A rare patch of wispy white clouds streak across the sky over ESO’s La Silla Observatory in this photograph, taken on 11 June 2012 by astronomer Alan Fitzsimmons.
This dry, desolate environment with occasional strong gusts of wind may not be the best place for people to set up home, but it is the ideal location for telescopes. Dry, arid conditions help astronomers to avoid common observing problems like atmospheric disturbance, light pollution, humidity, and (most of the time!) clouds, allowing them to gain a clearer view of the cosmos above. Even on this rare day of cloud the sky had cleared by nightfall and observations took place as usual.
The telescopes that call La Silla home — including two major ESO-operated telescopes: the ESO 3.6-metre telescope and the New Technology Telescope (NTT) — are equipped with state of the art instruments, enabling them to fully exploit the unique viewing conditions in northern Chile.
The ESO 3.6-metre telescope currently operates with the High Accuracy Radial velocity Planet Searcher (HARPS), an instrument that is dedicated to the discovery of extrasolar worlds. The NTT was a pioneer in active optics, and was the first telescope in the world to have a computer-controlled main mirror.
La Silla was the first ESO site to be based in Chile back in the 1960s, and has been invaluable ever since.
At present ESO hosts three observatories in the Atacama Desert region of Chile: La Silla, Paranal and Chajnantor. Visible in the background of this image is Paranal, ESO’s flagship facility and home of the Very Large Telescope (VLT) array.
In coming years, this trio will be joined by a fourth observatory: Cerro Armazones, future site of the European Extremely Large Telescope (E-ELT). With its 39-metre-diameter mirror, the E-ELT will be the world’s biggest eye on the sky when construction is completed around 2024.
Cerro Armazones is currently only linked to Paranal by a dirt track — but, as shown in this image, construction is underway. The Chilean company ICAFAL Ingeniería y Construcción S.A. (ICAFAL) began construction in March (ann14019), and is due to take around 16 months to complete a new 7-metre-wide asphalt road. As well as carving a new road through the Chilean landscape, ICAFAL will level off the top of Cerro Armazones to create a usable platform for the E-ELT.
At 5000 metres above sea level, high upon the Chajnantor Plateau in Chile, the antennas of the ALMA Observatory peer skywards, scanning the Universe for clues to our cosmic origins. This plateau is one of the highest observatory sites on Earth.
Visible amongst the thousands of stars on the right side of this image are the Small and Large Magellanic Clouds, appearing as luminous smudges in the sky. These cloud-like objects are both galaxies — two of the closest galactic neighbours to our galaxy, the Milky Way.
ALMA's main aim is to observe the coldest and most ancient objects in the cosmos — known as the "cold Universe". The array measures radiation emitted in the millimetre and submillimetre wavelengths, which lie in between infrared and radio waves in the electromagnetic spectrum. It features 66 mobile antennas which can be moved and configured over the ALMA site to meet the scientists' requirements, making it the biggest astronomical experiment in existence.
This amazing picture of the ALMA landscape was taken by ESO Photo Ambassador Stéphane Guisard, an optics engineer at the European Southern Observatory's Very Large Telescope in the Atacama Desert, Chile.
Close to ESO's ALMA Observatory, a tour bus creates a cloud of dust as it makes its way across the Chilean desert. This bus carries staff heading to the ALMA Operations Support Facility for the start of an 8-day shift. In the background we see two volcanoes, their snow-covered peaks obscured by clouds.
Located on the border between Bolivia and Chile, these two inactive volcanoes, despite being just a short distance from each other, were created in different geological epochs — Licancabur, the volcano on the left, is much younger than its smaller neighbour Juriques.
Licancabur is famous for its near-symmetrical shape, and for being home to one of the highest lakes in the world. At an altitude of 5916 metres, the lake in Licancabur’s caldera is host to a variety of rare flora and fauna, and has been studied to see how life is coping in this extreme environment. It is said that the Licancabur region is one of the best analogues for the Martian environment, and that by studying the life present here, we may better understand how life could flourish on other planets.
This image was taken by ESO's Armin Silber.
This panoramic view of ESO’s flagship facility in northern Chile was taken by ESO Photo Ambassador Gabriel Brammer. The Very Large Telescope (VLT) is seen setting to work at ESO’s Paranal Observatory, visible against a backdrop of clear skies with the Milky Way overhead.
To create this picture, Brammer combined several long-exposure shots in order to capture the faint light of the Milky Way as it circled above the massive enclosures of the VLT’s Unit Telescopes. Each of these giants is 25 metres tall, and they are named after prominent features of the sky in the language of the local Mapuche tribe: the Sun, the Moon, the constellation of the Southern Cross, and Venus — Antu, Kueyen, Melipal, and Yepun respectively. On the left of the frame, the smaller Auxiliary Telescopes can be seen in their white round, domes, with the large and small Magellanic Clouds above them.
