A glowing laser shines forth from the European Southern Observatory’s Very Large Telescope. Piercing the dark Chilean skies, its mission is to help astronomers explore the far reaches of the cosmos. ESO Photo Ambassador Gerhard Hüdepohl was on hand to capture the moment in a stunning portrait of modern science in action. 

We have all gazed up at the night sky and seen the stars gently twinkle as the Earth’s turbulent atmosphere causes their light to shimmer. This is undoubtedly a beautiful sight, but it causes problems for astronomers, who want the crispest possible views. To help them achieve this, professional stargazers use something that sounds as though it has come from science fiction: a laser guide star that creates an artificial star 90 km above the surface of the Earth.

The method by which it achieves this is nothing short of remarkable. The laser energises sodium atoms high in the Earth’s mesosphere, causing them to glow and creating a bright dot that to observers on the ground appears to be a man-made star.

Observations of how this “star” twinkles are fed into the Very Large Telescope’s adaptive optics system, controlling a deformable mirror in the telescope to restore the image of the star to a sharp point. By doing this, the system also compensates for the distorting effect of the atmosphere in the region around the artificial star. The end result is an exceptionally crisp view of the sky, allowing ESO astronomers to make stunning observations of the Universe, almost as though the VLT were above the atmosphere in space.

Links

• Adaptive Optics and the Laser Guide Star: http://www.eso.org/public/teles-instr/technology/adaptive_optics.html
• ESO Photo Ambassadors

Not all spiral galaxies have to be picture-perfect to be striking. Messier 96, also known as NGC 3368, is a case in point: its core is displaced from the centre, its gas and dust are distributed asymmetrically and its spiral arms are ill-defined. But this portrait, taken with the FORS1 instrument on ESO’s Very Large Telescope, shows that imperfection is beauty in Messier 96. The galaxy's core is compact but glowing, and the dark dust lanes around it move in a delicate swirl towards the nucleus. And the spiral arms, patchy rings of young blue stars, are like necklaces of blue pearls.  

Messier 96 lies in the constellation of Leo (The Lion). It is the largest galaxy in the Leo I group of galaxies; including its outermost spiral arms, it spans some 100 000 light-years in diameter — about the size of our Milky Way. Its graceful imperfections likely result from the gravitational pull of other members in the group, or are perhaps due to past galactic encounters. 

A multitude of background galaxies peers through the dusty spiral. Perhaps the most striking of these objects is an edge-on galaxy that — because of a chance alignment — appears to interrupt the outermost spiral arm to the upper left of Messier 96's core.

This image was processed by ESO using the observational data found by Oleg Maliy from Ukraine, who participated in ESO's Hidden Treasures 2010 astrophotography competition [1], organised in October–November 2010, for everyone who enjoys making beautiful images of the night sky using astronomical data obtained with professional telescopes. The image was made with data taken at visible and infrared wavelengths through B, V, and I filters. 

Notes

[1] ESO’s Hidden Treasures 2010 competition gave amateur astronomers the opportunity to search through ESO’s vast archives of astronomical data, hoping to find a well-hidden gem that needed polishing by the entrants. To find out more about Hidden Treasures, visit http://www.eso.org/public/outreach/hiddentreasures/.

The night sky above the 2600-metre-high Cerro Paranal in the Atacama Desert in Chile is dark and clear. So clear, that very long sequences of photos can easily be taken without a single cloud obscuring the stars as they rotate around the southern celestial pole.

The site is home to ESO’s Very Large Telescope (VLT) array. Its four 8.2-metre Unit Telescopes dominate this image made by Farid Char, a student at Chile’s Universidad Católica del Norte. One of the smaller Auxiliary Telescopes is also visible, hiding in the background in the bottom left corner.

But the star of the show is the striking starry sky. Made by combining 450 exposures of 20 seconds each, the image captures the apparent stellar movement during two and a half hours. This movement, signalled by dotted trails, is illusory: the Earth, and not the stars, is rotating as time goes by.

The sequence has also captured the Unit Telescopes as they observe different objects in the night sky over the hours, transforming their precise motions into a seemingly frenetic blur of activity. What’s more, one of the exposures has even caught a shooting star, seen as a small trail above the Auxiliary Telescope in the bottom left of the image.

Links

• Farid Char’s photos

This spectacular aerial view shows the ALMA Operations Support Facility (OSF), located 2900 metres above sea level in the foothills of the Chilean Andes, near San Pedro de Atacama.

ALMA, the Atacama Large Millimeter/submillimeter Array, is currently under construction on the 5000-metre-high Chajnantor plateau. Such a high altitude site is necessary for ALMA’s array of antennas to observe the Universe in millimetre and submillimetre radiation, but the lack of oxygen makes the Array Operations Site (AOS) a very uncomfortable place for people to work. For this reason, as much of the scientific and technical work as possible takes place at the OSF, which is 2100 metres lower in altitude. The antennas are even controlled remotely from the OSF.

In this picture, from the bottom left to the centre right, the North American, the Japanese and the European antenna assembly facilities are clearly distinguishable. In these areas, the antennas are assembled and tested by the partners and their contractors, before being handed over to the Joint ALMA Observatory. At this point, the antennas are moved to the area next to the main OSF building, which is visible in the centre of the picture. Here, they undergo further testing before being transported to the AOS along the 28-kilometre road, which leads off to the right of this image. The camp, which offers accommodation for the personnel working at the site, is seen on the left. In the background, the snow-capped high volcanoes of the Andes are silhouetted against the vivid blue sky. The distinctive conical shape of the volcano Licancabur is clearly recognisable.

The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA.

Links

• About ALMA at ESO
• Joint ALMA Observatory website

A new Very Large Telescope (VLT) image of the Antennae Galaxies gives us what may be the second-best visible-light view yet of this striking pair of colliding galaxies with dramatically distorted shapes. This amazing object takes its name from the long antenna-like "arms" extending far out from the nuclei of the two galaxies, best seen in wider-field images by ground-based telescopes such as the one at this link.

This VLT view focuses instead on the galaxies’ nuclei, where the real action is taking place as the two galaxies merge into a single giant galaxy. Spurred by shock waves created by their gravitational wrestling, the two galaxies have become dotted with brilliant blue hot young stars in star-forming regions, surrounded by glowing hydrogen gas, shown here in pink. The two pale yellow blobs are the cores of the original galaxies, shining with the light of old stars and picked out by delicate lanes of dust. 

The Antennae Galaxies were immortalised in 2006 by one of the NASA/ESA Hubble Space Telescope’s most famous images (composed by ESA’s Hubble group residing at ESO).

If you are hungry for more information about this amazing object, read the just-published ESO press release about the first image from ALMA, the Atacama Large Millimeter/submillimeter Array, which has just started its Early Science observations. ALMA , constructed by ESO and its international partners, observes the Universe in light with millimetre and submillimetre wavelengths — radically different from visible-light and infrared telescopes. ALMA’s view is the best submillimetre-wavelength image ever made of the Antennae Galaxies, despite being just a taster of what ALMA will deliver. The ALMA image was made using test data from only twelve antennas, and as the observatory grows, the sharpness, efficiency, and quality of its observations will increase dramatically.

This image was processed by ESO using the observational data found by Alberto Milani (Italy), who submitted it to ESO’s "Your ESO Pictures" Flickr group.

When light from all four 8.2-metre Unit Telescopes of ESO’s Very Large Telescope (VLT) in Cerro Paranal on 17 March 2011 was successfully combined for the first time (ann11021), ESO Photo Ambassador Gerhard Hüdepohl was there to capture the moment.

Having all four of the Unit Telescopes (UTs) working as one telescope observing the same object was a major step in the development of the VLT. While mostly used for individual observations, the UTs were always designed to be able to operate together as part of the VLT Interferometer (VLTI).

All the UTs are pointed in the same direction, at the same object, although this isn’t obvious because of the wide-angle lens used to take the photo. The light collected by each of the telescopes was then combined using an instrument called PIONIER [1]. When combined, the UTs can potentially provide an image sharpness that equals that of a telescope with a diameter of up to 130 metres.

Two of the four 1.8-metre Auxiliary Telescopes, which are also part of the VLTI, can be seen in the picture together with the UTs. While the larger telescopes are fixed, these smaller instruments, in round enclosures, can be relocated to 30 different stations. With the ATs as part of the VLTI, astronomers can capture details up to 25 times finer than with a single UT.

