As the full Moon sets, the Sun is about to rise on the opposite horizon. The ESO's Very Large telescope (VLT) has already closed its eyes after a long night of observations, and telescope operators and astronomers sleep while technicians, engineers and day astronomers wake up for a new day of work. Operations never stop at the most productive astronomical ground-based observatory in the world. ESO staff member Gordon Gillet welcomed the new day by capturing this stunning image from 14 km away, on the road to the nearby Cerro Armazones. #

This view of the Chajnantor Plateau shows the site of the Atacama Large Millimeter/submillimeter Array (ALMA), taken from near the peak of Cerro Chico. Babak Tafreshi, an ESO Photo Ambassador, has succeeded in capturing the feeling of solitude experienced at the ALMA site, 5,000 meters above sea level in the Chilean Andes. When the telescope is completed in 2013, there will be a total of 66 such antennas in the array, operating together. ALMA is already revolutionizing how astronomers study the Universe at millimeter and submillimeter wavelengths. Even with a partial array of antennas, ALMA is more powerful than any previous telescope at these wavelengths, giving astronomers an unprecedented capability to study the cool Universe -- molecular gas and dust as well as the relic radiation of the Big Bang. #

A glowing laser shines forth from the VLT, piercing the dark Chilean skies, its mission is to help astronomers explore the far reaches of the cosmos. 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. While it's a beautiful sight, 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 laser energizes sodium atoms high in the Earth's mesosphere, causing them to glow and creating a bright dot that appears to be a man-made star. Observations of how this "star" twinkles are fed into the VLT'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. #

This color-composite image of the Helix Nebula (NGC 7293) was created from images obtained using the Wide Field Imager (WFI), an astronomical camera attached to the 2.2-meter Max-Planck Society/ESO telescope at the La Silla observatory in Chile. The blue-green glow in the center of the Helix comes from oxygen atoms shining under effects of the intense ultraviolet radiation of the 120 000 degree Celsius central star and the hot gas. Further out from the star and beyond the ring of knots, the red colour from hydrogen and nitrogen is more prominent. A careful look at the central part of this object reveals not only the knots, but also many remote galaxies seen right through the thinly spread glowing gas. #

Many billions of years old, but still sparkling brightly, NGC 2257 is a globular cluster, the name given to the roughly spherical concentrations of stars that orbit galactic cores, but are often found far out from the centers in the halo areas of galaxies. NGC 2257 lies on the outskirts of the Large Magellanic Cloud (LMC), a satellite galaxy of our own Milky Way. The image is made from data taken with the Wide Field Imager instrument on the 2.2-meter MPG/ESO telescope at La Silla, as part of the ESO Imaging Survey project, which was planned to make public imaging surveys to identify targets for follow-up observations with the VLT. #

A view of the Chajnantor plateau, showing the ALMA antennas ranged across the unearthly landscape. Some familiar celestial objects can be seen in the night sky behind them. These crystal-clear night skies explain why Chile is the home of not only ALMA, but also several other astronomical observatories. In the foreground, the 12-meter diameter ALMA antennas are in action, working as one giant telescope. On the far left, a cluster of smaller 7-meter antennas for ALMA's compact array can be seen illuminated. The crescent Moon, although not visible in this image, casts stark shadows over all the antennas. In the sky above the antennas, the most prominent bright "star", on the left of the image, is in fact the planet Jupiter. The Large Magellanic Cloud can also be clearly seen on the right, just above the rightmost antenna. On the far left of the image, just left of the foreground antennas, is the elongated smudge of the Andromeda galaxy. This galaxy, more than ten times further away than the Magellanic Clouds, is our closest major neighboring galaxy. Even though only its most central region is apparent in this image, the galaxy spans the equivalent of six full Moons in the sky. #

The ALMA correlator, one of the most powerful supercomputers in the world, fully installed and tested at its remote, high altitude site in the Andes of northern Chile. This wide-angle view shows some of the racks of the correlator in the ALMA Array Operations Site Technical Building. This photograph shows one of four quadrants of the correlator. The full system has four identical quadrants, with over 134 million processors, performing up to 17 quadrillion operations per second. #

Scientists work at the radio telescope control station of the ALMA project, in the Chajnantor plateau, Atacama desert, some 1,500 km north of Santiago, Chile, on October 1, 2011. #

One of most famous spiral galaxies is Messier 104, widely known as the "Sombrero" because of its particular shape. It is located towards the constellation Virgo, at a distance of about 30 million light-years. #

A composite color image of the Horsehead Nebula and its immediate surroundings, based on three exposures in the visual part of the spectrum with the FORS2 multi-mode instrument at the 8.2-m KUEYEN telescope at Paranal. It was produced from three images, obtained on February 1, 2000. #

This image, taken with the VLT Survey Telescope (VST) shows a wide variety of interacting galaxies in the young Hercules galaxy cluster. The sharpness of the picture and the sheer number of objects captured -- across a full square degree -- in less than three hours of observations attest to the great power of the VST and its OmegaCAM camera to explore the nearby Universe. #

The residence for astronomers of the European Southern Observatory (ESO) at the Cerro Paranal Observatory, photographed on September 15, 2008. The residence was built below ground to minimize the impact on the environment and to avoid the artificial light to spoil the night sky. This site was also used as one of the locations for the 2008 James Bond film "Quantum of Solace". #

The Atacama Large Millimeter/submillimeter Array, under construction. ALMA will be initially composed of 66 antennas, consisting a main array of fifty 12-meter antennas that can be spread over distances from 150 metres to 16 kilometers. In addition to the main array, ALMA will also have a compact array, composed of four 12-meter antennas plus twelve 7-meter 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. #

The KMOS spectrograph, shown when it was undergoing tests at the UK Astronomy Technology Center in Edinburgh, before it was shipped to Chile to become a powerful new instrument on the VLT. The 24 robotic arms are visible. #

