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.
ESO's observatories are privileged spots where astrophotographers can catch amazing views of the cosmos. But that's not all — sometimes, they are ideal locations from which to capture otherworldly images of our own planet, too. In this shot, ESO photo ambassador Gabriel Brammer has used a fish-eye lens to create this spectacular round effect. The clear sky over Paranal looks like a glass ball full of stars, with the Very Large Telescope (VLT) platform framing the picture.
In the bottom left the four VLT Unit Telescopes, each some 25 metres tall, are observing the night sky, one of them pointing its laser up into the night. Scattered around the top left of the frame, the round domes of the VLT Auxiliary Telescopes are easily spotted under the bright Milky Way. The two blurry smudges just above the laser are the Large and Small Magellanic Clouds, two of the closest galaxies to our own.
This image is created from a number of different wide-angle pictures, stitched together to show the complete view.
Another clear night at ESO’s Paranal Observatory in Chile — perfect for sitting back and taking in the sight of our galaxy, the Milky Way. Many of us living in living in crowded, light-polluted cities no longer get to see our cosmic home in such detail.
We now know this stunning view to be our home galaxy, but the Ancient Greeks thought that it was the work of the Gods. Their legends told that this cloudy streak across the sky was really the breast milk of Hera, wife of Zeus. The Ancient Greeks are also to thank for the name “Milky Way”. The Hellenistic phrase Γαλαξίας κύκλος, pronounced galaxias kyklos, means “milky circle”, and provides the root for our modern name.
This 360 degree panorama image was taken by ESO Photo Ambassador Gabriel Brammer. An astronomer visiting Paranal can be seen standing towards the right hand side of this image admiring the view.
From our vantage point on Earth, comet 67P/CG has only just reappeared from behind the Sun. On 28 February 2014 ESO's Very Large Telescope (VLT) directed its gaze towards the comet as soon as it became visible from ESO's Paranal Observatory in Chile. ESO is collaborating with ESA to monitor the comet from the ground as it is approached by Rosetta over the coming months. These observations will prepare for the spacecraft's major rendezvous with the comet, planned for August of this year (see potw1403a).
This new image, and many more to come, will be used by ESA to refine Rosetta's navigation, and to monitor how much dust the comet is releasing. The image on the left was created by stacking the individual exposures to show the background stars — they were then shifted to compensate for the motion of the comet, which appears as a small dot right on top of one of the star trails (at the centre of the circle). The image on the right shows the comet with the stars subtracted out.
This new image shows a brightening of the comet, indicating that the ice at its heart has started to evaporate as it warms up in its approach to the Sun. Just like the Rosetta spacecraft, the comet itself is emerging from hibernation.
High on the Chajnantor Plateau in the Chilean Andes lies the Atacama Large Millimeter/submillimeter Array (ALMA), an observatory surrounded by large expanses of dry landscape. Perhaps surprisingly, the region is home to a number of different wildlife species, many of which occasionally pop up near to the observatory. Further south, ESO’s La Silla Observatory recently had visits from a South American grey fox (potw1406a), and wild horses (potw1344a).
The most recent cute visitor to ALMA is this vicuña fawn, found on 16 February 2014 by ALMA workers. The fawn was only a few weeks old, weakened after it was chased by foxes until it lost sight of its herd.
After a couple of unsuccessful attempts the following day to return the fawn to its herd, the workers transferred it to the Wildlife Rescue and Rehabilitation Center at the Universidad de Antofagasta, where it is being treated so that it can eventually be released on the Andean plateau approximately one year from now.
Bereft of colour in this striking infrared image, the sweeping curves of ESO's Headquarters clash with the frosty natural beauty of the surrounding trees. The extreme curvature visible in this image is due to the photographer's use of a fisheye lens, which distorts the view and causes the building to encircle the pale foliage and frame the sky above. The foliage appears to be bright as it reflects the infrared light, and the pale white hue comes from the photographer applying a white colour balance to the tree leaves.
The precise curves of concrete, glass, and steel give clues as to the Headquarters building's peculiar structure. In 1981 an article in ESO's The Messenger described the ESO building as "a labyrinth of the kind used to test the intelligence of rats". But, fortunately for ESO, the writer soon noted that "human beings are on average cleverer than rats, and the problem is quickly solved".
This image was taken by ESO computer specialist Dirk Essl.
Launched on the morning of Thursday, 19 December 2013, the satellite is on a quest to build a 3D map of our galaxy over the next five years. Mapping the sky has been one of humanity's quests since the dawn of time, and Gaia will take our understanding of our stellar neighbourhood to a whole new level. It will measure very precisely the positions and motions of about one billion stars in our galaxy, to explore the Milky Way's composition, formation and evolution.