Gerhard Hüdepohl has lived in Chile since 1997. Aside from taking stunning photos in the Atacama Desert, he works as an electronics engineer at the VLT.

Notes

[1] PIONIER, developed at LAOG/IPAG in Grenoble, France, is a visiting instrument at the Paranal Observatory. PIONIER is funded by Université Joseph Fourier, IPAG, INSU-CNRS (ASHRA-PNPS-PNP) ANR 2G-VLTI ANR Exozodi. IPAG is part of the Grenoble Observatory (OSUG).

Links

• Announcement: Light from all Four VLT Unit Telescopes Combined for the First Time.
• ESO Photo Ambassador website.

This interpretation of a previous Picture of the Week was created by astronomer Alex Parker. It captures some of the essence of Paranal Observatory — a little world where astronomers leave the Earth behind and travel to the stars... metaphorically at least.

The observatory lies deep in the barren Atacama Desert, which can really seem like an alien environment. It is far from civilisation and modern life, a place where visiting astronomers spend their nights gazing out at the wonders of the Universe using ESO’s flagship facility, the Very Large Telescope (VLT). The VLT is the reason why Cerro Paranal was transformed from just another mountain in the Chilean Andes into a base for world-class scientific research.

When night falls over Paranal, and the night sky is aglow with stars, nebulae and nearby galaxies, the unearthly view emphasises our place in the Universe — as Alex Parker so creatively demonstrates — floating through space on a tiny chunk of rock.

Have you made something special using ESO’s images or video? Let us — and other ESO fans — know through our new Flickr group, called Your ESO Pictures.

Links

• Alex Parker is a postdoctoral research fellow at the Harvard-Smithsonian Center for Astrophysics, specialising in planetary science. Visit his website here http://www.astro.uvic.ca/~alexhp/new/home
• The original image of the VLT at Paranal can be viewed here: http://www.eso.org/public/images/potw1119a/
• For more about usage of ESO images and videos, see http://www.eso.org/public/outreach/copyright.html
• For more about the Creative Commons Attribution licence, see http://creativecommons.org/licenses/by/3.0/
• Your ESO Pictures Flickr group: http://www.flickr.com/groups/youresopictures

Deep in the heart of the Atacama Desert, home of the Paranal Observatory, the Sun is setting at the start of another clear night. This charming photograph, taken by ESO Photo Ambassador Gianluca Lombardi shows one of four Auxiliary Telescopes (ATs) that belong to ESO’s Very Large Telescope (VLT) sitting boldly against a vivid sky of pink and blue. The full Moon, seen hovering over the horizon, has a distinctly reddish hue, a phenomenon caused by the scattering of light by Earth’s atmosphere.

When the Moon is close to the horizon, the light we see from it must travel through a greater thickness of the atmosphere, so the effects of scattering are increased. As red light is more resilient to scattering than green or blue, our view of the Moon is reddened. As it happens, the reddening effect is somewhat less pronounced at sites like Paranal, as the clear air contains fewer particles that cause scattering. In addition to this, Paranal’s isolated location, far from civilisation and hence sources of light pollution, makes it a perfect place for ground-based astronomy.

The 1.8-metre Auxiliary Telescopes are integral to the VLT Interferometer (VLTI). Whereas the Unit Telescopes are very often engaged in independent activities, the ATs devote all their time to the interferometer. One advantage of this is that the ATs can be used for regular, long-term monitoring observations, which allow exceptionally precise measurements to be made of object positions; this is known as the Narrow Angle Astrometry mode of the VLTI. The ATs telescopes are mobile and able to relocate between 30 different observing positions. By utilising the entire Paranal platform this way, a separation of 202 metres between ATs is possible — the longest baseline of the VLTI.

Links

• More information: Paranal Telescopes Overview
• ESO Photo Ambassadors
• Take a Virtual Tour of the VLT

As ESO tested the new Wendelstein laser guide star unit by shooting a powerful laser beam into the atmosphere, one of the region’s intense summer thunderstorms was approaching — a very visual demonstration of why ESO’s telescopes are in Chile, and not in Germany. Heavy grey clouds threw down bolts of lightning as Martin Kornmesser, visual artist for the ESO outreach department, took timelapse photographs of the test for ESOcast 34. With purely coincidental timing this photograph was snapped just as lightning flashed, resulting in a breathtaking image that looks like a scene from a science fiction movie. Although the storm was still far from the observatory, the lightning appears to clash with the laser beam in the sky.

Laser guide stars are artificial stars created 90 kilometres up in the Earth’s atmosphere using a laser beam. Measurements of this artificial star can be used to correct for the blurring effect of the atmosphere in astronomical observations — a technique known as adaptive optics. The Wendelstein laser guide star unit is a new design, combining the laser with the small telescope used to launch it in a single modular unit, which can then be placed onto larger telescopes.

The laser in this photograph is a powerful one, with a 20-watt beam, but the power in a bolt of lightning peaks at a trillion (one million million) watts, albeit for just a fraction of a second! Shortly after this picture was taken the storm reached the observatory, forcing operations to close for the night. While we may have the ability to harness advanced technology for devices such as laser guide stars, we are still subject to the forces of nature, not least among them the weather!

Links

• Read more about ESO’s Wendelstein laser guide star unit at: http://www.eso.org/public/announcements/ann11039/

The first of twelve 7-metre diameter ALMA antennas has just been transported on 24 August 2011 to the 5000-metre-high Chajnantor plateau, where the Atacama Large Millimeter/submillimeter Array (ALMA) is under construction. ALMA is a giant radio telescope composed of an array of fifty 12-metre antennas, as well as a smaller array known as the Atacama Compact Array (ACA). This will have a total of four 12-metre antennas and the twelve 7-metre dishes.

The four 12-metre ACA antennas have already been moved up to the high plateau, but this is the first of the smaller 7-metre dishes — which put the “compact” into Atacama Compact Array — to reach Chajnantor. It is seen in the centre of this photograph, surrounded by some of the other ALMA antennas. Penitentes ice formations are seen in the foreground.

The larger 12-metre antennas of the main array cannot be placed closer than 15 metres apart as they would otherwise bump into each other. This minimum separation between antennas governs the maximum scale of the features that they can detect in the sky. This means that the main array cannot observe the broadest features of extended objects such as giant clouds of molecular gas in the Milky Way, or nearby galaxies. The ACA is specifically designed to help ALMA make better observations of these extended objects. Its smaller 7-metre antennas can be placed closer together, making them better able to measure the broader structures that the main array misses.

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.

All of the ACA antennas are being provided by Japan through a contract with MELCO (Mitsubishi Electric Corporation). ALMA will also have 25 12-metre antennas provided by ESO, and 25 by NRAO.

Links

• For more information about ALMA at ESO
• The Joint ALMA Observatory website

ALMA, the Atacama Large Millimeter/submillimeter Array, will be initially composed of 66 antennas, designed to observe the Universe in millimetre and submillimetre radiation. The main array will consist of fifty 12-metre antennas that can be spread over distances from 150 metres to 16 kilometres. In addition to the main array, ALMA will also have a compact array, composed of four 12-metre antennas plus twelve 7-metre antennas. By using the technique of interferometry, ALMA will work as a single giant telescope, enabling astronomers to observe the cold universe with unprecedented sensitivity and resolution. From the high altitudes of the Andes, ALMA will provide a revolutionary contribution to the search for our cosmic origins.

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.

Just as the Sun rises in the east and sets in the west, so do the stars appear to slowly march across the sky. Their leisurely pace is imperceptible to a casual observer, but you can test the effect for yourself: on the next clear night note the position of a bright star, and then check again a few hours later. The change is not caused by the motion of the stars themselves, but rather the rotation of the Earth.

Long-exposure photography is the ideal way to capture this motion. A camera is set up on a tripod, and the shutter opened to the sky. Normal snapshots gather light for a fraction of a second, but these special images need starlight to pour onto them for much longer, like a bucket collecting rainwater.

To obtain this image, ESO Photo Ambassador Gianluca Lombardi collected light for a total of 25 minutes. This may not seem like a long time, but the streaks of light in the night sky tell a different story.  The Earth has rotated so that the pin-pricks of starlight have become star trails. In the top left, the trails form arcs around the southern celestial pole, which is outside the photograph. The ghostly traces of someone walking across the Paranal observing platform can also be seen.

