glass structure that is very stiff and quickly adjusts to changes in nighttime air temperature, each resulting in sharper images.

The Mirror Lab has already produced the world's four largest astronomical mirrors, each 8.4 meters in diameter.

Two are in operation in the Large Binocular Telescope (LBT) - currently the largest telescope in the world, one is for the Large Synoptic Survey Telescope (LSST), and the fourth is the first off-axis mirror for GMT. The Mirror Lab has also produced five 6.5-meter mirrors, two of which are in the twin Magellan telescopes at Las Campanas Observatory in Chile.

"The novel technology developed at the Mirror Lab is creating a whole new generation of large telescopes with unsurpassed image sharpness and light collecting power," said Wendy Freedman, Director of the Carnegie Observatories and Chair of the GMTO Board. "The SOML mirrors in the twin Magellan Telescopes at our Las Campanas Observatory site are performing superbly and led to our adoption of this technology for the GMT."

The GMT is set to begin science operations in 2020 at the Las Campanas Observatory, exploiting the clear dark skies of the Atacama Desert in northern Chile.

"With funding commitments in hand for close to half of the $700 million required to complete the project, with one mirror essentially finished and the second about to be cast, and with the planned groundbreaking at Las Campanas in February of this year, the project is on track to meet this schedule goal," said Matthew Colless, Director of the Australian Astronomical Observatory.

"The giant mirrors being spun cast for the GMT at the Steward Observatory Mirror Lab are like the sails of the great ships of exploration ca. 1500, except here the discoveries are not lands across the ocean, but rather the nature of whole new worlds and island universes, spanning all of space and time," said Joaquin Ruiz, Dean of the College of Science, University of Arizona.

"We at Arizona are proud to participate in such an exciting international scientific project as the GMT."

]]> Wed, 08 FEB 2012 08:47:33 AEST Munich, Germany (SPX) Jan 10, 2012 - On 1 January 2012, European radio astronomy entered a new era with the implementation of RadioNet3, the third iteration of RadioNet, the European radio astronomy collaboration.

As the recognised European body for radio astronomy, RadioNet aims at facilitating access to leading radio astronomy facilities around the world for European radio astronomers.

The European Commission recently secured the project by granting it 9.5 million euros for the period 2012-2015. The Max-Planck Institute for Radio Astronomy (MPIfR) will work with 24 European partner institutions, as well as South Korea, Australia and South Africa, to offer access to all 18 existing radio astronomy facilities in Europe.

The project will also take full advantage of the APEX telescope operated by ESO, as well as the recently opened Atacama Large Millimeter/submillimeter Array (ALMA) of which ESO is a partner, both located in Chile.

By promoting cooperation and making use of state-of-the-art facilities around the world, RadioNet3 will thus ensure European radio facilities remain competitive, and prepare European scientists and engineers for the upcoming Square Kilometre Array (SKA), scheduled to start early operations in 2019.

]]> Wed, 08 FEB 2012 08:47:33 AEST Paris, France (SPX) Jan 06, 2012 - RadioNet3, a four-year, 9.5M euro project offering unprecedented access to 18 state-of-the-art European radio telescopes, including the ALMA (Atacama Large Millimeter Array) in Chile and the James Clerk Maxwell Telescope in Hawaii, has been launched.

The project, in which the Science and Technology Facilities Council (STFC) is playing a key role, will ensure that European radio astronomy facilities remain globally competitive by increasing expertise in the research community and developing new instruments for current and proposed telescopes such as the Square Kilometer Array.

The funding from the European Commission builds on the success of previous radio astronomy projects, RadioNet1 and 2. RadioNet3 began on New Years' Day and is a collaboration of 27 world class European organizations including STFC.

Led by the Max Planck Institute for Radio Astronomy (MPIfR), it is combining the best equipment available with the top radio astronomical expertise to ultimately improve our knowledge of our Universe.

The new program will stimulate new activities in research and development of both the existing radio infrastructures as well as telescopes of the future, including the largest radio telescope in the world - the Square Kilometer Array (SKA) - due to be completed within the next decade.

