Picture of the Week 2012

13 August 2012

Orion Watching Over ALMA

Standing watch over the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA), Orion, the Hunter, shines high in the Chilean night sky. With its distinctive hourglass shape and the three bright stars of Orion’s Belt in the centre, the constellation is easily recognisable. Taken from the southern hemisphere, this image shows Orion’s sword above the Belt. The sword is home to one of the most stunning features of the sky — the Orion Nebula — which appears as the middle “star” in the sword, its fuzzy nebulosity visible to the naked eye under good conditions.

The three ALMA antennas visible in the image represent only a small part of the complete ALMA array, which has a total of 66 antennas. ALMA combines the signals from its antennas, separated over distances of up to 16 kilometres, to form a single giant telescope, using a technique called interferometry. While construction is not due to be completed until 2013, early scientific observations began with a partial set of antennas late in 2011.

At 5000 metres altitude on the Chajnantor Plateau in the foothills of the Chilean Andes, in one of the most arid regions in the world, ALMA is guaranteed outstanding observing conditions. A high, dry site such as Chajnantor is needed because water vapour and oxygen in the Earth’s atmosphere strongly absorb the millimetre and submillimetre wavelengths of light at which ALMA is designed to observe.

In this photograph, the antennas were being tested at ALMA’s Operations Support Facility, located at the slightly lower altitude of 2900 metres. Once tested and fully equipped, they were transported up to the Chajnantor plateau to begin their work.

This image was taken by Adrian Russell, who submitted the photograph to the Your ESO Pictures Flickr group. The Flickr group is regularly reviewed and the best photos are selected to be featured in our popular Picture of the Week series, or in our gallery. In 2012, as part of ESO’s 50th anniversary year, we are also welcoming your historical ESO-related images.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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6 August 2012

From a Dirt Track to the World’s Leading Observatory

ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special Then and Now comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal Observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany.

This pair of pictures shows a view from the entrance of the Paranal Observatory site in northern Chile, looking towards the summit of Cerro Paranal, as seen in 1987 and in the present day.

The Cerro Paranal region was first scouted out as a possible site for the future Very Large Telescope (VLT) in 1983 by a team including ESO’s Director General at that time, Lodewijk Woltjer (see The Messenger, No. 64, pp 5–8 for more information). In 1987 a dirt road to the summit was constructed and a permanent station for monitoring the conditions was established. The historical picture shows the view at that time.

The site testing results were extremely good — the conditions were clearly better than either ESO’s La Silla Observatory or the other sites then under consideration. They led to the decision to site the VLT on Paranal, which was made by the ESO Council in December 1990 (see eso9015).

Much has changed at Paranal in the 25 years since the historical photograph was taken. The summit of the mountain was leveled and a high-quality road put in place, and of course the observatory’s telescopes themselves were constructed. The complete and fully operational observatory can be seen in the present day photograph. On the summit now stand the four 8.2-metre VLT Unit Telescopes, along with the four smaller 1.8-metre Auxiliary Telescopes, used for interferometry, as well as the 2.6-metre VLT Survey Telescope. At the gate many buildings forming the observatory’s basecamp have been erected. For a view from the opposite direction, looking down from the mountaintop over the basecamp, see the earlier Picture of the Week potw1230.

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30 July 2012

Red Cocoon Harbours Young Stars

On Earth, cocoons are associated with new life. There are “cocoons” in space too, but, rather than protecting pupae as they transform into moths, they are the birthplaces of new stars.

The red cloud seen in this image, taken with the EFOSC2 instrument on ESO’s New Technology Telescope, is a perfect example of one of these star-forming regions. This is a view of a cloud called RCW 88, which is located about ten thousand light-years away and is about nine light-years across. It is not made of silk, like a moth’s cocoon, but of glowing hydrogen gas that surrounds the recently formed stars. The new stars form from clouds of this hydrogen gas as they collapse under their own gravity. Some of the more developed stars, already shining brightly, can even be seen peering through the cloud.

These hot young stars are very energetic and emit large amounts of ultraviolet radiation, which strips the electrons from the hydrogen atoms in the cloud, leaving the positively charged nuclei — protons. As the electrons are recaptured by the protons, they can emit H-alpha light, which has a characteristic red glow.