Many familiar and outstanding pictures of astronomical objects are obtained using the same principle of accumulating light over a long period of time to build up an image. It is common for telescopes to gather light for several hours to make a single picture. This brings with it an additional challenge: the Earth rotating means that the telescope must also move to keep track of its target.

Links

• ESO Photo Ambassadors

The night sky above Cerro Paranal, the home of ESO’s Very Large Telescope (VLT), is dark and dotted with the bright stars of the Milky Way, and more distant galaxies. But it is very rare to see the ground contrasting with the sky as markedly as in this photograph, which shows a gentle layer of white snow dotted with darker spots of the desert terrain beneath.

The picture was taken last week, shortly before sunrise, by ESO Photo Ambassador Yuri Beletsky, who works as an astronomer at the La Silla Paranal Observatory. He captured not only the beautiful snowy landscape of the Atacama and the mountaintop domes of the VLT, but also an incredible night sky. To the left of the VLT is a satellite trail, and to the right is the trail of a meteor.

Cerro Paranal is a 2600-metre-high mountain located in the Chilean Atacama Desert. It is a very dry place with humidity often dropping below 10 percent and rainfall of less than 10 millimetres per year. Snow, however, does occasionally fall in the desert, providing fleeting but magnificent views such as this one.

Links

• ESO Photo Ambassadors webpage
  

#L

The hazy and aptly named Fine Ring Nebula, shown here, is an unusual planetary nebula. Planetary nebulae form when some dying stars, having expanded into a red giant phase, expel a shell of gas as they evolve into white dwarfs. Most planetary nebulae are either spherical or elliptical in shape, or bipolar (featuring two symmetric lobes of material).

But the Fine Ring Nebula — captured here by the ESO Faint Object Spectrograph and Camera mounted on the New Technology Telescope at the La Silla Observatory in Chile — looks like an almost perfect circular ring. Astronomers believe that some of these more unusually shaped planetary nebulae are formed when the progenitor star is actually a binary system. The interaction between the primary star and its orbiting companion shapes the ejected material.

The stellar object at the centre of the Fine Ring Nebula is indeed thought to be a binary system, orbiting with a period of 2.9 days. Observations suggest that the binary pair is almost perfectly face-on from our vantage point, implying that the planetary nebula’s structure is aligned in the same way. We are looking down on a torus (doughnut shape) of ejected material, leading to the strikingly circular ring shape in the image.

Planetary nebulae are shaped by the complex interplay of many physical processes. Not only can these celestial objects be admired for their beauty, but the study of precisely how they form their striking shapes is a fascinating topic in astronomical research.

This image was made using multiple filters: light observed through B and O-III filters is shown in blue, V is shown in green, R is shown in orange, and H-alpha in red. The image is approximately 200 arcseconds across.

This unusual 360-degree panoramic projection reveals the observing site from a fresh perspective. In the centre of the image, staff at Paranal have gathered to watch the sunset. On the right, the enclosures of the VLT’s Unit Telescopes can be seen: vast machines, each with a primary mirror 8.2 metres across and weighing 23 tonnes. Also visible are several of the smaller 1.8-metre Auxiliary Telescopes, which complement the Unit Telescopes. On the left of the picture is the control building, from where the telescopes are operated remotely during observations. No one remains inside the telescope domes after they are opened.

Since first light in 1998 the Very Large Telescope has been used by ESO astronomers to study the Universe, including some of the most exotic phenomena known, such as exoplanets, supermassive black holes, and gamma-ray bursts.

An amazing interactive virtual tour of Paranal is available here.

The MPG/ESO 2.2-metre telescope at La Silla in Chile is a powerful instrument that can capture distant celestial objects, but it has been used here to image a heavenly body that is much closer to home: the Moon. The data used for this image were selected by Andy Strappazzon from Belgium, who participated in ESO’s Hidden Treasures 2010 astrophotography competition. Andy’s composition of the Moon was the fourth highest ranked entry in the competition.

This image of the crescent Moon shows sunlight skimming across the heavily pocked surface, filling its craters with shadows. This is a fairly flat region of the Moon, but elsewhere, high mountains can be found, with some peaks reaching about 5000 metres. When backlit by the Sun, these mountains cast long shadows on the lunar surface. In the 1600s, Galileo Galilei used these long shadows to determine the height of the peaks.

At the Moon’s poles (not seen in this picture), some craters are permanently shadowed and the floors of some may have not seen sunlight for billions of years. Scientists had long suspected that these dark and constantly cold regions of the Moon could harbour water ice, but it wasn’t until late 2009 that evidence for this was found.

In a NASA mission called LCROSS (Lunar Crater Observation and Sensing Satellite), a spent rocket booster was sent on a one-way collision course to the Moon’s south pole, while the remaining part of the spacecraft hunted for evidence of water in the ejected debris. The mission was a success and its findings confirmed the presence of water ice within these dark craters. The finding has important implications for the future of human exploration of the Moon and elsewhere in the Solar System.

This view of the Moon was taken through a narrowband red filter (H-alpha). The height of the image is about 30 arcminutes.

This image was processed by ESO using the observational data found by Andy Strappazzon (Belgium) [1], who participated in ESO’s Hidden Treasures 2010 astrophotography competition [2], organised by ESO in October–November 2010, for everyone who enjoys making beautiful images of the night sky using astronomical data obtained with professional telescopes.

Notes

[1] Andy searched through ESO’s archive and identified datasets that he used to compose his image of the Moon, which was the fourth highest ranked entry in the competition, out of almost 100 entries. His original work can be seen here.

[2] ESO’s Hidden Treasures 2010 competition gave amateur astronomers the opportunity to search through ESO’s vast archives of astronomical data, hoping to find a well-hidden gem that needed polishing by the entrants. To find out more about Hidden Treasures, visit http://www.eso.org/public/outreach/hiddentreasures/.

Two galaxies, about 50 million light-years away, are locked in a galactic embrace — literally. The Seyfert galaxy NGC 1097, in the constellation of Fornax (The Furnace), is seen in this image taken with the VIMOS instrument on ESO’s Very Large Telescope (VLT). A comparatively tiny elliptical companion galaxy, NGC 1097A, is also visible in the top left. There is evidence that NGC 1097 and NGC 1097A have been interacting in the recent past.

Although NGC 1097 seems to be wrapping its companion in its spiral arms, this is no gentle motherly giant. The larger galaxy also has four faint jets — too extended and faint to be seen in this image — that emerge from its centre, forming an X-shaped pattern, and which are the longest visible-wavelength jets of any known galaxy. The jets are thought to be the remnants of a dwarf galaxy that was disrupted and cannibalised by the much larger NGC 1097 up to a few billion years ago.

These unusual jets are not the galaxy’s only intriguing feature. As previously mentioned, NGC 1097 is a Seyfert galaxy, meaning that it contains a supermassive black hole in its centre. However, the core of NGC 1097 is relatively faint, suggesting that the central black hole is not currently swallowing large quantities of gas and stars. Instead, the most striking feature of the galaxy’s centre is the ring of bright knots surrounding the nucleus. These knots are thought to be large bubbles of glowing hydrogen gas about 750–2500 light-years across, ionised by the intense ultraviolet light of young stars, and they indicate that the ring is a site of vigorous star formation

With this distinctive central star-forming ring, and the addition of numerous bluish clusters of hot, young stars dotted through its spiral arms, NGC 1097 makes a stunning visual object.

The data were originally taken in 2004 (see eso0438) with the VIMOS instrument on the VLT, and additional colour information from an image taken by amateur astronomer Robert Gendler has been superimposed. The VLT data were taken through three visible-light filters: R (at a wavelength of 652 nanometres, and shown here in red), V (a wavelength of 540 nanometres, shown in green), and B (456 nanometres, shown in blue). The image covers a region of approximately 7.7 x 6.6 arcminutes on the sky.

ESO Photo Ambassador Gianluca Lombardi was in the perfect position to capture a crisp dusk view of Auxiliary Telescope (AT) 2, on Cerro Paranal. Once the Sun sets, the cloudless skies above the Chilean desert will be filled with stars, and AT2 will begin its work. In the background on the left is Cerro Armazones, with a road zigzagging to its peak, home of the future European Extremely Large Telescope. Site-testing equipment can be seen on the peak. The lower peak to the right of Cerro Armazones is the site of smaller telescopes operated by the Instituto de Astronomía of the Universidad Católica del Norte.