Prof. Gary Davis, Director of STFC's Joint Astronomy Centre in Hawaii and STFC's representative on the RadioNet3 Board, said: "The outcomes of RadioNet3 will be fundamental in the development of telescopes such as SKA, both in terms of instruments and expertise. STFC will be contributing its world-leading expertise in developing technologies for a new generation of astronomical radio receivers."

The networking activities of RadioNet3 will provide a natural forum for developing further European collaborations, sharing both ideas and results, and engaging researchers. This is particularly important with the emergence of new research opportunities through SKA.

"Our aim is to establish a long-term strategy for structuring radio astronomy in Europe", says Prof. Anton Zensus, Director at MPIfR and coordinator of the RadioNet3 project.

"We will make sure the results are available to the outside world, and that the next generation of scientists and engineers are prepared for the advent of the new generation radio telescopes."

]]> Wed, 08 FEB 2012 08:47:33 AEST Hutsville AL (SPX) Jan 10, 2012 - The James Webb Space Telescope marked a year of significant progress in 2011 as it continues to come together as NASA's next generation space telescope. The year brought forth a pathfinder backplane to support the large primary mirror structure, mirror cryotesting, creation of mirror support structures, several successful sunshield layer tests and the creation of an assembly station within NASA Goddard Space Flight Center's cleanroom.

Achievements were also made in the areas of flight and communications software and the propulsion system.

In December, manufacturing and testing of all flight mirrors was completed in a final test at the X-ray and Calibration Facility at Marshall Space Flight Center, Huntsville, Ala. During these tests mirror segments were chilled to temperatures similar to those Webb will see in space, around minus 400 degrees Fahrenheit.

It was the culmination of work started in 2003. Heeding lessons learned from the Hubble Space Telescope, the program adopted the strategy of tackling the most difficult technical challenges first. That decision proved to be the right one. In June, all 18 flight primary mirror segments, plus the secondary, tertiary and fine steering mirrors, were polished and coated yielding exquisite surfaces that will enable Webb to image the most distant galaxies.

Two of Webb's supporting and pathfinder structures were also completed. To assemble the flight telescope on the ground, a 139,000 pound structure will install the flight mirrors using an overhead track system supporting a robotic arm. The huge platform has been completed and assembled in the ultra-clean room used for telescope assembly at Goddard.

Also finished was the pathfinder backplane, a full-scale engineering model of the center section of the flight backplane. The backplane holds the mirror segments in place to form a single primary mirror.

The full pathfinder element will consist of 12 of the 18 hexagonal cells (the center section of the primary mirror) of the telescope and contain a subset of two primary mirror segment assemblies, the secondary mirror, and the subsystem containing the tertiary and fine steering mirrors. It will demonstrate integration and test procedures that will be used on the flight telescope.

Webb's giant sunshield moved forward into a new testing phase last year, the final step before fabrication of the flight sunshield. Sunshield layer three became the first of five full-size flight-like layers stretched out in a fully simulated flight configuration.

This enables engineers to make 3-D shape measurements that will tell them how the full-size sunshield layers will behave in space. Completing this test is a critical step in the sunshield's development and gives the engineers confidence and experience needed to manufacture the five flight layers.

An important sunshield deployment flight structure also completed fabrication in 2011. The space-qualified graphite composite tubes that will enable the sunshield to deploy in space have finished fabrication. The telescoping tube system was designed at Astro Aerospace, a business unit of Northrop Grumman.

Capping the year's achievements, Webb's spacecraft also moved forward. The propulsion system's 16 monopropellant rocket engine thrusters, which control momentum and station-keeping on orbit, were upgraded to accept higher heat loading from the sunshield.

Propulsion engineers also completed building four flight secondary combustion augmented thrusters which maintain orbit after the launch vehicle finishes its burns. Engineers also verified the flight software responsible for ground commands and science data delivery.

Successor to the Hubble Space Telescope, the James Webb Space Telescope is the world's next-generation space observatory. It is the most powerful space telescope ever built.

Webb will observe the most distant objects in the universe, provide images of the very first galaxies ever formed and study planets around distant stars. The Webb Telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.

