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Scientists invent world’s fastest and most sensitive astronomical camera

June 20, 2009 By admin Leave a Comment

Munich, June 19 (ANI): Scientists have invented the world’s fastest and most sensitive astronomical camera that can take 1500 finely exposed images per second even when observing extremely faint objects.

The first 240×240 pixel images with the world’s fastest high precision faint light camera were obtained through a collaborative effort between ESO and three French laboratories from the French Centre National de la Recherche Scientifique/Institut National des Sciences de l’Univers (CNRS/INSU).

Cameras such as this are key components of the next generation of adaptive optics instruments of Europe’s ground-based astronomy flagship facility, the ESO Very Large Telescope (VLT).

“The performance of this breakthrough camera is without an equivalent anywhere in the world. The camera will enable great leaps forward in many areas of the study of the Universe,” said Norbert Hubin, head of the Adaptive Optics department at ESO.

OCam will be part of the second-generation VLT instrument SPHERE. To be installed in 2011, SPHERE will take images of giant exoplanets orbiting nearby stars.

A fast camera such as this is needed as an essential component for the modern adaptive optics instruments used on the largest ground-based telescopes.

Telescopes on the ground suffer from the blurring effect induced by atmospheric turbulence.

This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it blurs the finest details of the images.

Adaptive optics techniques overcome this major drawback, so that ground-based telescopes can produce images that are as sharp as if taken from space.

The new generation instruments require these corrections to be done at an even higher rate, more than one thousand times a second, and this is where OCam is essential.

Cameras normally used for very high frame-rate movies require extremely powerful illumination, which is of course not an option for astronomical cameras.

OCam and its CCD220 detector, developed by the British manufacturer e2v technologies, solve this dilemma, by being not only the fastest available, but also very sensitive, making a significant jump in performance for such cameras.

Because of imperfect operation of any physical electronic devices, a CCD camera suffers from so-called readout noise.

OCam has a readout noise ten times smaller than the detectors currently used on the VLT, making it much more sensitive and able to take pictures of the faintest of sources. (ANI)

Use the net to go ‘around the world in 80 telescopes’

April 3, 2009 By admin Leave a Comment

London, April 3 (ANI): In a live 24-hour webcast today, anyone on the Internet will get a unique opportunity to explore some of the most advanced astronomical observatories both on and off the planet, as part of the International Year of Astronomy (IYA2009) initiative ‘Around the World in 80 Telescopes’.

The webcast would start with a broadcast from the Gemini North Telescope in Hawaii at 10am BST, night time in Hawaii, moving around the globe for whistle-stop tours of the international observatories, while the large telescopes are exploring night skies, observing distant galaxies, searching for extrasolar planets around other stars, or studying our own solar system.

It starts off at the Mauna Kea peak in Hawaii, one of the best places in the world for observatories thanks to the altitude and clear air conditions and the home of UK participating telescopes like the United Kingdom Infra-Red Telescope (UKIRT) and the James Clerk Maxwell Telescope (JCMT).

The telescopes include gravitational-wave detectors such as GEO600 which search for ripples in space-time, space-borne telescopes like SWIFT, STEREO and XMM-NEWTON, and ground-based telescopes such as the Very Large Telescope VLT at the European Southern Observatory’s site in Chile, plus the Jodrell Bank radio telescope in Cheshire.

According to Robin Clegg, Head of Science in Society at STFC (Science and Technology Facilities Council), said, “Exciting astronomical discoveries and indeed the range of telescopes in use are inspirational and stimulate young people to get engaged with science and technology subjects at school,” Clegg added.

As the Earth turns on its axis and the sun rises on Hawaii, the webcast moves around the world, visiting the Anglo-Australian Telescope at 1pm BST, Jodrell Bank Observatory near Manchester at 6pm BST, the William Herschel Telescope in the Canary Islands at 12.10am BST (Saturday morning), finishing up at the Palomar Observatory in California at 09.40am BST, along with dozens of other observatories in between.