There are four ATs on Cerro Paranal, which form part of the Very Large Telescope (VLT). They are used for a special technique called interferometry, which allows multiple ATs, or the even larger Unit Telescopes, to combine their power and see details up to 25 times finer possible than with the individual telescopes.

The round AT enclosure shown in the photo is made from two sets of three segments, which were closed at the time the picture was taken. Its job is to protect the delicate 1.8-metre telescope from the desert conditions. The enclosure is supported by the boxy transporter section, which also contains electronics cabinets, liquid cooling systems, air-conditioning units, power supplies, and more. During astronomical observations the enclosure and transporter are mechanically isolated from the telescope, to ensure that no vibrations compromise the data collected.

The transporter section runs on tracks, so the ATs can be moved to 30 different observing locations. As the VLT Interferometer (VLTI) acts rather like a single telescope as large as the group of telescopes combined, changing the positions of the ATs means that the VLTI can be adjusted according to the needs of the observing project.

Links

• More info
• ESO Photo Ambassadors

It’s one of the closest galaxies to Earth, but the Carina Dwarf Galaxy is so dim and diffuse that astronomers only discovered it in the 1970s. A companion galaxy of the Milky Way, this ball of stars shares features with both globular star clusters and much larger galaxies.

Astronomers believe that dwarf spheroidal galaxies like the Carina Dwarf are very common in the Universe, but they are extremely difficult to observe. Their faintness and low star density mean that it is easy to simply see right through them. In this image, the Carina Dwarf appears as many faint stars scattered across most of the central part of the picture. It is hard to tell apart stars from the dwarf galaxy, foreground stars within the Milky Way and even faraway galaxies that poke through the gaps: the Carina Dwarf is a master of cosmic camouflage.

The Carina Dwarf’s stars show an unusual spread of ages. They appear to have formed in a series of bursts, with quiet periods lasting several billion years in between them. It lies around 300 000 light-years from Earth, which places it further away than the Magellanic Clouds (the nearest galaxies to the Milky Way), but significantly closer to us than the Andromeda Galaxy, the closest spiral galaxy.

So, despite being small for a galaxy, its proximity to Earth means that the Carina Dwarf appears quite large in the sky, just under half the size of the full Moon — albeit very much fainter. This makes it fit comfortably within the field of view of ESO’s Wide Field Imager, an instrument designed for making observations of large parts of the sky. Although this image in itself is not so striking, it is likely the best image of the Carina Dwarf Galaxy to date.

The image was made using observations from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at La Silla, and from the Victor M. Blanco 4-metre telescope at the Cerro Tololo Inter-American Observatory.

After nightfall on 15 June 2011 in Garching, near Munich, Germany, a blood-red Moon rose above the horizon. This striking phenomenon was caused by a total lunar eclipse in progress at moonrise, and it was captured in the skies over the European Southern Observatory’s Headquarters.

A lunar eclipse takes place only when the Moon, Earth and Sun are exactly aligned. When the Moon passes through the shadow cast by the Earth, our planet blocks the path of direct sunlight to the lunar surface and a total eclipse occurs. This event can only happen on the night of a full Moon.

Unlike the better known solar eclipses, the Moon doesn’t completely disappear from sight during a total lunar eclipse. Instead it appears painted blood red, giving it the ominous nickname of “blood Moon”. The reddish colour is caused by scattered sunlight that has passed through the Earth’s atmosphere — the same effect that causes sunsets and sunrises to turn the sky a reddish colour.

Last week’s eclipse was rare in that it was the longest total lunar eclipse in more than a decade, lasting almost two hours. The year 2000 saw the last lunar eclipse lasting as long as this one, while the next won’t occur until 2018.

ESO’s Headquarters in Garching function as an administrative and technical centre for ESO’s operations, with astronomers from all over the world gathering here to carry out cutting-edge scientific research.

ESO Photo Ambassador Gianluca Lombardi used a remote shutter release and a 30-second exposure to take this night-time shot of himself sitting on a railing on the observing platform of the ESO Very Large Telescope (VLT). The VLT is on Cerro Paranal, at an altitude of 2600 metres in Chile’s Atacama Desert, one of the driest regions on Earth. The viewing conditions at Paranal are so superb that on a clear moonless night it is possible to see shadows cast by the light of the Milky Way alone.  

In this photograph, however, the Moon is up, appearing as a bright light due to the long exposure. It is about to dip behind the VLT’s Unit Telescope 4 (UT4), named Yepun, and the shadows thrown by the moonlight are lengthening across the 200-metre width of the observing platform. The other three UTs stand in the background. From left to right they are known as Antu (UT1), Kueyen (UT2), and Melipal (UT3) in the indigenous Mapuche language. One of the four 1.8-metre Auxiliary Telescopes, distinguishable by its round enclosure, is visible in front of Antu, on the left.

Links

• ESO Photo Ambassadors

This spectacular approximately 230-degree panoramic photograph of ESO’s Very Large Telescope (VLT), taken by ESO Photo Ambassador Gerhard Hüdepohl, gives us an inspiring view of a slice of the sky, encompassing both our nearest celestial neighbour and star clusters hundreds of light-years away.

The VLT’s four large Unit Telescopes dominate the foreground. With gigantic mirrors 8.2 metres across, they allow us to peer into space and see things four billion times fainter than we can see with our eyes alone. Also visible are the round enclosures of the four 1.8-metre Auxiliary Telescopes, one to the left of the Unit Telescopes and three to the right. This observatory has an excellent location, on Cerro Paranal in the Chilean Atacama Desert. It is so high, at 2600 metres altitude, that what looks like the rippling ocean to the west, on the left of the image, is in fact the cloud layer below the mountaintop. The Pacific Ocean is indeed in this direction, but lies below the clouds. 

The slice of sky visible in the photograph contains a wealth of astronomical objects, including several that are well known. The bright orb above the blanket of cloud is actually the Moon, which is illuminating the telescopes, and also the sky. Soon it will dip below the horizon and a deeper darkness will cover the mountain.

Just above the Moon is what appears to be a bright star, but is in fact the planet Jupiter. A large gas giant, it is one of the brightest celestial objects in the night sky. The tightly grouped collection of stars near the top middle of the photograph is a cluster called the Pleiades, often known as the Seven Sisters. Above the Unit Telescope second from the left is the bright star Capella, while the stars Pollux and Castor, which represent the heads of Gemini (The Twins), can be seen above and slightly to the right of the right-most Unit Telescope. Above the shadowed Auxiliary Telescope to the right is the open cluster Praesepe, also known as the Beehive Cluster, or Messier 44. Above it, near the top of the image, is the bright star Procyon.

Links

• More information about the VLT
• ESO Photo Ambassadors webpage

This is a helicopter view of the Atacama Large Millimeter/submillimeter Array (ALMA) Operations Support Facility (OSF) site. In the foreground is the AEM Consortium’s [1] facility where the European antennas are assembled and tested. Seven of the 25 European antennas can be seen, pointing towards the sky. More parts, including a receiver cabin and antenna base, await the next assembly. Each antenna has a dish 12 metres in diameter, and weighs about 95 tonnes.

Once an antenna is assembled and ready, it is handed over to the ALMA project and moved to the nearby OSF technical area, which is the area in the background, where more antennas can be seen. Here, it is integrated into the rest of the observatory’s systems. Finally, after further tests by the ALMA team, it is moved from the 2900 metres high OSF to its workplace, the Array Operation Site (AOS), located at an altitude of 5000 metres on the Chajnantor Plateau.

Also in the background, the two bright yellow ALMA antenna transporter vehicles, which are responsible for moving the antennas around and between the OSF and AOS sites, can be seen in their parking area. Further in the distance are the majestic snow-covered peaks of the high Andes, with the distinctive conical shape of the 5920-metre Licancabur volcano on the right.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO, the European partner in ALMA, is providing 25 12-metre antennas through a contract with the European AEM Consortium. ALMA will also have 25 North American antennas, and 16 East Asian antennas.

Notes

[1] The AEM Consortium is composed of Thales Alenia Space, European Industrial Engineering, and MT-Mechatronics.

The first of twelve 7-metre antennas has been handed over to the Atacama Large Millimeter/submillimeter Array (ALMA) observatory in Chile. ALMA will have an array of fifty antennas with 12-metre diameter dishes, as well as a system known as the Atacama Compact Array (ACA), provided by Japan, of which this new 7-metre antenna is part. The ACA will have a total of twelve 7-metre dishes and four 12-metre dishes, and will be particularly important for ALMA’s observations of the broader structure in extended astronomical objects such as giant clouds of molecular gas.