The combination of several shots reveals the movement of the telescope enclosures, each accompanied by a ghostly echo of themselves as they move during the night following their targets in the sky. The passage of time is also evident, with a bright evening sky giving way to a dark, star-speckled view towards the left of the image.
To create this image, Brammer set up his camera at the same position twice: once at sunset, and then again later at night. Using the images taken at these different times, Brammer created two complete panoramas that he later composited to form the image shown here.
Can you count the number of bright dots in this picture? This crowded frame is a deep-field image obtained using the Wide Field Imager (WFI), a camera mounted on a relatively modestly sized telescope, the MPG/ESO 2.2-metre located at the La Silla Observatory, Chile.
This image is one of five patches of sky covered by the COMBO-17 survey (Classifying Objects by Medium-Band Observations in 17 filters), a deep search for cosmic objects in a relatively narrow area of the southern hemisphere's sky. Each one of the five patches is recorded using 17 individual colour filters. Each one of the five COMBO-17 images covers an area of the sky the size of the full Moon.
The survey has already revealed thousands of previously unknown cosmic specimens — over 25 000 galaxies, tens of thousands of distant stars and quasars previously hidden from our view, showing just how much we still have to learn about the Universe.
Some of the most distant flecks of light visible in this photo are galaxies whose light has been travelling for nine or ten billion years before reaching to us. By studying galaxies of different ages astronomers can understand how they evolve in time, from mature nearby galaxies similar to our galaxy, the Milky Way, to young ones in the distant Universe that reveal what the cosmos was like in its infancy.
This aerial photograph shows the sprawling site of the European Southern Observatory’s (ESO) Headquarters in Garching bei München, Germany. While ESO operates telescopes scattered across Chile in the southern hemisphere, Garching houses the scientific, technical and administrative centre of ESO, where development programmes are carried out to provide the observatories with the most advanced instruments.
The buildings in the centre of the frame, both with sleek, curved designs, are the two main ESO Headquarters buildings — the top-right building was the organisation’s sole base for many years before it was recently joined by the lower red-roofed extension, which was inaugurated in December 2013. The black, rounded building is the technical building, where work on new instruments is carried out. Each of the individual Headquarters buildings are connected by curved bridges, seen here as the three-armed black shape in the centre of the frame.
The new extension, designed by architects Auer+Weber, now helps to house ESO’s growing numbers of staff and to facilitate world-class astronomical research in the design and construction phase of the European Extremely Large Telescope (E-ELT), the world’s biggest eye on the sky. Previously, some members of staff were spread across the Garching campus and housed in buildings similar to the white blocks seen to the left of this image.
This aerial image was taken on 9 June 2014 by aerial photographer Ernst Graf (graf-flugplatz.de).
The Sun sets over Paranal Observatory, painting an array of subtle hues across the sky reminiscent of a Monet landscape. The sparse clouds glow warmly under the Sun's last rays, and the crisp clarity of the air is almost palpable — highlighting why ESO has selected this area of Chile for its observatory. Crepuscular rays — and shadows from the clouds — are streaming from the Sun and appear to converge at the antisolar point.
Two of the four domed Auxiliary Telescopes (ATs) of the Very Large Telescope (VLT) can be seen on the left, waiting patiently for darkness to fall before conducting their survey of the cosmos.
Once the Sun has set, the 1.8-metre diameter ATs will feed starlight to the Very Large Telescope Interferometer (VLTI), combining the light to produce clear images of the Universe. The mobile ATs are mounted on rails, and can be moved around the VLT site to view the skies from different angles.
This image was posted to the Your ESO Pictures Flickr group by Roger Wesson, a fellow at ESO working at the Paranal Observatory, on 8 March 2013.
This new image, taken by ESO Photo Ambassador Gianluca Lombardi, shows a stunning array of colours, ranging from the haze of pink dominating the bottom of the frame to the blues and whites of the Milky Way above. The blocks visible at the foreground of the image are the Unit Telescopes of the Very Large Telescope (VLT), based at ESO's Paranal Observatory in Chile.
Cutting through the scene is a harsh yellow slash. This prominent streak is the VLT's laser guide star, which is part of the telescope's adaptive optics system that compensates for the blurring effects of the atmosphere. Light from the sky is distorted as it travels through the atmosphere due to local variations. Whenever possible, astronomers hunt down a bright star to calibrate their observations, but when there is no suitable star near enough to their target, they have to rely on an artificial one — created by pointing a bright, piercing laser up into the night, as shown in this image.