These new observations are the result of a close collaboration between ESA and ESO to monitor the spacecraft from the ground. Gaia is the most accurate astrometric device ever built, but in order for its observations to be useful it needs to know exactly where it is in the Universe. The only way to know the velocity and position of the spacecraft with very high precision is to observe it on a daily basis from the ground — using telescopes including ESO's VST in a campaign known as Ground-Based Optical Tracking, or GBOT.
The VST is a state-of-the-art 2.6-metre telescope equipped with OmegaCAM, a monster 268-megapixel CCD camera with a field of view four times the area of the full Moon. The VST captured these images using OmegaCAM on 23 January 2014, taken about 6.5 minutes apart. Gaia is clearly visible as a small spot moving against a background of stars. Its location is circled in red. In these images, the spacecraft is about a million times fainter than is detectable by the naked eye.
Gaia was previously observed in December 2013 by the VST, very soon after its launch — it is one of the closest objects ever observed by the VST. It appeared in precisely the location expected, highlighting a successful collaboration between ground- and space-based astronomy!
Perched precariously on the edge of the habitable world, life manages to cling on. On the outskirts of the hot, dry Atacama Desert, this hardy South American grey fox has just awoken, stretching leisurely. These foxes are generally active during the night, making the most of the drop in temperature that comes with a respite from the hot Chilean Sun.
In the background there are other signs of life. This white dome houses the Swiss 1.2-metre Leonhard Euler Telescope, which is protected from the harsh conditions by its outer shell. As the skies grow darker at ESO’s La Silla Observatory another famously nocturnal species, the astronomer, wakes up, stretches, and gets ready to scan the skies with buzzing and whirring technology.
This image was taken by ESO Photo Ambassador Malte Tewes and submitted 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.
This beautiful panorama of ESO's Paranal Observatory was taken on 5 July 2012, and marks one of the driest days ever recorded at the Very Large Telescope complex. Paranal sits like an island in the middle of the frame, with massive cloud banks floating below, over the distant Pacific Ocean.
The extremely low humidity at Paranal during this period was recorded by a water vapour radiometer known as LHATPRO, which monitors the atmosphere to support the observations carried out at the observatory . Meteorologists from two Chilean universities identified the cause for these unusually dry conditions: high-altitude Antarctic air moving far to the north, and descending over Paranal.
This cold front lingered around Paranal for over 12 hours, causing a record-low level of humidity in the air above the observatory . Florian Kerber (ESO) and colleagues analysed this unusual weather, publishing the results in a paper in the Monthly Notices of the Royal Astronomical Society on 29 January 2014, available here.
So, a dry desert… what is so special about that? Well, dryness of this magnitude is normally experienced at much higher altitudes, for example at the ALMA Observatory on the Chajnantor Plateau, which is located at 5000 metres above sea level — at 2635 metres, the altitude of Paranal is around half of this. Given that infrared observations can be best taken when there is little water vapour in the air, this could mean that routine monitoring using the LHATPRO radiometer will give astronomers the opportunity to exploit future dry spells at Paranal, to obtain great infrared observations of the Universe around us.
The photo was taken by ESO photo ambassador Gabriel Brammer, who coincidentally experienced the sunset that immediately preceded this dry spell, and found it to be extraordinarily clear and beautiful. Gabriel works as an astronomer at the ESO La Silla-Paranal Observatory. When not supporting the operations of the observatory, he studies the formation and evolution of distant galaxies using the most sophisticated telescopes and instrumentation in the world, including the ESO Very Large Telescope and the Hubble Space Telescope.
 The Low Humidity and Temperature Profiling radiometer (LHATPRO), manufactured by Radiometer Physics GmbH in Germany, uses strong spectral lines from certain elements to measure the water content of the atmosphere.
 The humidity is measured in the form of precipitable water vapour — a measure of atmospheric water content. It is the amount of water in a column of the atmosphere if it were all to fall as rain. In this case only 0.1 mm of precipitable water vapour was measured — much less than the usual (but already low) figure of 2 mm at Paranal.
Astronomers do not always swim at the swimming pool at the Paranal Observatory Residencia, but when they do, they like to show how physical principles work. In this picture the French ESO astronomer Jean-Baptiste Le Bouquin is demonstrating how waves — not light waves, but water waves — can combine, or interfere, to create larger waves.
The combination of light waves is the main principle behind the VLT Interferometer: the light waves captured by each one of the four 8-metre telescopes are combined using a network of channels and mirrors. This way the spatial resolution of the telescope is vastly increased and, with enough exposure time, the cameras and instruments can reveal the same level of detail as a telescope with a 130-metre diameter mirror could, far bigger than any telescope in existence.