The 7-metre antenna is seen here at the ALMA Operations Support Facility (OSF), at an altitude of 2900 metres in the foothills of the Chilean Andes. These antennas are being provided by Japan through a contract with MELCO (Mitsubishi Electric Corporation).

The antennas are manufactured in Japan, then disassembled and shipped to Chile. They are reassembled and tested at the OSF, before being handed over to the observatory. After further testing, and the installation of sensitive receivers, each of the antennas will take its place — together with antennas from the other ALMA partners — on the plateau of Chajnantor at 5000 metres altitude, where the ALMA telescope will operate.

ALMA is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA.

Links

• Announcement of the handover of the 7-metre antenna
• For more information about ALMA at ESO
• The Joint ALMA Observatory website

This new image of the spiral galaxy NGC 3244 was taken with the help of the President of the Czech Republic, Václav Klaus, during his visit to ESO’s Paranal Observatory [1], on the night of 6 April 2011. The Czech Republic joined ESO in 2007, and this was the first visit of the country’s President to an ESO site.

This galaxy has attracted considerable interest from astronomers over the past nine months, thanks to the violent death of one of its stars, which was discovered on 27 June 2010. This supernova explosion, now known as Supernova 2010ev (SN 2010ev), is still visible as the — now faint — blue dot nestled within one of the thick spiral arms just to the left of the galaxy’s nucleus.

To the right of  the galaxy, an unremarkable foreground star in our own Milky Way, TYC 7713-527-1, shines brightly enough to catch our attention. Although the star seems a great deal brighter than SN 2010ev, this is actually an illusion created by the large difference in the distances of the two objects. The galaxy is much further away, at a distance of about 90 million light years, while the star lies thousands of times closer, within our own galaxy.

At its brightest, SN 2010ev reached an apparent magnitude of about 14, making it about 1000 times dimmer than the naked eye can see, but it was still the third brightest supernova observed in 2010. In fact, if the supernova had been as close to Earth as TYC 7713-527-1, it would have been easily visible to the naked eye, unlike the aforementioned star.

The image was taken using the FORS2 instrument on the ESO Very Large Telescope (VLT). The filters used for the image were B, V and R, which were coloured blue, green and red respectively. A framed print of the President’s Galaxy has been presented to Václav Klaus, as a memento of his visit to Paranal.

Notes

[1] For more information about the visit of the President of the Czech Republic, Václav Klaus, see the organisation release

Links

• Read more about SN 2010ev

A total eclipse of the Moon is an impressive spectacle. But it also provides another viewing opportunity: a dark, moonlight-free starry sky. At Cerro Paranal in the Chilean Atacama Desert, one of the most remote places in the world, the distance from sources of light pollution makes the night sky all the more remarkable during a total lunar eclipse.  

This panorama photo, taken by ESO Photo Ambassador Yuri Beletsky, shows the view of the starry sky from the site of ESO’s Very Large Telescope (VLT) at Cerro Paranal during the total lunar eclipse of 21 December 2010. The reddish disc of the Moon is seen on the right of the image, while the Milky Way arches across the heavens in all its beauty. Another faint glow of light is also visible, surrounding the brilliant planet Venus in the bottom left corner of the picture. This phenomenon, known as zodiacal light, is produced by sunlight reflecting off dust in the plane of the planets. It is so faint that it’s normally obscured by moonlight or light pollution.    

During a total lunar eclipse, the Earth’s shadow blocks direct sunlight from the Moon. The Moon is still visible, red in colour because only light rays at the red end of the spectrum are able to reach the Moon after being redirected through the Earth’s atmosphere (the blue and green light rays are scattered much more strongly).

Interestingly the Moon, which appears above one of VLT’s Unit Telescopes (UT2), was being observed by UT1 that night. UT1 and UT2 are also known as Antu (meaning The Sun in Mapudungun, one of Chile’s native languages) and Kueyen (The Moon), respectively.

Links

• ESO Photo Ambassadors webpage

#L

ESO Photo Ambassador Gerhard Hüdepohl has captured yet another rare sight.

Yesterday, in the morning of 1 May 2011, about an hour before sunrise, five of our Solar System’s eight planets and the Moon could be seen from Paranal. The four planets in the sky were Mercury, Venus, Mars and Jupiter, and they were joined by the crescent Moon to create this wonderful photo opportunity of a planetary conjunction — two or more celestial bodies seen near each other in the sky, usually from the Earth.

In this photo, the bright crescent of the Moon is illuminated by the Sun (which is just below the horizon), while the darker part receives only light reflected from the surface of the Earth. Venus is the highest and brightest planet, with Mercury below and to the right. Jupiter is directly below Venus, but much closer to the horizon. Mars can be seen just below and to the left of Jupiter; the separation in the sky was less than half a degree. The fifth planet in the photograph is of course the Earth, providing our vantage point for this spectacular conjunction.

This view from Cerro Paranal shows some nearby, and more distant, mountain peaks in the Atacama Desert, one of the driest places on this planet. Three of the ESO Very Large Telescope’s 1.8-metre Auxiliary Telescopes (ATs) are silhouetted in the foreground. Just to the right of the leftmost AT is Cerro Armazones, site of the future European Extremely Large Telescope (E-ELT). Armazones is about 20km from Paranal. Between the ATs on the right is the distant volcano Llullaillaco, on the border of Chile and Argentina. It is much further away than Armazones, at a distance of 190km, but the exceptionally clear atmospheric conditions in the Atacama Desert provide a razor-sharp view, despite the distance. These conditions also help to make the region one of the best in the world for astronomical observations.

The image without annotations can be downloaded from: http://www.eso.org/public/images/potw1118a_clean/


Links

• Unannotated image
• Article about the May conjunction in Sky & Telescope
• An animation made by Sky & Telescope, showing the progression of the conjunction throughout late April and May (note that the positions of the planets relative to the horizon are tilted, when compared to Gerhard Hüdepohl’s photograph, as this animation was made for observers in North America) : http://media.skyandtelescope.com/video/planet-animation-may2011.mov

On Cerro Paranal, the 2600-metre-high mountain in Chile’s Atacama Desert that is home to ESO’s Very Large Telescope, the atmospheric conditions are so exceptional that fleeting events such as the green flash of the setting Sun are seen relatively frequently. Now, however, ESO Photo Ambassador Gerhard Hüdepohl has captured an even rarer sight: a green flash from the Moon, instead of the Sun. The photographs are very probably the best ever taken of the Moon’s green flash.

Gerhard was surprised and delighted to catch the stunning green flash in this series of photographs of the setting full Moon crossing the horizon, taken on a clear early morning from the Paranal Residencia.

The Earth’s atmosphere bends, or refracts, light — rather like a giant prism. The effect is greater in the lower denser layers of the atmosphere, so rays of light from the Sun or Moon are curved slightly downwards. Shorter wavelengths of light are bent more than longer wavelengths, so that the green light from the Sun or Moon appears to be coming from a slightly higher position than the orange and red light, from the point of view of an observer. When the conditions are just right, with an additional mirage effect due to the temperature gradient in the atmosphere, the elusive green flash is briefly visible at the upper edge of the solar or lunar disc when it is close to the horizon.

Gerhard Hüdepohl was born in Germany, and has lived in Chile since 1997, where he works as an Electronics Engineer at ESO’s Very Large Telescope.

Some places on Earth can seem like alien environments, as this stunning panorama shows. It is not the strange surface of an exoplanet, but rather the Chajnantor Plateau in the Chilean Andes. This unearthly location is home to ALMA, the Atacama Large Millimeter/submillimeter Array. Chajnantor was chosen because the rarefied atmosphere above this very high site is so dry that, unlike at most other places on Earth, it is largely transparent to the wavelengths of light that ALMA is designed to detect.

At the centre of the image, the darker, rounded shape of the peak of Cerro Chajnantor, 5600 metres high, can be spotted, followed slightly to the left in the far distance by the conical shape of the 5930-metre Licancabur volcano. The flat area in front, at an altitude of 5000 metres, is the Chajnantor Plateau, the ALMA Array Operations Site. Here the 66 ALMA antennas can be arranged in different configurations, where the maximum distance between antennas can vary from 150 metres to 16 kilometres. The clustered white peaks on the right in the foreground are penitentes, formed by the sublimation of snow in an extremely high altitude and very dry environment. This area of the Chilean Andes borders Bolivia and Argentina.

