Picture of the Week

15 September 2014

Morning Light Over La Silla

Here we see ESO's La Silla Observatory with a backdrop of the Milky Way. Established in the 1960s, La Silla was ESO's first observatory to be built in Chile.

Visible on the hill in the centre of this image is the rectangular New Technology Telescope (NTT) on the left, and the domed ESO 3.6-metre telescope to the right. The 3.58-metre NTT was inaugurated in 1989, and was the first in the world to have a computer-controlled main mirror. The main mirror is flexible, and its shape is actively adjusted during observations to preserve the optimal image quality. This technology, known as active optics, is now applied to all major modern telescopes — including the Very Large Telescope at Cerro Paranal, and the future European Extremely Large Telescope.

La Silla is home to several other telescopes, including the Swedish–ESO Submillimetre Telescope (SEST), and the robotic TAROT, which is used to monitor rapidly occurring events such as gamma-ray bursts.

This picture was taken by ESO Photo Ambassador José Joaquín Pérez. When José is not taking stunning photos of the night sky, he works as an agricultural engineer where he devotes his time to the protection of crops in central Chile.


8 September 2014

VLT Tracks Rosetta's Comet

The bright, hazy smudge at the centre of this image is a comet known as 67P/Churyumov-Gerasimenko, or 67P/C-G for short. This is not just any comet; it is the target for ESA’s Rosetta spacecraft, which is currently deep within the comet’s coma and less than 100 kilometres from its nucleus [1]. With Rosetta so close to the comet, the only way to view the whole of 67P/C-G now is to observe it from the ground.

This image was taken on 11 August 2014 using one of the 8-metre telescopes of ESO’s Very Large Telescope (VLT) in Chile. It was composed by superimposing 40 individual exposures, each lasting 50 seconds, and removing background stars, to obtain the optimal view of the comet. Rosetta is contained within the central pixel of this image, and is too small to resolve.

The VLT is made up of four individual Unit Telescopes that can work together or individually to study the night sky. These observations used the FORS2 (FOcal Reducer and low dispersion Spectrograph 2) instrument on Unit Telescope 1, otherwise known as Antu, which is the indigenous Chilean Mapuche term for the Sun.

FORS2 can be used in various ways, but for the Rosetta campaign astronomers use it to image the comet and determine its brightness, size and shape; and also to analyse the coma’s composition.

Although 67P/C-G is faint in this image, it is clearly active, with a dusty coma extending some 19 000 kilometres out from the nucleus. This coma is asymmetric as the dust is being swept away from the Sun — which is located beyond the lower right corner of the image — and is beginning to form a characteristic cometary tail.

This VLT image is part of an ongoing collaboration between ESA and ESO to observe 67P/C-G from the ground while Rosetta is performing measurements at the comet. On average, the VLT obtains images of the comet every second night. These short exposures are used to monitor the comet's activity by studying how its brightness changes. The results are reported back to the Rosetta project and provide part of the information for planning how to orbit around it.

Notes

[1] Rosetta reached a distance of 100 kilometres from 67P/C-G’s nucleus on 6 August 2014, and has been moving closer to the comet since then.

More information


1 September 2014

Psychedelic Skies

This groovy and psychedelic photograph shows a night of observing the Northern Celestial Pole from the Allgäu Public Observatory in Ottobeuren, Germany. Pictured here is the facility's 0.6-metre Cassegrain reflector telescope, which was installed in 1996.

The brilliant yellow laser beam, which appears to fan out across the sky in this long-exposure image, is ESO's Wendelstein laser guide star unit which was tested at the site in Allgäu. It is a precursor, experimental version of the fibre laser that has been installed on the Very Large Telescope in Paranal, Chile.

A Laser guide star is used to create a bright spot in the sky, which can be used as an artificial reference star, allowing astronomers to measure how the real stars blur or twinkle, as normally seen from the ground. The measurements are then used to correct this blurring and enable sharper images to be taken, in a process is known as adaptive optics.

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25 August 2014

Star Rain in the Desert

In the Atacama Desert in Chile, it rarely rains. Only once every few years does significant rain or snow precipitate on ESO’s La Silla Observatory, generally coinciding with an anomalously warm weather event such as an El Niño event. This desert is one of the driest places on Earth, making it a fantastic site from which to observe the night sky.

Although there may be very little real rain, some photography tricks can instead make the stars appear to rain onto the surrounding mountains, as seen in this image taken on 21 May 2013 by Diana Juncher, a PhD student in astronomy at the Niels Bohr Institute, Denmark.

Diana was at La Silla for two weeks in May 2013, observing exoplanets towards the centre of our galaxy as part of her research. During her stay she managed to take this image of star trails, taken only around 20 metres away from the Danish 1.54-metre telescope at ESO’s La Silla Observatory. Star trail photographs like these are shot using a long exposure time in order to capture the apparent motion of the stars as the Earth rotates.

A wisp of snow covers the distant mountain tops, and soft clouds can be seen below La Silla, near the horizon to the left. The slightly darker and redder area to the right is an open copper mine. Copper is Chile's biggest economic asset — the country is by far the world leader in copper production.

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18 August 2014

Sculpting La Silla’s Skies

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.


11 August 2014

Carving a Route to Armazones

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.


4 August 2014

In Search of Space

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.

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28 July 2014

Alien Atacama

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.


21 July 2014

Giants at Work

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.


14 July 2014

A Deep Look into a Dark Sky

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.

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7 July 2014

A Bird’s-eye View of ESO

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).

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30 June 2014

Impression, sunset

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.


23 June 2014

The VLT’s Artificial Star

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.


16 June 2014

The Road to the Future

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.


9 June 2014

Sunrise over the VLT

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.

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2 June 2014

Cloaked in Stars

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.

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26 May 2014

A Stream of Stars over Paranal

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.


19 May 2014

Big and Bigger

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.


12 May 2014

Star Trails over Atacama Desert Cacti

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.


5 May 2014

Planets Align Over La Silla

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.

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