Observing the sky through an H-alpha filter is the easiest way for astronomers to find these star-forming regions. A dedicated H-alpha filter was one of the four filters used to produce this image.


23 July 2012

The Paranal basecamp from above

Looking down from a vantage point at the ESO Very Large Telescope on Cerro Paranal in the Chilean Atacama Desert, the observatory’s basecamp stretches out below. The Paranal Residencia, a haven for those working on the mountain, can be seen near the centre with the dome on its roof. To the left of the Residencia, on the other side of the road, is the basecamp’s gymnasium, and to the left of that is the Mirror Maintenance Building (MMB), where the giant VLT mirrors are periodically cleaned and recoated. Behind the MMB is the site’s power station, and further to the left is the mechanical workshop building. Winding up the mountainside in the foreground is the Star Track, a walking path from the Residencia to the summit.

The Sun had set about a quarter of an hour before this photograph was taken, leaving the basecamp bathed in beautiful orange light. This twilight creates gentle shadows which give the hills great depth. Such a sight at Paranal can only be seen during the so-called "golden hours" before sunrise or after sunset, as direct sunlight during the day results in unforgiving lighting contrasts.

This panoramic photograph was created by ESO Photo Ambassador Gerhard Hüdepohl.

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16 July 2012

An ALMA Antenna on the Move

This photograph shows one of the 12-metre-diameter European antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) being moved at the project’s Operations Support Facility. Since this photograph was taken, this antenna, and others like it, have been put into operation as ALMA has begun scientific observations with a partial array (see eso1137). Most recently, the Call for Proposals for ALMA’s next phase of observations closed on Thursday 12 July. Over 1100 proposals were received from astronomers around the world.

ALMA makes its observations on the Chajnantor plateau at an altitude of 5000 metres. Once construction is completed, ALMA will have an array of 66 high-precision 12-metre- and 7-metre-diameter antennas, spread over distances of up to 16 kilometres, working together as a single telescope at wavelengths of 0.32 to 3.6 millimetres. More than half of the 66 antennas are already on Chajnantor (see ann12035). Twenty-five ALMA antennas are being provided by ESO through a contract with the European AEM Consortium, 25 antennas are being provided by North America, and 16 by East Asia.

The antennas, each weighing about 100 tonnes, are assembled and tested at the Operations Support Facility, high in Chile’s Atacama region, at an altitude of 2900 metres. They are moved from there to the Chajnantor plateau, 5000 metres above sea level, with the help of two specially designed ALMA antenna transporters — huge vehicles that drive on 28 tyres, are 10 metres wide, 20 metres long and 6 metres high, weigh 130 tonnes, and have as much power as two Formula 1 engines. One of the transporters, named Otto, is being used in this photograph, which was taken when the first European antenna was handed over to the observatory in April 2011.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.


9 July 2012

The Cat's Paw Remastered

The Cat’s Paw Nebula is revisited in a combination of exposures from the MPG/ESO 2.2-metre telescope and expert amateur astronomers Robert Gendler and Ryan M. Hannahoe. The distinctive shape of the nebula is revealed in reddish puffy clouds of glowing gas against a dark sky dotted with stars.

The image was made by combining existing observations from the 2.2-metre MPG/ESO telescope of the La Silla Observatory in Chile (see ESO Photo Release eso1003) with 60 hours of exposures on a 0.4-metre telescope taken by Gendler and Hannahoe.

The resolution of the existing 2.2-metre MPG/ESO telescope observations was combined (by using their “luminance” or brightness) with the colour information from Gendler and Hannahoe’s observations to produce a beautiful combination of data from amateur and professional telescopes. For example, the additional colour information brings out the faint blue nebulosity in the central region, which is not seen in the original ESO image, while the ESO data contribute their finer detail. The result is an image that is much more than the sum of its parts.

The well-named Cat’s Paw Nebula (also known as NGC 6334) lies in the constellation of Scorpius (The Scorpion). Although it appears close to the centre of the Milky Way on the sky, it is relatively near to Earth, at a distance of about 5500 light-years. It is about 50 light-years across and is one of the most active star formation regions in our galaxy, containing massive, young brilliant blue stars, which have formed in the last few million years. It is host to possibly tens of thousands of stars in total, some of them visible and others still hidden in the clouds of gas and dust.