]]> Wed, 08 FEB 2012 08:47:33 AEST La Serena, Chile (SPX) Jan 06, 2012 - On December 16, 2011, a decade of hard work culminated at the Gemini South telescope in Chile, when a next-generation adaptive optics (AO) system produced its first ultra-sharp wide field image. The first target image showed a portion of a dense cluster of stars called NGC 288. This first light image reveals details at nearly the theoretical limit of Gemini's large 8-meter mirror over an unprecedented large patch of the night sky.

The crispness of the first-light image clearly demonstrates the potential of the system, which is poised to provide astronomers with a powerful new tool for the study of a wide range of phenomena: from black holes at the centers of galaxies to the life histories of stars.

Called the Gemini Multi-conjugate adaptive optics System (GeMS for short), it uses five artificial guide stars made by a laser to provide extreme clarity over the largest area of night sky ever captured in a single AO observation - an area of the night sky which is 10 times larger than that covered by any other existing AO system in the world.

The reaction to this achievement has been swift and positive. When Space Telescope Science Institute director Matt Mountain saw the first light image, he praised the GeMS instrument team: "Incredible! You have truly revolutionized ground-based astronomy!"

Mountain was the director of the Gemini Observatory when the GeMS project began a decade ago. He also put together the original team, selecting Francois Rigaut as the lead scientist to develop the GeMS instrument.

Rigaut was in the Observatory's control room high in the Chilean Andes when the new infrared image first appeared on the viewing monitor.

"We couldn't believe our eyes!" Rigaut recalls. "The image of NGC 288 revealed thousands of pinpoint stars. Its resolution is Hubble-quality - and from the ground this is phenomenal."

Rigaut explained that with the new gain in angular resolution the crowded city of stars captured in the first light image appears no more densely populated than a typical field in the Milky Way. "This is somewhat uncharted territory: no one has ever made images so large with such a high angular resolution."

University of Toronto astronomer Roberto Abraham, one of a community of hundreds of astronomers worldwide who uses the 8-meter Gemini telescopes for cutting-edge research, was less reserved: "This is fan-freaking-tastic!!!!!!!" he wrote.

The first-light observing run culminated a decade-long effort in instrument planning and development. "We were lucky to have clear weather and stable atmospheric conditions that night," said Gemini AO scientist Benoit Neichel. "Even despite interruptions of the laser propagation due to satellites and planes passing by, we obtained our first image with the system. It was surprisingly crisp and large, with an exquisitely uniform image quality."

Gemini's new system overcomes two limitations that have plagued the previous generation of AO systems: (1) a limited number of stars bright enough to guide on; and (2) a small field-of-view (the size of the patch of sky observed in a single observation).

While not a new solution, lasers have proved to be an effective solution to the first problem. When no "natural" guide star is available, an artificial one is created using a powerful laser emitting the well-known orange color used in some streetlights. This laser guide star technology is currently being used by observatories around the world, including both Gemini telescopes in Chile and Hawai'i.

Gemini solved the field-of-view problem with a technique called Multi-Conjugate Adaptive Optics (MCAO). By using five laser guide stars (rather than a single one as in other systems), tomographic atmospheric modeling techniques borrowed from medical imaging, and several deformable mirrors, MCAO extends the field-of-view of AO systems by 10 times or more; it also produces images with exquisitely uniform image quality across the entire field-of-view. GeMS is the first of its kind to combine laser guide stars with MCAO, which opens up more of the nighttime sky for detailed study.

"MCAO is game-changing," Abraham said. "It's going to propel Gemini to the next echelon of discovery space as well as lay a foundation for the next generation of extremely large telescopes. Gemini is going to be delivering amazing science while paving the way for the future."

GeMS development started at Gemini in the early 2000s. The system was assembled in the Gemini instrumentation laboratories over the past four years and uses an infrared imager called the Gemini South AO Imager (GSAOI) built at the Australian National University. The GeMS team field-tested it on the telescope during several commissioning periods in 2011, and performed the final tests in mid-December.