This new image shows the construction progress of the road, platform, and service trench at the site of the future European Extremely Large Telescope (E-ELT) on Cerro Armazones. The basecamp can be seen to the lower right and the new road is seen curving around the base of the mountain.
The Chilean company ICAFAL Ingeniería y Construcción S.A. started the civil works for the E-ELT in March 2014 when they began construction of a road to the summit of the mountain. The construction is expected to take 16 months to complete. The road will provide access for the future construction of the giant telescope, and will be 11 metres wide, with an asphalt paved driveway 7 metres wide.
Construction worker for the company, Sebastián Rivera Aguila, caught this sight on Thursday 12 June 2014 from a commercial airplane flying over the mountain. He expressed his excitement: "It is really hard work to build in the desert, but I am really proud and very happy to be part of this very important project. Thank you to ICAFAL and ESO for letting us be part of history in the making."
On Thursday 19 June, ICAFAL will blast the area on the top of Cerro Armazones, loosening about 5000 tonnes of rock. This is part a large-scale levelling process which will help landscape the mountain so that it can accommodate the 39-metre telescope and the associated buildings at the observatory. A groundbreaking ceremony will take place at Paranal Observatory, 20 kilometres away from the blasting, to mark this milestone towards the construction of the E-ELT. The event will be streamed live via webcast on Livestream from 16:30 UTC until around 18:30 UTC (18:30-20:30 CEST) (subject to change). Participants can also follow the live tweeting from @ESO under the hashtag #EELTblast and ask questions, in English, which we will try as far as possible to answer in real time.
This image shows the beginning of sunrise over the Very Large Telescope (VLT) at ESO's Paranal Observatory in Chile. In this photo, one of the VLT's Unit Telescopes is visible to the bottom right, illuminated by moonlight. Further in the distance there are two Auxiliary Telescopes pointing upwards.
The VLT is formed of four 8.2-metre Unit Telescopes (UTs), and four movable 1.8-metre Auxiliary Telescopes (ATs). The telescopes can work together to form a giant interferometer: the Very Large Telescope Interferometer (VLTI). The light collected by each of these telescopes is combined by the VLTI using a complex system of mirrors in underground tunnels, allowing astronomers to see details up to 16 times finer than with the individual UTs alone.
The image was taken by Nicolas Blind, an astronomer who visited Paranal Observatory for a few days in December 2012. Blind may only have been at the observatory for a short period, but he had a truly memorable visit. "The absolute silence in this place is so peaceful and relaxing," he recalls. "You can only hear the sound of wind, or maybe a bat lost in this desolated area. The pure sky of Paranal reminds me each time how little we are, and reconnects me with the reason why I have chosen astronomy."
Paranal Observatory experiences an incredible 330 clear nights per year. In fact, thanks to the technology, staff, and clear conditions, the VLT is the most productive individual ground-based facility in the world.
Nicolas Blind 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.
Framed by the glow of the Moon setting, the fourth Unit Telescope (UT4) of ESO's Very Large Telescope (VLT) at Paranal Observatory is enveloped by the sky it studies night after night.
Located high on Cerro Paranal, the majestic machine sits gracefully at an altitude of 2635 metres above sea level. Paranal is the world's most advanced visible-light astronomical observatory and ESO’s flagship facility, containing a suite of telescopes.
UT4, otherwise known as Yepun (Venus), is one of the four Unit Telescopes that comprise the VLT, also working with their four Auxiliary Telescope companions to form the super-sensitive Very Large Telescope Interferometer (VLTI). Housed within a thermally controlled building, UT4 uses its incredibly precise 8.2-metre mirror to scan the stars and unravel the mysteries of the Universe.
The other three Unit Telescopes are known as Antu (Sun), Kueyen (Moon), and Melipal (Southern Cross), from the language of the Mapuche people from some 500 kilometres south of Santiago.
This image was snapped by photographer John Colosimo, and manages to capture both the beauty and complexity of the lone Unit Telescope.
The sky over Paranal Observatory in northern Chile is a real treat for ESO's Photo Ambassadors, who are constantly experimenting with new techniques to obtain even more striking views of the unique, arid landscape and state-of-the-art facilities.
On this occasion, Gianluca Lombardi has combined many long-exposure images to get this stunning result — the Very Large Telescope (VLT) and its Auxiliary Telescopes, their motion appearing as blurred flickers beneath a stream of stars, while the apparent motion of the stars across the sky has left smeared trails that are captured on camera as the Earth rotates.