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2 July 2012

An Oasis for Astronomers — ESO’s Paranal Residencia Then and Now

ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special Then and Now comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal Observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany.

Since February 2002 (see eso0205), the Paranal Residencia has provided accommodation for people working shifts at ESO’s flagship observatory site. Paranal, in Chile’s Atacama Desert, is the home of ESO’s Very Large Telescope (VLT). This month, our Then and Now photographs — both taken by ESO Photo Ambassador Gerhard Hüdepohl — give us a unique view of how this oasis in the desert was built.

The historical photograph shows the Residencia under construction at the end of 2000. The building was designed by German architecture firm Auer+Weber, and is based around a subterranean L-shape. The building materials have the same colour as the desert, to help it blend into the landscape, and the partially completed central area of the Residencia is reminiscent of an amphitheatre, with stone tiers open to the cloudless sky.

Today, the Residencia looks quite different! Despite the subterranean location, the building’s distinctive design creates an interior with a feeling of open space. The central hall is protected by a 35-metre-wide glazed dome, which allows natural daylight into the building. The sterile amphitheatre of 2000 is reinvented as a lush tropical garden, with a pool at the bottom. Both the garden and the pool are designed to increase the humidity indoors, allowing staff some respite from the extremely arid conditions outside, in one of the driest places on Earth.

Thanks to the Residencia’s unique design, its fame has also spread beyond the astronomy community.  For example, in 2008 the James Bond movie Quantum of Solace filmed key scenes here, with the Residencia playing the role of the “Perla de las Dunas” hotel [1]. In 2009, the Residencia was selected as one of the “top 10 buildings of the decade” by the UK’s Guardian newspaper (see ann0940), and in 2012, the Paranal Observatory, including the Residencia, was featured in Land Rover’s “Perfect Places” ad campaign (see ann12008).

Notes

[1] For more information about James Bond at Cerro Paranal see eso0807, eso0838, and http://www.eso.org/public/outreach/bond/BondatParanal.html

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25 June 2012

Mars, 2099?

On a cold dark night on Mars, in the middle of an arid desert, a narrow road lit by artificial lights winds its way up to a lonely human outpost on the top of an old mountain. Or at least, that’s what a science fiction fan might make of this almost unearthly view.

The photograph actually shows ESO’s Paranal Observatory, home to the Very Large Telescope (VLT), on Earth. Nevertheless, it’s easy to imagine it as a future view of Mars, perhaps at the end of the century. Which is why Julien Girard, who took this photograph, calls it “Mars 2099”.

Located at 2600 metres altitude, ESO’s Paranal Observatory sits in one of the driest and most desolate areas on Earth, in Chile’s Atacama Desert. The landscape is so Martian, in fact, that the European Space Agency (ESA) and NASA test their Mars rovers in this region. For example, an ESA team recently tested the self-steering Seeker rover, as described in ann12048.

This image was taken at twilight, looking southwest towards the VLT, from the VISTA survey telescope on an adjacent peak. To the west lies the Pacific Ocean, only about 12 kilometres from Paranal. Rising up from the Paranal summit, the Milky Way can be seen, bearing the unmistakable mark of the southern sky — the asterism of the Southern Cross.

At Paranal, the skies can be so clear and dark on moonless nights, that the light from the Milky Way alone is enough to cast shadows. This is why ESO chose the site for the VLT, and why the observatory benefits from some of the best observing conditions in the world.

Julien Girard is an ESO astronomer based in Chile, who works at the VLT. He submitted this photograph to the Your ESO Pictures Flickr group. The Flickr group is regularly reviewed and the best photos are selected to be featured in our popular Picture of the Week series, or in our gallery. In 2012, as part of ESO’s 50th anniversary year, we are also welcoming your historical ESO-related images.

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18 June 2012

Yepun’s Laser and the Magellanic Clouds

One of the major enemies of astronomers is the Earth’s atmosphere, which makes celestial objects appear blurry when observed by ground-based telescopes. To counteract this, astronomers use a technique called adaptive optics, in which computer-controlled deformable mirrors are adjusted hundreds of times per second to correct for the distortion of the atmosphere.

