Veckans bild

20 augusti 2012: A powerful laser beam from ESO’s Very Large Telescope (VLT) paints the night sky over the Chilean Atacama Desert in this stunning image taken by Julien Girard. The Earth’s rotation during the 30-minute exposure — and the movement of the laser as it compensated for this — is why the beam appears to fan out. This is also why the stars are stretched into curved trails, revealing subtle differences in their colours. The laser is used to create a point of light — an artificial star — by making sodium atoms 90 kilometres up in the Earth’s atmosphere glow. Measurements of this so-called guide star are used to correct for the blurring effect of the atmosphere in astronomical observations — a technique known as adaptive optics. While sufficiently bright natural stars are also used for adaptive optics, a laser guide star can be positioned wherever it is needed, meaning that ...

13 augusti 2012: Standing watch over the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA), Orion, the Hunter, shines high in the Chilean night sky. With its distinctive hourglass shape and the three bright stars of Orion’s Belt in the centre, the constellation is easily recognisable. Taken from the southern hemisphere, this image shows Orion’s sword above the Belt. The sword is home to one of the most stunning features of the sky — the Orion Nebula — which appears as the middle “star” in the sword, its fuzzy nebulosity visible to the naked eye under good conditions. The three ALMA antennas visible in the image represent only a small part of the complete ALMA array, which has a total of 66 antennas. ALMA combines the signals from its antennas, separated over distances of up to 16 kilometres, to form a single giant telescope, using a technique called interferometry. While construction is not ...

6 augusti 2012: ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special Then and Now comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal Observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany. This pair of pictures shows a view from the entrance of the Paranal Observatory site in northern Chile, looking towards the summit of Cerro Paranal, as seen in 1987 and in the present day. The Cerro Paranal region was first scouted out as a possible site for the future Very Large Telescope (VLT) in 1983 by a team including ESO’s Director General at that time, Lodewijk Woltjer (see The Messenger, No. 64, pp 5–8 for more information). In 1987 a dirt road to the summit ...

30 juli 2012: On Earth, cocoons are associated with new life. There are “cocoons” in space too, but, rather than protecting pupae as they transform into moths, they are the birthplaces of new stars. The red cloud seen in this image, taken with the EFOSC2 instrument on ESO’s New Technology Telescope, is a perfect example of one of these star-forming regions. This is a view of a cloud called RCW 88, which is located about ten thousand light-years away and is about nine light-years across. It is not made of silk, like a moth’s cocoon, but of glowing hydrogen gas that surrounds the recently formed stars. The new stars form from clouds of this hydrogen gas as they collapse under their own gravity. Some of the more developed stars, already shining brightly, can even be seen peering through the cloud. These hot young stars are very energetic and emit large amounts of ultraviolet ...

23 juli 2012: Looking down from a vantage point at the ESO Very Large Telescope on Cerro Paranal in the Chilean Atacama Desert, the observatory’s basecamp stretches out below. The Paranal Residencia, a haven for those working on the mountain, can be seen near the centre with the dome on its roof. To the left of the Residencia, on the other side of the road, is the basecamp’s gymnasium, and to the left of that is the Mirror Maintenance Building (MMB), where the giant VLT mirrors are periodically cleaned and recoated. Behind the MMB is the site’s power station, and further to the left is the mechanical workshop building. Winding up the mountainside in the foreground is the Star Track, a walking path from the Residencia to the summit. The Sun had set about a quarter of an hour before this photograph was taken, leaving the basecamp bathed in beautiful orange light. This ...

16 juli 2012: This photograph shows one of the 12-metre-diameter European antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) being moved at the project’s Operations Support Facility. Since this photograph was taken, this antenna, and others like it, have been put into operation as ALMA has begun scientific observations with a partial array (see eso1137). Most recently, the Call for Proposals for ALMA’s next phase of observations closed on Thursday 12 July. Over 1100 proposals were received from astronomers around the world. ALMA makes its observations on the Chajnantor plateau at an altitude of 5000 metres. Once construction is completed, ALMA will have an array of 66 high-precision 12-metre- and 7-metre-diameter antennas, spread over distances of up to 16 kilometres, working together as a single telescope at wavelengths of 0.32 to 3.6 millimetres. More than half of the 66 antennas are already on Chajnantor (see ann12035). Twenty-five ALMA antennas are being provided by ...