ALMA will give astronomers an unprecedented window on the cosmos, enabling groundbreaking studies into areas such as the physics of the cold Universe, the first stars and galaxies, and even directly imaging the formation of planets. ALMA, which will begin scientific observations in 2011, is the largest astronomical project in existence and is a truly global partnership between the scientific communities of East Asia, Europe and North America with Chile. ESO is the European partner in ALMA.

An amazing interactive virtual tour of Chajnantor is available here.

This panorama photograph shows the European Southern Observatory’s Headquarters in Garching, near Munich, Germany. The image shows the view from the roof of the main building just after sunset. This is the scientific, technical and administrative centre for ESO’s operations, and the base from which many astronomers conduct their research. The scientists, technicians and administrators who work here come from many different backgrounds, but all have one thing in common: a passion for astronomy.

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. ESO operates telescopes at three observing sites in Chile: La Silla, Paranal and Chajnantor. In addition, Cerro Armazones, near Paranal has been selected as the site for the European Extremely Large Telescope (E-ELT).

ESO provides state-of-the-art research facilities to astronomers and is supported by Austria, Belgium, Brazil, the Czech Republic, Denmark, Finland, France, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. The ESO Headquarters reflects this multicultural spirit of cooperation and is the workplace for astronomers from around the globe.

This image is available as a mounted image in the ESOshop.

#L

Deep in the Chilean Atacama Desert, far from sources of light pollution and other people-related disturbances, there is a tranquil sky like few others on Earth. This is the site for the European Southern Observatory's Very Large Telescope, a scientific machine at the cutting-edge of technology.

In this panoramic photograph, the Large and Small Magellanic Clouds — satellite galaxies of our own — glow brightly on the left, while the VLT’s Unit Telescope 1 stands vigil on the right. Appearing to bridge the gap between them is the Milky Way, the plane of our own galaxy. The seemingly countless stars give a sense of the true scale of the cosmos. Every night ESO astronomers rise to the challenge of studying this vista to make sense of the Universe.

This awe-inspiring image was taken by ESO Photo Ambassador Yuri Beletsky. Born in Belarus, Yuri now lives in Chile where he works as an astronomer. The dark skies above the Atacama Desert provide him with splendid opportunities to reveal the majesty of our cosmos, which he is keen to share.

Links

• ESO Photo Ambassadors page

When completed, the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) will be spread across the Chajnantor plateau in the Chilean Andes over distances of up to 16 kilometres, but they will work in unison, to form what is known as an interferometer. In doing so, ALMA will be more powerful than the sum of its parts, acting like a single giant telescope as large as the whole collection of antennas.

The 66 ALMA antennas are not all the same. A main array of fifty antennas with 12-metre dishes will be complemented by the Atacama Compact Array (ACA) of twelve smaller 7-metre dishes and four additional 12-metre dishes. The ACA dishes are being constructed by Mitsubishi Electric Corporation (MELCO). Three of them are shown in this photograph of the MELCO Site Erection Facility at the ALMA Operations Support Facility (OSF) site. The OSF is at an altitude of 2900 metres, from which the completed dishes are transported along a 28 km road to the 5000-metre altitude of the Chajnantor plateau.

On the left is one of the 7-metre dishes, clearly smaller than its neighbours. The other two dishes both have a diameter of 12 metres, but subtle differences in their design can be seen. This is because the dish on the right was originally a prototype, used for testing during the early stages of the project, which has since been retrofitted with elements from the final design of the dish in the centre. Once ready, all these dishes will take their places on the high Chajnantor plateau.

The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA.

This photograph was taken by ESO Photo Ambassador José Francisco Salgado.

Links

• ESO Photo Ambassadors webpage.

The night of 19 March saw an unusual coincidence of astronomical events: the full Moon occurred at almost exactly the same time as the Moon was closest to Earth in its elliptical orbit (the point called perigee). The combination of the Moon being both full and relatively close to the Earth made it look significantly bigger and brighter than usual. This panoramic photograph, taken by ESO Photo Ambassador Gerd Hüdepohl, captures this so-called "supermoon" as seen from Cerro Paranal, home of ESO's Very Large Telescope (VLT).

On the right, in the east, the Moon rises over the mountains, while the setting Sun is visible on the left of the panorama, sinking in the west below the clouds over the Pacific Ocean. Its last rays illuminate the four giant VLT Unit Telescope buildings, the smaller VLT Survey Telescope building, the four round VLT Auxiliary Telescope enclosures, and the Paranal staff who have stepped out onto the mountaintop to watch the sunset and the moonrise.

The coincidence of a full Moon and perigee was a treat for observers. The Moon was about 30 000 km closer to us than average. So, the Moon looked about 14% bigger and 30% brighter than when at its most distant. Contrary to various reports, these "supermoons" have no significant effect on earthquakes or volcanoes, and there is no increased risk of natural disasters.

Although its closest approach to Earth in almost two decades gave observers a great photo opportunity, the Moon was still about 357 000 km away and remained far out of reach, even if one were standing on the 2600-metre mountaintop of Paranal. Luckily, we also have advanced astronomical telescopes such as the VLT, whose superb vision seems to bring even more distant astronomical objects within our grasp!

Links

• More about ESO's Photo Ambassadors
• NASA Science News page "Super Full Moon"
• More information about supermoons
• Pictures of the 19 March 2011 supermoon

The number of antennas for the Atacama Large Millimeter/submillimeter Array (ALMA) on the Chajnantor plateau has now reached double digits! The tenth antenna was moved up from the Operations Support Facility at an altitude of 2900 metres to the Array Operations Site at 5000 metres, high in the Chilean Andes, on 4 March 2011 using one of the ALMA transporter vehicles.

ALMA is a telescope designed to observe millimetre- and submillimetre-wavelength light with its array of antenna dishes. Using a technique called interferometry, ALMA acts like a single giant telescope as large as the whole set of antennas. Thanks to the transporter vehicles, the antennas can be arranged in different configurations, where the maximum separation between them varies from 150 metres to 16 kilometres.

The distant viewpoint of this photograph is necessary for one to see all ten of the antennas in a single shot. Nine of them, including the newest addition, are clustered together on the left of the image, but the tenth is about 600 metres away on the right. ALMA is currently in a testing phase, and this lone antenna allows the astronomers and engineers to test the system’s performance with a longer baseline — the separation between a pair of antennas. When ALMA construction is completed in 2013, there will be a total of 66 antennas in the array.

The rare cloudy sky seen in the photograph is due to the Altiplanic Winter, in which the jet stream reverses and brings moist air from the east to this usually extremely arid site.

The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA.

Links

• About ALMA at ESO
• Joint ALMA Observatory website

The Atacama Large Millimeter/submillimeter Array (ALMA) antennas may look rooted to the ground in this striking image — taken at the Array Operations Site on the Chajnantor plateau, at an altitude of 5000 metres — but these dishes are surprisingly mobile.

Thanks to the two antenna transporter vehicles, the antennas in the array — which will consist of a total of 66 dishes when construction is complete — can be repositioned to meet the needs of a particular observation project. The transporters, named Otto and Lore, were specially designed to transport the hefty 115-tonne antennas and position them precisely on concrete foundation pads, spread across the plateau over distances of up to 16 kilometres. Here, four antennas have been placed on closely spaced pads for testing during the Commissioning and Science Verification phase of ALMA construction.

The transporter vehicles drive on 28 tyres, with two 700-HP (500 kW) diesel engines and two 1500-litre fuel tanks, and have a top speed of 12km/h when carrying their precious cargo.

The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA.

ALMA antennas stand side by side, built strong to withstand the unforgiving environment of the Chajnantor plateau, high in the Chilean Andes. At an altitude of 5000 m, the ALMA dishes — a total of 66 when construction is completed — will face strong winds and harsh sunlight, all without the safe haven of a protective dome. The temperature can vary by 40 degrees Celsius, dipping well below freezing and occasionally allowing snow to fall, as can be seen dusting the landscape in the background of this photograph.

The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA.

This photograph was taken by ESO Photo Ambassador José Francisco Salgado.

Links

• ESO Photo Ambassadors webpage.

Four antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) gaze up at the star-filled night sky, in anticipation of the work that lies ahead. The Moon lights the scene on the right, while the band of the Milky Way stretches across the upper left.