This spectacular image shows Yepun [1], the fourth 8.2-metre Unit Telescope of ESO’s Very Large Telescope (VLT) facility, launching a powerful yellow laser beam into the sky. The beam creates a glowing spot — an artificial star — in the Earth’s atmosphere by exciting a layer of sodium atoms at an altitude of 90 km. This Laser Guide Star (LGS) is part of the VLT’s adaptive optics system. The light coming back from the artificial star is used as a reference to control the deformable mirrors and remove the effects of atmospheric distortions, producing astronomical images almost as sharp as if the telescope were in space.

Yepun’s laser is not the only thing glowing brightly in the sky. The Large and Small Magellanic Clouds can be seen, to the left and to the right of the laser beam, respectively. These nearby irregular dwarf galaxies are conspicuous objects in the southern hemisphere, and can be easily observed with the unaided eye. The prominent bright star to the left of the Large Magellanic Cloud is Canopus, the brightest star in the constellation Carina (The Keel), while the one towards the top-right of the image is Achernar, the brightest in the constellation Eridanus (The River).

This image was taken by Babak Tafreshi, an ESO Photo Ambassador.

Notes

[1] The VLT’s four Unit Telescopes are named after celestial objects in the indigenous Mapuche language, Mapudungun. The Unit Telescopes (UTs) are named: Antu (UT1, the Sun); Kueyen (UT2, the Moon); Melipal (UT3, the Southern Cross); and Yepun (UT4, Venus).

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11 June 2012

Cascading Milky Way

Many astronomical photographs capture stunning vistas of the skies, and this is no exception. However, there’s something unusual about this panorama. Behind ESO’s Very Large Telescope (VLT), two streams of stars seem to cascade down like waterfalls, or perhaps rise like smoke columns to the heavens. That’s because this panorama captures the entire dome of the sky, from the zenith down to the horizon, a full 360 degrees around. The two streams are in fact a single band: the plane of our galaxy, the Milky Way, as it arcs across the sky from horizon to horizon. As it passes overhead, it appears to spread out across the whole top edge of the panorama, due to the distortion needed to squeeze the full dome of the sky into a flat, rectangular image.

To understand the picture, imagine that the far left side is attached to the far right, creating a loop around you, and that the top edge is drawn together to a single point overhead. Thus, it encompasses the full dome of the sky above you.

On the left side of the image, the silhouette of the observatory’s windsock on its pole can be seen above the building. To the left of the windsock is the bright smudge of the Small Magellanic Cloud, a neighbouring galaxy of the Milky Way. To the right, in the plane of the Milky Way, is the reddish glow of the Carina Nebula. Above that is the darkness of the Coalsack Nebula, next to the Southern Cross, and slightly higher still are the two bright stars of Alpha and Beta Centauri. The four tall buildings in the image house the 8.2-metre-diameter Unit Telescopes (UTs) of the VLT. Between the two UTs on the right is the smaller building of the VLT Survey Telescope. On the right of the image, the planet Venus glows just above the horizon.

This panorama, which shows not only the VLT on the mountaintop of Cerro Paranal, but also the beautiful sky that the observatory studies, was created by ESO Photo Ambassador Serge Brunier. Just as the VLT’s state-of-the-art technology expands our view of the Universe, Serge has used the most advanced photographic techniques to capture an entire hemisphere of the sky in one image — far more than our eyes could see in a single view.

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4 June 2012

Computing at ESO Through the Ages — The amazing advance of technology

ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special Then and Now comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal Observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany.

Our pair of photographs this month show how the computing power used by ESO has changed dramatically over time. Both photographs show Austrian astronomer Rudi Albrecht in front of ESO’s computer systems, but on dates separated by decades.