The VLT is ESO's flagship facility. It is of the most productive telescopes in the world, and the most advanced optical instrument ever made.
A small crowd gathers by the telescopes to see the night in at ESO’s Paranal Observatory in Chile. For most, sunset marks the end of a working day — a time for rest. But not here; nighttime is when the real work is done, with a clear night’s sky as the workplace.
The crowd looks tiny, dwarfed by the telescopes to their left. These domes house the four 1.8-metre-diameter Auxiliary Telescopes that are part of the Very Large Telescope array (VLT). But the real giant of the picture is at the far left; if the Auxiliary Telescopes make the crowd look small, then the VLT Unit Telescope makes them look like ants. The VLT has four 8.2-metre telescopes like this, some of the largest telescopes on the planet.
But if you think that’s big, wait for the European Extremely Large Telescope (E-ELT), set for first light in the early 2020s. Its mirror will be a whopping 39 metres in diameter! As we look to the future, ESO will be bringing the world bigger and better eyes on the sky.
This gorgeous photograph, taken in the Atacama Desert in Chile, shows star trails circling the South Celestial Pole, over a cacti-dominated still landscape. The star trails show the apparent path of the stars in the sky as the Earth slowly rotates, and are captured by taking long-exposure shots.
A final deeper exposure was superimposed over the magnificent trails, revealing many more, fainter stars and, just rising above the horizon, the southern Milky Way, with its patches of dark dust and the well-known pinkish glow of the Carina Nebula. Towards the right, the satellite galaxies of the Milky Way, the Large (top-centre) and Small (bottom-right) Magellanic Clouds, can also be seen.
The Sun sets over La Silla, one of ESO's observing sites in Chile, creating a fiery orange glow along the horizon.
This image, taken by David Jones, shows the alignment of three planets over the summit of ESO's telescopes in June 2013. Here the trio visible to the left of centre is composed of Jupiter (bottom left, almost invisible in orange sunset), Venus (centre), and Mercury (top right) — see labelled image.
Alignments like this happen only once every several years, so it is a real treat for photographers and astronomers. When three (or more) celestial objects align like this in the sky, it is called a "syzygy". Check this syzygy image, showing almost the same scene (also from May 2013).
"This image was taken during a five-night observing run with the 3.6-metre New Technology Telescope on La Silla, so I was very fortunate to be awarded observing time at just the right time to take the picture," adds photographer Dave Jones. "The close clustering of the three planets only lasted a week or so, and the next time something like this will come around will be 2026, so it’s a very lucky snap indeed!"
Based at one of the driest places on Earth on the outskirts of the Atacama Desert in Chile, atmospheric conditions are so stable here they provide crystal-clear views of our night sky. This image is actually a blend of two photos of different exposure lengths, producing a detailed view of the observing site as the Sun begins to set.
This image shows an ancient sun-scorched boulder near ESO's La Silla Observatory in Chile, on the outskirts of this desert at a height of some 2400 metres above sea level.
Visible on the boulder are several petroglyphs — rock engravings — depicting men and llamas. Llamas have historically been very important to South American cultures, being used as both a source of food and wool, and also as a pack animal for carrying goods across the land. The importance of llamas was reflected in the beliefs of the pre-Columbian people who inhabited the region — the Inca herders worshipped a multicoloured llama deity by the name of Urcuchillay, who was said to watch over the animals. The name Urcuchillay was also given to the constellation of Lyra (The Lyre) by the ancient Inca astronomers.
The llama is honoured yet again in the Inca constellations. These constellations were formed from dark patches on the bright plane of the Milky Way, rather than from bright, prominent stars — as is the Western tradition. One of these dark constellations was known as Yacana (The Llama), which stretches from the galactic centre towards the Southern Cross, its eye being our stellar neighbour Alpha Centauri.
This image was taken by Håkon Dahle, an accomplished professional astronomer. He 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.
Many hands make light work, as the old saying goes, although perhaps in this case the phrase "many wheels make light work" is more appropriate. Pictured here is Otto, one of the two ALMA Transporters along with its companion Lore. Otto and Lore were responsible for carrying the ALMA antennas up to the Chajnantor Plateau, a site some 5000 metres above sea level in northern Chile. After placing the antennas, the two trucks have the additional task of repositioning them according to the scientists' requirements. Otto can be seen in action in this video.
These two powerful beasts are the ultimate in custom vehicles. They were designed specifically for ESO by the German vehicle manufacturer Scheuerle Fahrzeugfabrik, who have an impressive history of transporting heavy loads like the Antares rocket and an oil platform weighing in at a staggering 15 000 tonnes!