GeMS work will continue through the first half of 2012. Testing will focus on stability, performance optimization, and integration into operations. It will gradually be opened to the Gemini astronomy community during 2012.

Background on Adaptive Optics: Taking the Twinkle Out of Starlight
Why adaptive optics? It's the answer to some of the problems created by Earth's atmosphere that have plagued astronomers for centuries. The atmosphere has two detrimental effects for astronomical observations. First, it filters out some incoming ultraviolet and part of the infrared spectrum. Second, warm and cold air mixing together create atmospheric turbulence, which causes starlight to twinkle and ground-based telescopic images to blur: a phenomenon called "seeing." In good seeing, the atmosphere does not distort starlight as much as it does in bad seeing.

To surmount these two problems, some scientists have sent telescopes into orbit, an idea first suggested by German rocket scientist Hermann Oberth in the early 1920s. Although very successful, these endeavors are also very expensive.

In the 1950s, however, astronomer Horace Babcock (Mt. Wilson Observatory) derived an idea for solving the second problem. He imagined improving "seeing" by compensating for atmospheric distortions with special optics.

The first prototypes for astronomy of his novel idea were built in the 1980s and came to be known as adaptive optics (AO). The method uses a combination of light-wave sensors and deformable mirrors. AO un-poetically removes the twinkle from the star's light and restores the ultimate angular resolution limit from a telescope's optics. The end result is as if the atmospheric turbulence didn't exist. By using AO on the current generation of large telescopes, this typically means being able to see a hundred times more detail in images of planets, stars, nebulae, or galaxies.

]]> Wed, 08 FEB 2012 08:47:33 AEST Greenbelt MD (SPX) Dec 27, 2011 - Cryogenic testing is complete for the final six primary mirror segments and a secondary mirror that will fly on NASA's James Webb Space Telescope. The milestone represents the successful culmination of a process that took years and broke new ground in manufacturing and testing large mirrors.

"The mirror completion means we can build a large, deployable telescope for space," said Scott Willoughby, vice president and Webb program manager at Northrop Grumman Aerospace Systems. "We have proven real hardware will perform to the requirements of the mission."

The Webb telescope has 21 mirrors, with 18 mirror segments working together as a large 21.3-foot (6.5-meter) primary mirror. Each individual mirror segment now has been successfully tested to operate at 40 Kelvin (-387 Fahrenheit or -233 Celsius).

"Mirrors need to be cold so their own heat does not drown out the very faint infrared images," said Lee Feinberg, NASA Optical Telescope Element manager for the Webb telescope at the agency's Goddard Space Flight Center in Greenbelt, Md.

"With the completion of all mirror cryogenic testing, the toughest challenge since the beginning of the program is now completely behind us."

Completed at the X-ray and Cryogenic Facility (XRCF) at NASA's Marshall Space Flight Center in Huntsville, Ala., a ten-week test series chilled the primary mirror segments to -379 degrees Fahrenheit.

During two test cycles, telescope engineers took extremely detailed measurements of how each individual mirror's shape changed as it cooled.

Testing verified each mirror changed shape with temperature as expected and each one will be the correct shape upon reaching the extremely cold operating temperature after reaching deep space.

"Achieving the best performance requires conditioning and testing the mirrors in the XRCF at temperatures just as cold as will be encountered in space," said Helen Cole, project manager for Webb Telescope mirror activities at the XRCF.

"This testing ensures the mirrors will focus crisply in space, which will allow us to see new wonders in our universe."

Ball Aerospace and Technologies Corp. in Boulder, Colo. successfully completed comparable testing on the secondary mirror.

However, because the secondary mirror is convex (i.e., it has a domed surface that bulges outward instead of a concave one that dishes inward like a bowl), it does not converge light to a focus. Testing the mirror presented a unique challenge involving a special process and more complex optical measurements.

A video accompanying this release is available here.

]]> Wed, 08 FEB 2012 08:47:33 AEST Subscribe to our daily selection of space, military, environment and energy newsletters responseText http://visitor.constantcontact.com/manage/optin/ea?v=0016gbbKsaiGSpQFojVO8ZoHw%3D%3D