In the historical image, taken in 1974 in the ESO offices in Santiago, Chile, we can see Albrecht, pencil in hand, poring over code in front of a teletype. He was working on software for the Spectrum Scanner attached to the ESO 1-metre telescope [1] located at the La Silla Observatory. The data were processed in Santiago using the Hewlett Packard 2116 minicomputer which can be seen behind the printer. This bulky computer, with one processor and a breathtaking 16 kilobytes of magnetic-core memory (!), stored the results on magnetic tape, ready for further processing by visiting astronomers on computers at their home institutes. To handle files on tape that were larger than the available memory, Albrecht developed a virtual memory system, which he contributed to the Hewlett Packard Software Center.

The present-day photograph shows Albrecht in the Data Centre at ESO Headquarters in Garching bei München, Germany, which archives and distributes data from ESO’s telescopes. He is in front of a rack containing a system with 40 processor cores, 138 terabytes of storage capacity and 83 gigabytes of RAM — over 5 million times more than the machine used by him back in 1974! Even the tablet computer he is holding far outperforms the older machine, and provides a modern alternative to pencil and paper.

Over the years, ESO’s computing systems have developed to handle the flood of scientific data from the observatory’s telescopes. Advances in telescope, detector, and computer technology mean that observatories now produce massive quantities of images, spectra, and catalogues. For instance, the two survey telescopes at Paranal, the VST and VISTA, together produce over 100 terabytes of data per year. It’s a far cry from the days of magnetic tape and 16 kilobytes of memory!

Notes

[1] The ESO 1-metre telescope was decommissioned in 1994.


28 May 2012

The Southern Milky Way Above ALMA

ESO Photo Ambassador Babak Tafreshi snapped this remarkable image of the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA), set against the splendour of the Milky Way. The richness of the sky in this picture attests to the unsurpassed conditions for astronomy on the 5000-metre-high Chajnantor plateau in Chile’s Atacama region.

This view shows the constellations of Carina (The Keel) and Vela (The Sails). The dark, wispy dust clouds of the Milky Way streak from middle top left to middle bottom right. The bright orange star in the upper left is Suhail in Vela, while the similarly orange star in the upper middle is Avior, in Carina. Of the three bright blue stars that form an “L” near these stars, the left two belong to Vela, and the right one to Carina. And exactly in the centre of the image below these stars gleams the pink glow of the Carina Nebula (eso1208).

ESO, the European partner in ALMA, is providing 25 of the 66 antennas that will make up the completed telescope. The two antennas closest to the camera, on which the careful viewer can find the markings “DA-43” and “DA-41”, are examples of these European antennas. Construction of the full ALMA array will be completed in 2013, but the telescope is already making scientific observations with a partial array of antennas.

Babak Tafreshi is founder of The World At Night, a programme to create and exhibit a collection of stunning photographs and time-lapse videos of the world’s most beautiful and historic sites against a night-time backdrop of stars, planets and celestial events.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

 

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21 May 2012

Icy Penitents by Moonlight on Chajnantor

Babak Tafreshi, one of the ESO Photo Ambassadors, has captured a curious phenomenon on the Chajnantor plateau, the site of the Atacama Large Millimeter/submillimeter array (ALMA).

These bizarre ice and snow formations are known as penitentes (Spanish for “penitents”). They are illuminated by the light of the Moon, which is visible on the right on the photograph. On the left, higher in the sky, the Large and Small Magellanic Clouds can be faintly seen, while the reddish glow of the Carina Nebula appears close to the horizon on the far left.

The penitentes are natural marvels found in high-altitude regions, such as here in the Chilean Andes, typically more than about 4000 metres above sea level. They are thin spikes and blades of hardened snow or ice, which often form in clusters, with their blades pointing towards the Sun. They attain heights ranging from a few centimetres, resembling low grass, up to five metres, giving an impression of an ice forest in the middle of the desert.

The precise details of the mechanism that forms the penitentes are still not completely understood. For many years, people of the Andes believed the penitentes to be the result of strong winds prevalent in the Andes mountains. However, the strong winds have only a limited role in shaping these icy pinnacles. Nowadays, it is believed that they are the product of a combination of physical phenomena.

The process begins with sunlight shining on the surface of the snow. Due to the very dry conditions in these desert regions, the ice sublimes rather than melts — it goes from solid to gas without melting and passing through a liquid water phase. Surface depressions in the snow trap reflected light, leading to more sublimation and deeper troughs. Within these troughs, increased temperature and humidity means that melting can occur. This positive feedback accelerates the growth of the characteristic structure of the penitentes.