The transporters are identical except for the colour of the safety rails on the vehicle. Otto has red rails, as seen in the picture, and Lore can be identified by a set of green rails. Each individual truck is powered by two diesel engines each with a power output of 700 horsepower, totalling 1400 horsepower per vehicle. Both trucks can also be controlled remotely, allowing operators a clear view when positioning the antennas with millimetre accuracy.
The ALMA transporters are such an integral part of the ALMA facility that they can almost be considered as part of the telescope. Without the two vehicles, the construction, operation, and maintenance of the array would not be possible.
This image was taken by José Velásquez.
A curtain of stars surrounds the 3.58-metre New Technology Telescope (NTT) in this new Ultra High Definition photograph from the ESO Ultra HD Expedition . It was captured on the first night of shooting at ESO's La Silla Observatory, which sits at 2400 metres above sea level on the outskirts of the Chilean Atacama Desert.
The majestic telescope enclosure aligns perfectly with the Milky Way’s central region — the brightest section and the area which obscures the galactic centre. The distinctive octagonal enclosure that houses the NTT stands tall in this image — silhouetted against the glittering cosmos above and almost appearing to consume the Milky Way. This telescope housing was considered a technological breakthrough when completed in 1989.
Visible to the left of the Milky Way is the bright orange star Antares at the heart of Scorpius (The Scorpion). Saturn can be seen as the brightest point to the upper left of Antares and Alpha and Beta Centauri glow in the upper right of the image. The Southern Cross (Crux) and the Coalsack dark nebula are also visible looming above Alpha and Beta Centauri.
La Silla was ESO’s first observatory, inaugurated in 1969. The NTT pictured above was the first telescope in the world to have a computer-controlled main mirror and broke new ground for telescope engineering and design paving the way for ESO's Very Large Telescope.
 The team is made up of ESO's videographer Herbert Zodet, and three ESO Photo Ambassadors: Yuri Beletsky, Christoph Malin and Babak Tafreshi. Information on the expedition's technology partners can be found here, and their blog here.
This beautiful new image, taken during a time-lapse set at the Atacama Large Millimeter/submillimeter Array (ALMA) is another dramatic Ultra High Definition photograph from the ESO Ultra HD Expedition. ALMA, located at 5000 metres above sea level on the remote and empty Chajnantor Plateau in the Chilean Andes, marks the second destination for the four ESO Photo Ambassadors  on their 17-day trip. The ambassadors are equipped with state-of-the-art Ultra HD tools to help them capture the true majesty of sights like the one pictured here  .
Some of the 66 high-precision antennas that comprise ALMA are visible here, with dishes pointed aloft, studying the cold clouds in interstellar space, and peering deep into the past at our mysterious cosmic origins.
The spectacular javelin of light over the ALMA array is a shooting star, slicing through the image in a vivid streak of colours. Emerald green, golden and faint crimson hues blaze brightly as the meteor burns up as it enters the Earth’s atmosphere and makes its fiery voyage across the sky. As the high-speed fireball — which is, in reality, a small grain of rock from interplanetary space — interacts with the atmosphere it heats up, vapourising the surface layers of the meteor, which are left behind in a glowing trail. These trails disappear in just a few seconds, but are captured here at the click of a button.
The brightest star in the constellation of Virgo (The Virgin), known as Spica, and our neighbouring planet Mars glow brightly in the centre of the image — cosmic spectators to this fiery descent as they rise above the horizon.
The Ultra HD Expedition began in Santiago, Chile, on 25 March 2014. This image was taken on the team’s eighth night on the Chajnantor Plateau. They are currently at La Silla Observatory, ESO’s first astronomical installation in Chile, and tomorrow, after one last night, they will finally make the long journey home. Free Ultra HD content gained from this expedition will soon be available online as ESO delivers crisp, breathtaking Ultra HD footage — bringing the Universe closer than ever before. This image was taken by ESO Photo Ambassador and time-lapse Cinematographer Christoph Malin.
 The team is made up of ESO’s videographer Herbert Zodet, and three ESO Photo Ambassadors: Yuri Beletsky, Christoph Malin and Babak Tafreshi. Information on the expedition’s technology partners can be found here, and their blog here.
 Equipment includes: Vixen Optics Polarie Star Tracker, Canon® EOS-1D C camera, Stage One Dolly and eMotimo TB3 3-axis motion control camera robot, Angelbird SSD2go, LRTimelapse software. Peli™ Cases, 4K PC workstations from Magic Multimedia, Novoflex QuadroPod system, Intecro batteries and Granite Bay Software.