ALMA is being constructed at an altitude of 5000 m on the Chajnantor plateau in the Atacama Desert in Chile. This is one of the driest places on Earth and this dryness, combined with the thin atmosphere at high altitude, offers superb conditions for observing the Universe at millimetre and submillimetre wavelengths. At these long wavelengths, astronomers can probe, for example, molecular clouds, which are dense regions of gas and dust where new stars are born when a cloud collapses under its own gravity. Currently, the Universe remains relatively unexplored at submillimetre wavelengths, so astronomers expect to uncover many new secrets about star formation, as well as the origins of galaxies and planets, when ALMA is operational.

The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile.

This picture was taken by ESO Photo Ambassador José Francisco Salgado.

Links

• ESO Photo Ambassadors webpage.

This rich scattering of galaxies was captured using the Wide Field Imager attached to the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. The thousands of galaxies contained in this small area of sky give a glimpse into the Universe’s distant past, whilst also acting as a powerful reminder of the immense scale of the cosmos.

This image was taken as part of the COMBO-17 project (Classifying Objects by Medium-Band Observations in 17 Filters), in which detailed surveys of five small patches of sky were made through 17 different coloured filters. The area of sky covered by each of the five regions is about the same area as that covered by the full Moon. The survey has produced a remarkable haul of celestial specimens. For example, across just three of these regions over 25 000 galaxies have been identified.

Just below the bright stars in the centre of the image is the galaxy cluster Abell 226. It was first noted by astronomer George Ogden Abell in his catalogue of galaxy clusters of 1958. The galaxies in Abell’s clusters, including Abell 226, are only up to a few billion light-years away. But behind these objects, even fainter, more distant galaxies were hiding.

The COMBO-17 study has unveiled these hidden galaxies, thanks to long exposure images from the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. Some of the most distant flecks of light visible in this photo represent galaxies whose light has been travelling towards us for about nine or ten billion years. That means that the galaxies in this image have a great variety of ages, some of them are quite similar to the Milky Way, while others reveal what the Universe was like when it was much younger.

This image was taken using three of the 17 filters from the study: B (in blue), V (in green), and R (in red).

Links

• COMBO-17 at the Max Planck Institute for Astronomy

The HAWK-I instrument on ESO's Very Large Telescope (VLT) at the Paranal Observatory in Chile has been used to great effect in producing this distinctive image of the distant galaxy NGC 157. Boasting a central sweep of stars resembling a giant "S", reminiscent of the comic book hero Superman’s symbol, this celestial spiral is indeed a super example of how new technology is helping us to learn more about the cosmos.

HAWK-I stands for High-Acuity Wide-field K-band Imager, and it is one of the latest and most powerful instruments on the VLT. It detects infrared light, allowing us to peer through the gas and dust that normally obscures our view. This reveals an otherwise hidden view of the Universe, and gives astronomers the opportunity to study dense areas of star formation.

Learning more about star formation is an important step towards expanding our understanding of our own origins. The same processes that are coalescing material in NGC 157 and creating stars there took place around 4.5 billion years ago in the Milky Way to form our own star, the Sun.

NGC 157 is faint at about magnitude 11, but can be tracked down by dedicated amateur astronomers. It is located within the constellation of Cetus (the Sea Monster).

What looks like a barren and inhospitable alien landscape in this 360-degree panorama is in fact the site for ESO’s European Extremely Large Telescope, or E-ELT for short. When construction begins the uninhabited mountaintop left of the centre will become a hive of activity as engineers, technicians and scientists work on building the world’s biggest eye on the sky.

In many ways Chile’s Cerro Armazones may seem like an alien world. The environment is harsh, with low humidity and air pressure, a blazing Sun during the day, but breathtaking skies at night. Cerro Armazones is in the Atacama Desert — one of the driest places on Earth. These conditions, combined with its remoteness, are what make the region such an excellent location for telescopes. Armazones is an isolated peak, 3060 metres above sea level. It is about 20 km away from Cerro Paranal, home of ESO's famous Very Large Telescope. Both summits enjoy crisp skies far away from sources of light pollution.

Among the ELT’s many science goals is a particularly hot topic in contemporary astronomy: the quest for exoplanets. The E-ELT will search for Earth-like planets orbiting other stars and could even directly image larger planets or probe their atmospheres. The E-ELT’s high-tech instruments will also study the formation of planets in protoplanetary discs around young stars. Detecting water and organic molecules will shed light on how planetary systems are produced, and could bring us one step closer to answering the question of whether we are alone in the Universe.

This panorama was taken by ESO Photo Ambassador Serge Brunier.

Links

• See more stunning panoramas of ESO sites in our virtual tours.
• ESO Photo Ambassadors webpage.

As the Sun sets over Cerro Armazones, plans are well advanced for building the world's biggest “eye on the sky”: ESO's European Extremely Large Telescope (E-ELT). With a primary mirror 39 metres in diameter, the E-ELT will dwarf all existing visible-light telescopes.

Site selection has been a vital part of the plans for the E-ELT. Over the course of several years a team of experts investigated locations around the world, looking for the best place to host such an ambitious project. The site for the E-ELT must be remote enough not to be influenced by problems such as light pollution, but also needs the necessary infrastructure for the construction and operation of the observatory, and to accommodate the over 150 staff who will eventually work there. Monitoring stations, such as the one shown here, were set up to test site conditions scientifically by measuring parameters that included atmospheric turbulence and levels of water vapour. By better understanding the atmosphere at a site, the team were able to determine the best potential site for the highest quality science.

The list of potential sites included areas in Argentina, in Chile, in Morocco and in Spain. Cerro Armazones in Chile, shown in this photograph, was finally selected as the E-ELT site because it has the best balance of sky quality across all aspects and it can be operated in an integrated fashion with the existing ESO Paranal Observatory nearby. Armazones is about 20 km from Paranal and 130 km south of the nearest town. It is 3060 metres above sea level and boasts almost 350 cloudless nights a year.

Constructing the E-ELT is a huge undertaking that will take several years. The go-ahead for construction is planned for 2011, with start of operations planned for early in the next decade. When observations begin, the E-ELT will herald a new era for astronomy.

Like the bow of a ship sailing a rolling ocean of red hills, the southeast corner of the observing platform at Paranal stands over the Mars-like landscape of the Chilean Atacama Desert. This panorama shows the breathtaking view of the horizon, and conveys the feeling of immensity experienced when looking from the top of Cerro Paranal, a remote 2600-metre-high mountain located in one of the driest regions on Earth.

Atop Cerro Paranal is the ESO Very Large Telescope (VLT), the world’s most advanced optical and near infrared ground-based astronomical facility, composed of four 8.2-metre Unit Telescopes (UTs) and four 1.8-metre Auxiliary Telescopes (ATs). The fourth Unit Telescope (UT4), named Yepun in the Mapuche language, is most prominent in this photograph, while UT3 (Melipal) and UT1 (Antu) are just visible on the right-hand edge of the picture. Three of the smaller ATs can also be seen on the 200-metre-wide observing platform. The yellow structure in front of Yepun is the “M1 Lifting Platform”, used to move the 8.2-metre-diameter primary mirror (M1) and its support structure out of the telescope building for periodic recoating.

In the distance, over the edge of the platform, is the Paranal Observatory base camp, which includes the Residencia, the Main Maintenance Building, the power station and the warehouse. These facilities are situated some 2 km away from the telescopes, at a lower altitude of about 2400 metres. The whole observatory complex operates as an “island” in the desert, where essentials such as water, food and fuel must be brought from Antofagasta, located about 120 km to the north. The remoteness of the site makes operating Paranal Observatory a great logistical challenge, but the reward is a location with superb conditions for astronomy.

Before another clear, starry night falls at ESO's Paranal Observatory, home of the Very Large Telescope (VLT), the sky produces a palette of intense colours, putting on a beautiful show for observers. These colours can only be seen with such depth from sites such as Paranal, where the atmosphere is extraordinarily pure. Looking to the west, over the Pacific Ocean, the sunset sky turns bright orange and red. However, this photograph shows the view to the east instead, looking away from the Sun after it has just set. The grey-bluish shadow above the horizon is the shadow of our own planet. Above this is a pinkish glow known as the "Belt of Venus", a phenomenon produced by the reddened light of the setting Sun being backscattered by the Earth's atmosphere.