This image was taken by award-winning editorial and commercial photographer Max Alexander. See also Tribute to ESO’s Unsung Heroes, a video released by ESO for its 50th anniversary in 2012. The video is composed of a set of images, most of which were taken by Alexander, who was visiting the ESO sites for a project dedicated to ESO’s anniversary.
ESA's Rosetta spacecraft will wake up today, 20 January, after 31 months in deep space hibernation, to finally close in on comet 67P/Churyumov-Gerasimenko (67P/CG).
This image shows the most recent observations of the 4-kilometre diameter comet, taken on 5 October 2013 by ESO's Very Large Telescope (VLT) when the comet was around 500 million kilometres away — before it passed behind the Sun and out of view from Earth's perspective.
For this image, a long series of observations was processed to reveal both the comet without the background stars (on the left panel), and the star field with the track of the comet marked (on the right). Viewed against a crowded star field towards the centre of the Milky Way, the comet was still so far from the Sun that the icy nucleus was not releasing any gas or dust, and appears as a simple spot. As it approaches the Sun, its surface will heat up and its ices will sublimate, dragging dust out to form a tail.
The observation marks the start of a close collaboration between ESA and ESO to monitor the comet from the ground during Rosetta's encounter with 67P/CG later this year. Rosetta was launched in 2004 and aims to explore the surface of the comet, deploying a lander down onto 67P/CG to see what its surface is like .
The comet is on a 6.5-year orbit around the Sun and is currently out towards the orbit of Jupiter. It will be closest to the Sun — roughly between the orbits of Earth and Mars — in August 2015. This image suggests that the comet is not yet active, so scientists will be keen to check in on the comet again in February, when it is next observable by the VLT, and much closer to the Sun.
In the meantime, the observations carried out in October have been used to confirm the comet's orbit ahead of the major rendezvous manoeuvre planned for Rosetta in May, to line it up for orbiting 67P/CG in August. Further calculations will be made once Rosetta sights the comet in its own imaging system.
 Since its launch, Rosetta has travelled around the Sun five times, picking up speed and aligning itself with its final destination. For the coldest leg of the mission, as Rosetta ventured out beyond the orbit of Jupiter, the spacecraft was put into deep-space hibernation. 67P/CG is on a reasonably stable and well-known orbit, meaning that calculations for Rosetta's trajectory could be made far in advance of the spacecraft's launch, and it is far enough away from the Sun to make it a safe target.
- VLT snap of comet 67P/Churyumov-Gerasimenko in October 2013
- The path of comet 67P/Churyumov-Gerasimenko in October 2013
- ESA Space Science Image of the Week
- ESA information on Rosetta
- ESA Call for Media: Rosetta Wake Up Event
- ESO's Very Large Telescope
Thanks to ESO’s Photo Ambassadors we can enjoy sensational images taken at the ESO sites on the remote mountaintops of Chile. Babak Tafreshi has captured this fine panoramic view of the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) at twilight. Resembling a frame from a science fiction movie, the technological spectacle of ALMA against the raw natural power of the landscape on the Chajnantor Plateau, 5000 metres above sea level, results in fascinating images like this one.
There are a few details you shouldn't miss in this panoramic photo of ALMA (seen more clearly in the zoomable version), all lying between the two groups of antennas: the "Earth's shadow" and "Belt of Venus" phenomena, visible as the dark blue and light pink bands stretching across the sky, and the planet Jupiter, seen right above the mountain in the background.
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.
Gaze up at the night sky from ESO's Paranal Observatory in Chile, and you will be greeted with a stunning view like this one. Flecks of blue, orange, red; each a different star, galaxy, nebula, or more, together forming a sparkling sky overhead. Astronomers peer at this beautiful backdrop, trying to unravel the mysteries of the Universe.
To do this, they use telescopes like the ones shown here, the VLT Auxiliary Telescopes. This image shows three of the four moveable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: they reveal details that would be visible with a telescope as large as the distance between them.
When night falls, ESO's observatories spring to life. Astronomers and technicians take their positions, and telescopes are pointed skywards. This image shows the pristine skies over ESO's Paranal Observatory in the Chilean Atacama Desert, far away from city lights.
Here, ESO photo ambassador Gabriel Brammer has captured the serene beauty of the Milky Way from the platform of the Very Large Telescope. The four massive blocks in the bottom of the image are the four VLT Unit Telescopes, each of them housing incredibly precise 8.2-metre mirrors. Scattered around are the VLT's Auxiliary Telescopes, easily identifiable due to their round, white domes. The bright spot to the left is the Moon, shining as brightly as if it were the Sun, and to the right, the shadow of the photographer can be seen, waving to the viewer with outstretched arms.
The entire night sky is visible due to Brammer's use of a fish-eye lens, creating this circular effect with the ground bordering the frame.