“As thousands of local events are being held around the country to celebrate the 400 years since Galileo made his first revolutionary observations and sketches of the Moon, Around the World in 80 Telescopes gives everyone the chance to see the amazing work that professional astronomers do, furthering the boundaries of our knowledge and helping us understand our place in the Universe,” said Steve Owens, UK coordinator for IYA 2009.

Around the World in 80 Telescopes is happening as part of the IYA 2009′s 100 Hours of Astronomy project, which runs from 2-5 April. (ANI)

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Pluto’s lower atmosphere revealed by scientists

March 4, 2009 By admin Leave a Comment

Munich, March 3 (ANI): Astronomers have used the European Southern Observatory’s (ESO’s) Very Large Telescope (VLT) to gain valuable new insights about the lower atmosphere of the dwarf planet Pluto.

The scientists found unexpectedly large amounts of methane in the atmosphere, and also discovered that the atmosphere is hotter than the surface by about 40 degrees, although it still only reaches a frigid minus 180 degrees Celsius.

These properties of Pluto’s atmosphere may be due to the presence of pure methane patches or of a methane-rich layer covering the dwarf planet’s surface.

“With lots of methane in the atmosphere, it becomes clear why Pluto’s atmosphere is so warm,” said Emmanuel Lellouch, lead author of the paper reporting the results.

Pluto, which is about a fifth the size of Earth, is composed primarily of rock and ice. As it is about 40 times further from the Sun than the Earth on average, it is a very cold world with a surface temperature of about minus 220 degrees Celsius.

It has been known since the 1980s that Pluto also has a tenuous atmosphere, which consists of a thin envelope of mostly nitrogen, with traces of methane and probably carbon monoxide.

As Pluto moves away from the Sun, during its 248 year-long orbit, its atmosphere gradually freezes and falls to the ground.

In periods when it is closer to the Sun – as it is now – the temperature of Pluto’s solid surface increases, causing the ice to sublimate into gas.

Until recently, only the upper parts of the atmosphere of Pluto could be studied.

By observing stellar occultations, a phenomenon that occurs when a Solar System body blocks the light from a background star, astronomers were able to demonstrate that Pluto’s upper atmosphere was some 50 degrees warmer than the surface, or minus 170 degrees Celsius.

These observations couldn’t shed any light on the atmospheric temperature and pressure near Pluto’s surface.

But unique, new observations made with the CRyogenic InfraRed Echelle SpectrographCRIRES), attached to ESO’s Very Large Telescope, have now revealed that the atmosphere as a whole, not just the upper atmosphere, has a mean temperature of minus 180 degrees Celsius, and so it is indeed “much hotter” than the surface.

In contrast to the Earth’s atmosphere, most, if not all, of Pluto’s atmosphere is thus undergoing a temperature inversion: the temperature is higher, the higher in the atmosphere you look. (ANI)

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Astronomers devise new technique to measure sizes and shapes of asteroids

February 6, 2009 By admin Leave a Comment

Amsterdam, Feb 5 (ANI): A team of French and Italian astronomers has devised a new method for measuring the size and shape of asteroids, which would increase the number of asteroids that can be measured by a factor of several hundred.

This method takes advantage of the unique capabilities of ESO’s Very Large Telescope Interferometer (VLTI).

“Knowledge of the sizes and shapes of asteroids is crucial to understanding how, in the early days of our Solar System, dust and pebbles collected together to form larger bodies and how collisions and re-accumulation have since modified them,” said Marco Delbo from the Observatoire de la Cote d’Azur, France, who led the study.

Direct imaging with adaptive optics on the largest ground-based telescopes such as the Very Large Telescope (VLT) in Chile, and space telescopes, or radar measurements are the currently favored methods of asteroid measurement.