In the centre of the image is the fourth 8.2-metre Unit Telescope (UT4), part of the VLT. The Mapuche name given to UT4 is Yepun, which means Venus. As well as working as individual telescopes, groups of two or three UTs can combine their light using a technique called interferometry, which allows astronomers to see details up to 25 times finer than with the individual telescopes. The VLT also has four 1.8-metre Auxiliary Telescopes (ATs), housed in ultra-compact mobile enclosures, which are fully dedicated to interferometric observations. Two of the ATs are visible in the background, with a third mostly hidden.

The yellow frame-like structure in front of Yepun is the "M1 Lifting Platform", used when the giant 8.2-metre primary mirror (M1) of the telescope is periodically recoated. The delicate mirror and its support structure, which together weigh 45 tonnes, are removed from the telescope enclosure and slowly driven about two kilometres to a maintenance building at the Paranal base camp. This process is, unsurprisingly, performed with the utmost care.

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Rolling red hills stretch out below the exceptionally clear blue sky that is typical of ESO's Paranal Observatory. Although the telescope domes close at dawn, and nothing seems to move on the surface of this barren desert, the ESO Very Large Telescope (VLT) never rests. Since early morning, a team of engineers and technicians has been working hard to prepare the telescopes and instruments for another "perfect night".

The 2600-metre-high Cerro Paranal stands out at the centre of this panoramic view, taken looking towards the south. This flattened mountaintop is home to the VLT, the world's most advanced ground-based optical and near infrared astronomical facility. The VLT has four 8.2-metre Unit Telescopes (UTs), plus four 1.8-metre Auxiliary Telescopes (ATs). In this picture, only two of the UT enclosures, together with the smaller 2.6-metre VLT Survey Telescope (VST) are visible.

To the right of Cerro Paranal, the sea of clouds that typically covers the coast of the Pacific Ocean — only 12 km away — is visible in the background. The cold oceanic stream typically keeps the thermal inversion layer of the atmosphere below an altitude of 1500 metres, making this remote area of the Chilean Atacama Desert in the II Region of Chile one of the driest sites on Earth and a perfect window on the Universe. The atmosphere here is extremely dry and clear, and has very low turbulence, offering the most suitable conditions for optical and near-infrared astronomical observations.

For this reason, the 3060-metre-high Cerro Armazones, located just some 20 km east of Paranal, was selected as the site for the future European Extremely Large Telescope (E-ELT). With a primary mirror 39 metres in diameter, the E-ELT will be the world's largest eye on the sky.

This photograph was taken from a neighbouring mountain, home of the 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA). VISTA started operations at the end of 2009 and is the most recent telescope to be added to the roster at ESO's Paranal Observatory. VISTA is the largest survey telescope in the world.

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This splendid picture shows the European Southern Observatory's Very Large Telescope (VLT) on Cerro Paranal in the Chilean Atacama desert. The mountaintop, 120 km south of the town of Antofagasta, is a remote haven for scientific exploration.

Its distance from populated areas means that light pollution is essentially non-existent, which helps to guarantee clear views for the telescopes. It also ensures that activity is not disturbed by other human activities, such as traffic on nearby roads or dusty air from mines. The desert location means that moisture in the atmosphere is at a very low level, which contributes to the excellent atmospheric conditions. As well as the VLT, Paranal Observatory is also home to the VISTA telescope on an adjacent peak, from which this photograph was taken. The road which links the two peaks can be seen in the centre of the image, winding through the desert landscape.

The two distinct bright patches seen here in the night sky are the Large and Small Magellanic clouds, which are neighbouring galaxies to the Milky Way, about 160 000 and 200 000 light-years away respectively. The path of the Milky Way itself can be seen on the left of the image. Astronomers use the VLT to study our own galaxy, the neighbouring Magellanic Clouds, and naturally also much more distant galaxies billions of light-years from Earth. On the long and winding road to the stars, observatories like the VLT are our first steps.

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On a remote mountaintop, 2600 metres above sea level in the Chilean Atacama Desert, lies the world’s most advanced visible-light observatory. The European Southern Observatory’s Very Large Telescope (VLT) is not only a window on the Universe; it is also a celebration of modern science and technology.

This photograph shows two of the four Unit Telescopes that make up the VLT. With its giant 8.2-metre diameter mirrors, sensitive detectors, and state-of-the art adaptive optics system, the VLT uses cutting-edge technology at every opportunity. Even the telescope enclosures — the domes — are highly advanced, being thermally controlled to reduce air turbulence in the telescope structure.

Every night the VLT studies the sky to make discoveries about the Universe. Visible in this photo, sweeping between the two Unit Telescopes, is the plane of the Milky Way. Containing billions of stars, it is our own corner of the cosmos, but the VLT's vision can peer much deeper than this, our home galaxy, and look out to the extremes of space, all in the name of science and discovery.

This image is available as a mounted image in the ESOshop.

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As soon as the Sun sets over the Chilean Atacama Desert, ESO’s Very Large Telescope (VLT) begins catching light from the far reaches of the Universe. The VLT has four 8.2-metre Unit Telescopes such as the one shown in the photograph. Many of the photons — particles of light — that are collected have travelled through space for billions of years before reaching the telescope’s primary mirror. The giant mirror acts like a high-tech “light bucket”, gathering as many photons as possible and sending them to sensitive detectors. Careful analysis of the data from these instruments allows astronomers to unravel the mysteries of the cosmos.

The telescopes have a variety of instruments, which allow them to observe in a range of wavelengths from near-ultraviolet to mid-infrared. The VLT also boasts advanced adaptive optics systems, which counteract the blurring effects of the Earth's atmosphere, producing images so sharp that they could almost have been taken in space.

This image is available as a mounted image in the ESOshop.

Imagine being a fly on the wall of ESO's Very Large Telescope (VLT) at the world's most advanced optical observatory. You could have a view a little like this. Fisheye photography gives this unusual view of the 8.2-metre diameter telescope, poised and ready to begin gathering light from the deep recesses of the Universe as soon as the dome opens and starlight pours in.

The VLT has four of these 8.2-metre Unit Telescopes, called Antu, Kueyen, Melipal and Yepun. These are the Mapuche names for the Sun, Moon, Southern Cross and Venus. This photograph shows Yepun. The names are from the native language of the indigenous people who live mostly in the area south of the Bio-Bio River, some 500 km south of Santiago de Chile.

The VLT is so powerful that it allows us to see objects four thousand million times fainter than those that can be seen with the unaided eye. This has helped make ESO the most productive ground-based observatory in the world.

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• More information about the names of the VLT Unit Telescopes
• Take a Virtual Tour of the VLT

NGC 520 — also known as Arp 157 — looks like a galaxy in the midst of exploding. In reality, it’s the exact opposite. Two enormous spiral galaxies are crashing into each other, melding and forming a new conglomerate. This happens slowly, over millions of years — the whole process started some 300 million years ago. The object, about 100 000 light-years across, is now in the middle stage of the merging process, as the two nuclei haven’t merged yet, but the two discs have. The merger features a tail of stars and a prominent dust lane. NGC 520 is one of the brightest interacting galaxies in the sky and lies in the direction of Pisces (the Fish), approximately 100 million light-years from Earth.

This image was taken by the ESO Faint Object Spectrograph and Camera attached to the 3.6-metre telescope at La Silla in Chile. It is based on data obtained through B, V, R and H-alpha filters.

The centre of our own galaxy, the Milky Way, is again in the sights of ESO telescopes. This time it’s the turn of ISAAC, the VLT’s near- and mid-infrared spectrometer and camera.

From Chile’s Atacama Desert, site of the ESO observatories, the Milky Way offers magnificent views, particularly in the southern hemisphere winter, when the central region of our galaxy is most visible (see eso0934). However, the Galactic Centre itself, located about  27 000 light-years away in the constellation of Sagittarius, hides behind thick clouds of interstellar dust, which appear as dark obscuring lanes in visible light, but which are transparent at longer wavelengths such as the infrared. In this image, the infrared observations clearly reveal the dense clustering of stars in the galactic core.

ESO telescopes have been tracking stars orbiting the centre of the Milky Way for more than 18 years, getting the highest resolution images of this area and providing a definitive proof of the existence of a supermassive black hole in the heart of our galaxy (read more in eso0226 and eso0846). Infrared flashes emitted by hot gas falling into the supermassive black hole have also been detected with ESO telescopes (see eso0330).

This representative-colour picture is composed of images taken by ISAAC at near-infrared wavelengths through 2.25, 2.09, and 1.71 µm narrowband filters (shown in red, green and blue respectively). It covers a field of view of 2.5 arcminutes.