These icy statues are named after the spiked hats of the nazarenos, members of a brotherhood that participates in Easter processions around the world. It is not hard to picture them as an assembly of icy monks, congregating in the moonlight.

The image was taken by the side of the road that leads to ALMA. The observatory, which started Early Science operations on 30 September 2011, will eventually consist of 66 high-precision antennas operating together as a single giant telescope.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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#L


14 May 2012

Getting the VLT Ready for Even Sharper Images

This 360 degree panorama shows one of ESO’s Very Large Telescope (VLT) Unit Telescopes (UT4) whilst it was recently briefly held prisoner by ESO’s engineers. It was surrounded by a temporary cage of scaffolding as part of the preparations for the new Adaptive Optics Facility (AOF). This project will convert UT4 into a fully adaptive telescope. The AOF will correct for the blurring effects of the Earth’s atmosphere and will allow much sharper images to be achieved with the HAWK-I and MUSE instruments.

Many new components are being added to UT4 as part of the AOF. Among these is the deformable secondary mirror (DSM):  a thin-shell mirror, 1.1 metres in diameter, but just 2 millimetres thick. This mirror is thin enough to be easily deformed by more than a thousand actuators, up to a thousand times per second in order to counteract the atmosphere’s distortions. The DSM is the largest adaptive mirror manufactured to date (ann12015). Another vital element is the four Laser Guide Star Facility (4LGSF) — four special telescopes that fire laser beams high into the atmosphere to create artificial stars [1] (ann12012). Finally, the GRAAL and GALACSI adaptive optics modules will be responsible for analysing the light coming back from the laser guide stars.

This picture shows an ESO engineer supervising the work performed on UT4. To allow full access to the telescope, the cell of the primary mirror has been temporarily removed. Cables and pipes have also been removed and new ones have been installed. Mounting brackets have been added in preparation for the installation of the 4LGSF electronic cabinets and launch telescopes.

Notes

[1] The laser beams excite a layer of sodium atoms at an altitude of 90 kilometres in the atmosphere, making them glow as artificial stars.


7 May 2012

Three Very Different Telescopes at La Silla

ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into its history. Once a month during 2012, a special Then and Now Picture of the Week shows how things have changed over the decades at the La Silla and Paranal observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany.

These two photographs were taken on the highest peak of La Silla, a mountain with an altitude of 2400 metres, at the edge of the Chilean Atacama Desert. La Silla was ESO’s first observatory site. The historical photograph, taken in 1975, shows some of the trucks and other equipment used for the construction of the dome of the ESO 3.6-metre telescope, which was underway behind the photographer. On the left are the water tanks for the site.

In the modern-day photograph, three new telescopes have appeared, all looking very different from each other. To the right of the water tanks is the ESO New Technology Telescope (NTT), which had its first light on 23 March 1989. This 3.58-metre telescope was the first ever to have a computer-controlled main mirror, which could adjust its shape during observations to optimise image quality. The octagonal enclosure housing the NTT is another technological breakthrough, ventilated by a system of flaps that makes air flow smoothly across the mirror, reducing turbulence and leading to sharper images.

To the right of the NTT is the Swiss 1.2-metre Leonhard Euler Telescope, which has a more traditional dome-shaped enclosure. It is operated by the Geneva Observatory at the Université de Genève in Switzerland, and had its first light on 12 April 1998. It is used to search for exoplanets in the southern sky; with its first discovery being a planet in orbit around the star Gliese 86 (see eso9855). The telescope also observes variable stars, gamma-ray bursts and active galactic nuclei.

In the foreground on the right is a building nicknamed the sarcofago (sarcophagus). This houses the TAROT (Télescope à Action Rapide pour les Objets Transitoires, or Rapid Action Telescope for Transient Objects), which started work at La Silla on 15 September 2006. This fast moving, relatively tiny 25-centimetre robotic telescope reacts extremely quickly to alerts from satellites about gamma-ray bursts, to pinpoint the positions of these dramatic but fleeting events. Observing these cosmic explosions lets astronomers study the formation of black holes and the evolution of stars in the early Universe. TAROT is operated by a consortium led by Michel Boër from Observatoire de Haute Provence in France.