However, direct imaging, even with adaptive optics, is generally limited to the one hundred largest asteroids of the main belt, while radar measurements are mostly constrained to observations of near-Earth asteroids that experience close encounters with our planet.

Delbo and his colleagues have devised a new method that uses interferometry to resolve asteroids as small as about 15 km in diameter located in the main asteroid belt, 200 million kilometres away.

This is equivalent to being able to measure the size of a tennis ball a distance of a thousand kilometers.

This technique will not only increase the number of objects that can be measured dramatically, but, more importantly, bring small asteroids that are physically very different from the well studied larger ones into reach.

The interferometric technique combines the light from two or more telescopes.

Astronomers proved their method using ESO’s VLTI, combining the light of two of the VLT’s 8.2-metre Unit Telescopes.

“This is equivalent to having vision as sharp as that of a telescope with a diameter equal to the separation between the two VLT Unit Telescopes used, in this case, 47 meters,” said co-author Sebastiano Ligori, from INAF-Torino, Italy.

The researchers applied their technique to the main belt asteroid (234) Barbara. Although it is so far away, the VLTI observations also revealed that this object has a peculiar shape.

“The two parts appear to overlap,” said Delbo. “So, the object could be shaped like a gigantic peanut or, it could be two separate bodies orbiting each other,” he added.

Having proven the validity of their new and powerful technique, the team can now start a large observing campaign to study small asteroids. (ANI)

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Astronomers see stars bursting from ‘dusty cocoons’ in distant galaxy

January 22, 2009 By Rajesh Leave a Comment

Munich, Jan 22 (ANI): Astronomers have uncovered a host of new young, massive and dusty stellar nurseries in nearby galaxy NGC 253, which are, in a way, bursting from their cocoons.

Astronomers from the Instituto de Astrofísica de Canarias (Spain) used NACO, a sharp-eyed adaptive optics instrument on ESO’s Very Large Telescope (VLT), to study the fine detail in NGC 253, one of the brightest and dustiest spiral galaxies in the sky.

Adaptive Optics (AO) corrects for the blurring effect introduced by the Earth’s atmosphere.

This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it smears out the images.

With AO in action, the telescope can produce images that are as sharp as is theoretically possible, as if the telescope were in space.

NACO revealed features in the galaxy that were only 11 light-years across.

“Our observations provide us with so much spatially resolved detail that we can, for the first time, compare them with the finest radio maps for this galaxy – maps that have existed for more than a decade,” said Juan Antonio Fernandez-Ontiveros, the lead author of the paper reporting the results.

Astronomers identified 37 distinct bright regions, a threefold increase on previous results, packed into a tiny region at the core of the galaxy, comprising just one percent of the galaxy’s total size.

The astronomers combined their NACO images with data from another VLT instrument, VISIR, as well as with images from the NASA/ESA Hubble Space Telescope and radio observations made by the Very Large Array and the Very Large Baseline Interferometer.

Combining these observations, taken in different wavelength regimes, provided a clue to the nature of these regions.

“We now think that these are probably very active nurseries that contain many stars bursting from their dusty cocoons,” said Jose Antonio Acosta-Pulido, a member of the team.

NGC 253 is known as a starburst galaxy, after its very intense star formation activity. Each bright region could contain as many as one hundred thousand young, massive stars.

This comprehensive set of data also leads astronomers to conclude that the centre of NGC 253 hosts a scaled-up version of Sagittarius A, the bright radio source that lies at the core of the Milky Way which harbours a massive black hole.

“We have thus discovered what could be a twin of our Galaxy’s Centre,” said co-author Almudena Prieto. (ANI)

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Scientists invent world’s fastest and most sensitive astronomical camera

Use the net to go ‘around the world in 80 telescopes’

Pluto’s lower atmosphere revealed by scientists

Astronomers devise new technique to measure sizes and shapes of asteroids

Astronomers see stars bursting from ‘dusty cocoons’ in distant galaxy

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