In this image released April 25, 2011, taken atop Cerro Paranal, the 2,600-meter-high mountain in Chile's Atacama Desert, home to the VLT, the atmospheric conditions are so exceptional that fleeting events such as the "green flash" of the setting Sun are seen relatively frequently. ESO Electronics Engineer Gerhard Hudeepohl captured an even rarer sight: a green flash from the Moon, instead of the Sun. #

The 8.2m diameter main mirror of Antu, the first Unit Telescope of ESO's Very Large Telescope, is cleaned using carbon dioxide snow. While the telescope enclosure is maintained extremely clean, the mirrors are exposed to the elements during the observations. Consequently, dust from the desert slowly accumulates over the surface of the mirror, making it less reflective over time. The mirror's surface is so delicate that normal cleaners used for household mirrors are not appropriate. Observatories have developed other methods, such as this one using carbon dioxide snow. The tiny CO2 snowflakes in the white plume have a temperature of minus 80 degrees Celsius; when they land on the mirror, which is at room temperature, they cause minuscule 'explosions' that detach the dust grains from the surface. The dust then floats away, leaving the mirror clean. #

The dynamism of ESO's Very Large Telescope in operation is wonderfully encapsulated in this unusual photograph, taken just after sunset at the moment Unit Telescope 1 starts work. An extended exposure time of 26 seconds has allowed ESO Photo Ambassador Gerhard Huedepohl to record the movement of the dome, looking out through the opening from within, as the system swings into action. The rotating walls of the dome look like an ethereal swirl through which a slice of the Atacama Desert can be glimpsed, while the crisp dusk sky provides a splash of cool blue. #

Color composite image of Centaurus A, revealing the lobes and jets emanating from the active galaxy's central black hole. This is a composite of images obtained with three instruments, operating at very different wavelengths. The 870-micron submillimeter data, from LABOCA on APEX, are shown in orange. X-ray data from the Chandra X-ray Observatory are shown in blue. Visible light data from the Wide Field Imager #

Observations using the Atacama Large Millimeter/submillimeter Array (ALMA) have revealed an unexpected spiral structure in the material around the old star R Sculptoris. This feature has never been seen before and is probably caused by a hidden companion star orbiting the star. This slice through the new ALMA data reveals the shell around the star, which shows up as the outer circular ring, as well as a very clear spiral structure in the inner material. #

A color composite of visible and near-infrared images of the dark cloud Barnard 68. It was obtained with the 8.2-m VLT ANTU telescope and the multimode FORS1 instrument in March 1999. At these wavelengths, the small cloud is completely opaque because of the obscuring effect of dust particles in its interior. #

The barren Atacama Desert in northern Chile, with part of the ESO's VLT observatory visible. The four 8.2-meter Unit Telescopes stand out to the right on the summit of Mount Paranal. To the left looms the 4.1-meter Visible and Infrared Survey Telescope for Astronomy (VISTA), the largest survey telescope in operation. #

High in the Chilean Andes, at 5,000 metres above sea level, one of the giant Atacama Large Millimeter/submillimeter Array (ALMA) antenna transporters contemplates an unexpected sight -- a delicate dusting of snow whitens the landscape of the Chajnantor plateau. Snow is a very rare event at this extremely arid site and is a consequence of the Altiplanic winter, caused when the jet stream reverses and comes from the chill east. Chajnantor is one of the driest sites in the world, making it excellent for astronomical observations. The hill in the background is Toco, a 5600-meter mountain toward the north. This image was taken on 30 April 2010. The ALMA transporters, two giant custom-built vehicles, can move the antennas across the Chajnantor plateau, allowing different configurations of the array. #

This VISTA image shows the spectacular 30 Doradus star-forming region, also called the Tarantula Nebula. At its core is a large cluster of stars known as R 136, in which some of the most massive stars known are located. This infrared image, made with ESO's VISTA survey telescope. #

The NGC 1365 galaxy, also known as the Great Barred Spiral Galaxy, in an image that combines observations performed through three different filters with the 1.5-meter Danish telescope at the European Southern Observatory (ESO) in Chile, on September 22, 2010. The galaxy, at 60 million light-years from Earth, 200,000 light-years across and about twice the size of the Milky Way, is one of the largest known to astronomers. #

As soon as the Sun sets over the Chilean Atacama Desert, ESO's VLT begins catching light from the far reaches of the Universe. The VLT has four 8.2-meter Unit Telescopes such as the one shown in the photograph. Many of the photons that are collected have traveled 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 reflection nebula Messier 78, captured using the Wide Field Imager camera on the MPG/ESO 2.2-meter telescope at the La Silla Observatory, Chile. This color picture was created from many monochrome exposures taken through blue, yellow/green and red filters, supplemented by exposures through a filter that isolates light from glowing hydrogen gas. #

This evocative image shows a dark cloud where new stars are forming along with a cluster of brilliant stars that have already emerged from their dusty stellar nursery. This cloud is known as Lupus 3 and it lies about 600 light-years from Earth in the constellation of Scorpius (The Scorpion). It is likely that the Sun formed in a similar star formation region more than four billion years ago. This picture was taken with the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile and is the best image ever taken of this little-known object. #

This aerial view shows beautifully the Chilean Atacama Desert around the ESO Paranal Observatory, home to the VLT (at bottom right). Close to the VLT, one can see the dome of the VISTA survey telescope, and to the right, the Paranal Residence and basecamp. The high peak in the distance is the 6,739-meter high Andean volcano named Llullaillaco. Also in the image, to the middle left, one can see an isolated peak with a curvy road leading to its summit. This is Cerro Armazones, the selected home for the future European Extremely Large Telescope (E-ELT). #