The NTT is operated by ESO, while the Leonhard Euler Telescope and TAROT are among the national and project telescopes hosted at La Silla. Even today, over 40 years after its inauguration, La Silla remains at the forefront of astronomy.

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30 April 2012

Sun, Moon and Telescopes above the Desert

The otherworldly beauty of Chile’s Atacama Desert, home of ESO’s Very Large Telescope (VLT), stretches to the horizon in this panorama. On Cerro Paranal, the highest peak in the centre of this image, are the four giant Unit Telescopes of the VLT, each of which has a mirror with a diameter of 8.2 metres. On the peak to the left of Cerro Paranal is the VISTA survey telescope. This 4.1-metre telescope surveys broad swathes of the heavens, searching for interesting targets which the VLT, as well as other telescopes on the ground and in space, will study in greater detail.

This region offers some of the best conditions for viewing the night sky found anywhere on our planet. On the right of this 360-degree panorama, the Sun is setting over the Pacific Ocean, throwing long shadows across the mountainscape. On the left, the Moon gleams in the sky. Soon, the night’s observations will begin.

This wonderful panorama was made by Serge Brunier, an ESO Photo Ambassador. It is one of many awe-inspiring images in which he captures ESO’s observatories, their beautiful locations, and the splendour of the skies above them.

Links


23 April 2012

The Moon and the Arc of the Milky Way

ESO Photo Ambassador Stéphane Guisard captured this astounding panorama from the site of ALMA, the Atacama Large Millimeter/submillimeter Array, in the Chilean Andes. The 5000-metre-high and extremely dry Chajnantor plateau offers the perfect place for this state-of-the-art telescope, which studies the Universe in millimetre- and submillimetre-wavelength light.

Numerous giant antennas dominate the centre of the image. When ALMA is complete, it will have a total of 54 of these 12-metre-diameter dishes. Above the array, the arc of the Milky Way serves as a resplendent backdrop. When the panorama was taken, the Moon was lying close to the centre of the Milky Way in the sky, its light bathing the antennas in an eerie night-time glow. The Large and Small Magellanic Clouds, the biggest of the Milky Way's dwarf satellite galaxies, appear as two luminous smudges in the sky on the left. A particularly bright meteor streak gleams near the Small Magellanic Cloud.

On the right, some of ALMA’s smaller 7-metre antennas — twelve of which will be used to form the Atacama Compact Array — can be seen. Still further on the right shine the lights of the Array Operations Site Technical Building. And finally, looming behind this building is the dark, mountainous peak of Cerro Chajnantor.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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16 April 2012

APEX Stands Sentry on Chajnantor

The Atacama Pathfinder Experiment (APEX) telescope looks skyward during a bright, moonlit night on Chajnantor, one of the highest and driest observatory sites in the world. Astronomical treasures fill the sky above the telescope, a testament to the excellent conditions offered by this site in Chile’s Atacama region.

On the left shine the stars that make up the tail of the constellation of Scorpius (The Scorpion). The scorpion’s “stinger” is represented by the two bright stars that are particularly close to each other. Reaching across the sky and looking like a band of faint, glowing clouds is the plane of the Milky Way.

Between Scorpius and the next constellation to the right, Sagittarius (The Archer), which looms over APEX’s dish, a sparkling cluster of stars can be clearly seen. This is the open cluster Messier 7, also known as Ptolemy’s Cluster. Below Messier 7 and slightly to the right is the Butterfly Cluster, Messier 6. Further to the right, just above the edge of APEX’s dish, is a faint cloud which looks like a bright smudge. This is the famous Lagoon Nebula (see eso0936 for a closer view).

With a primary dish diameter of 12 metres, APEX is the largest single-dish submillimetre-wavelength telescope operating in the southern hemisphere. As the telescope’s name suggests, it is blazing a trail for the biggest submillimetre observatory in the world, the Atacama Large Millimeter/submillimeter Array (ALMA), which will be completed in 2013 (eso1137). APEX will share space with the 66 antennas of ALMA on the 5000-metre-high Chajnantor plateau in Chile. The APEX telescope is based on a prototype antenna constructed for the ALMA project, and it will find many targets that ALMA will be able to study in great detail.

ESO Photo Ambassador Babak Tafreshi made this panorama using a telephoto lens. Babak is also the founder of The World At Night, a programme to create and exhibit a collection of stunning photographs and time-lapse videos of the world’s most beautiful and historic sites against a nighttime backdrop of stars, planets and celestial events.

More information

APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (MPIfR), the Onsala Space Observatory (OSO), and ESO, with operations of the telescope entrusted to ESO.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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9 April 2012

All Around Chajnantor — A 360-degree panorama

Although Cerro Chico reaches the remarkable altitude of 5300 metres above sea level, it is only a small mountain in the majestic landscape of the Andean plateaux. Indeed, its own name means simply “small mountain” in Spanish. However, due to its position on the plateau of Chajnantor, the top of Cerro Chico offers an excellent and relatively easy-to-reach vantage point from which to enjoy this stunning view.

This 360 degree panorama picture is centred on the northeast, where the highest volcanoes — most of them above 5500 metres — are seen. In the centre is Cerro Chajnantor itself. To the right, on the plateau, is the Atacama Pathfinder Experiment (APEX) telescope with Cerro Chascon behind it.  Further to the right, to the southeast, the Chajnantor plateau is almost fully visible. In addition to the APEX telescope, three Atacama Large Millimeter/submillimeter Array (ALMA) antennas can be seen, on the right. Many more have been added since this panorama was taken.

On the left of Cerro Chajnantor is Cerro Toco. Further to the left, in the northwest, we can see the distinctive conical shape of Licancabur volcano.

On the Chajnantor plateau, at 5000 metres altitude, the air is so thin and dry that it seems never to fill one’s lungs. Thanks to these extreme conditions, the millimetre and submillimetre radiation coming from the rest of the Universe can pass through what remains of the Earth’s atmosphere above the site, and can be detected from the ground with suitably sensitive telescopes such as ALMA and APEX.

APEX is a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. The telescope is operated by ESO.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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2 April 2012

La Silla, the First Home for ESO’s Telescopes — ESO’s first observatory site Then and Now

ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special Then and Now comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal Observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany.

This historical image was taken around 1970 from the La Silla dormitories, located lower on the mountain than the telescope domes. The photo looks up towards the highest point of the mountain, on the left. The metallic structure visible near the top of this peak is not a telescope, but a water tank for the site. The white dome in the centre of the image is that of the ESO 1-metre Schmidt telescope, which started work in February 1972. On the far right of the image is the ESO 1-metre telescope, just visible over the ridge, and to the left of that one can just see the top of the Grand Prisme Objectif telescope.

In the present-day photograph, the dormitory buildings remain, but more have been built over the decades. The most striking changes, though, are visible around La Silla’s peak on the left. At the highest point is the ESO 3.6-metre telescope, which started operating in November 1976 and is still in use today. The 3.6-metre is home to HARPS, the foremost exoplanet hunter (see eso1134 and eso1214 for some recent results). The 3.6-metre, planned from the inception of ESO, was to crown the La Silla Observatory as its biggest telescope, and was a major engineering feat of its time. The smaller dome visible in front of the 3.6-metre is the 1.4-metre Coudé Auxiliary Telescope, which complemented its bigger neighbour.

To the right of the 3.6-metre is the 3.58-metre New Technology Telescope (NTT), recognisable by the angular, metallic appearance of its enclosure. The NTT, which started operating in March 1989, was the first telescope in the world to use a computer-controlled mirror. It was used as a precursor for the Very Large Telescope, to test many new technologies that were then used in the later telescope.

Other new sights in the modern-day photograph are the workshop building below the water tanks, and the Differential Image Motion Monitor (DIMM), used to measure the atmospheric seeing, located on stilts between the workshop and the ESO 1-metre Schmidt telescope.

Even today, La Silla remains a very active observatory where important discoveries are made. Both the NTT and the 3.6-metre telescope provided vital data which led to the discovery of the accelerating expansion of the Universe — a discovery for which the 2011 Nobel Prize in Physics was awarded.

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