9 juli 2012: The Cat’s Paw Nebula is revisited in a combination of exposures from the MPG/ESO 2.2-metre telescope and expert amateur astronomers Robert Gendler and Ryan M. Hannahoe. The distinctive shape of the nebula is revealed in reddish puffy clouds of glowing gas against a dark sky dotted with stars. The image was made by combining existing observations from the 2.2-metre MPG/ESO telescope of the La Silla Observatory in Chile (see ESO Photo Release eso1003) with 60 hours of exposures on a 0.4-metre telescope taken by Gendler and Hannahoe. The resolution of the existing 2.2-metre MPG/ESO telescope observations was combined (by using their “luminance” or brightness) with the colour information from Gendler and Hannahoe’s observations to produce a beautiful combination of data from amateur and professional telescopes. For example, the additional colour information brings out the faint blue nebulosity in the central region, which is not seen in the original ESO image, ...

2 juli 2012: ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special Then and Now comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal Observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany. Since February 2002 (see eso0205), the Paranal Residencia has provided accommodation for people working shifts at ESO’s flagship observatory site. Paranal, in Chile’s Atacama Desert, is the home of ESO’s Very Large Telescope (VLT). This month, our Then and Now photographs — both taken by ESO Photo Ambassador Gerhard Hüdepohl — give us a unique view of how this oasis in the desert was built. The historical photograph shows the Residencia under construction at the end of 2000. The building was designed by German architecture ...

25 juni 2012: On a cold dark night on Mars, in the middle of an arid desert, a narrow road lit by artificial lights winds its way up to a lonely human outpost on the top of an old mountain. Or at least, that’s what a science fiction fan might make of this almost unearthly view. The photograph actually shows ESO’s Paranal Observatory, home to the Very Large Telescope (VLT), on Earth. Nevertheless, it’s easy to imagine it as a future view of Mars, perhaps at the end of the century. Which is why Julien Girard, who took this photograph, calls it “Mars 2099”. Located at 2600 metres altitude, ESO’s Paranal Observatory sits in one of the driest and most desolate areas on Earth, in Chile’s Atacama Desert. The landscape is so Martian, in fact, that the European Space Agency (ESA) and NASA test their Mars rovers in this region. For example, an ...

18 juni 2012: One of the major enemies of astronomers is the Earth’s atmosphere, which makes celestial objects appear blurry when observed by ground-based telescopes. To counteract this, astronomers use a technique called adaptive optics, in which computer-controlled deformable mirrors are adjusted hundreds of times per second to correct for the distortion of the atmosphere. This spectacular image shows Yepun [1], the fourth 8.2-metre Unit Telescope of ESO’s Very Large Telescope (VLT) facility, launching a powerful yellow laser beam into the sky. The beam creates a glowing spot — an artificial star — in the Earth’s atmosphere by exciting a layer of sodium atoms at an altitude of 90 km. This Laser Guide Star (LGS) is part of the VLT’s adaptive optics system. The light coming back from the artificial star is used as a reference to control the deformable mirrors and remove the effects of atmospheric distortions, producing astronomical images almost as ...

11 juni 2012: Many astronomical photographs capture stunning vistas of the skies, and this is no exception. However, there’s something unusual about this panorama. Behind ESO’s Very Large Telescope (VLT), two streams of stars seem to cascade down like waterfalls, or perhaps rise like smoke columns to the heavens. That’s because this panorama captures the entire dome of the sky, from the zenith down to the horizon, a full 360 degrees around. The two streams are in fact a single band: the plane of our galaxy, the Milky Way, as it arcs across the sky from horizon to horizon. As it passes overhead, it appears to spread out across the whole top edge of the panorama, due to the distortion needed to squeeze the fulldome of the sky into a flat, rectangular image. To understand the picture, imagine that the far left side is attached to the far right, creating a loop around ...

4 juni 2012: ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special Then and Now comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal Observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany. Our pair of photographs this month show how the computing power used by ESO has changed dramatically over time. Both photographs show Austrian astronomer Rudi Albrecht in front of ESO’s computer systems, but on dates separated by decades. In the historical image, taken in 1974 in the ESO offices in Santiago, Chile, we can see Albrecht, pencil in hand, poring over code in front of a teletype. He was working on software for the Spectrum Scanner attached to the ESO 1-metre telescope [1] located at ...

28 maj 2012: ESO Photo Ambassador Babak Tafreshi snapped this remarkable image of the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA), set against the splendour of the Milky Way. The richness of the sky in this picture attests to the unsurpassed conditions for astronomy on the 5000-metre-high Chajnantor plateau in Chile’s Atacama region. This view shows the constellations of Carina (The Keel) and Vela (The Sails). The dark, wispy dust clouds of the Milky Way streak from middle top left to middle bottom right. The bright orange star in the upper left is Suhail in Vela, while the similarly orange star in the upper middle is Avior, in Carina. Of the three bright blue stars that form an “L” near these stars, the left two belong to Vela, and the right one to Carina. And exactly in the centre of the image below these stars gleams the pink glow of the Carina ...

21 maj 2012: Babak Tafreshi, one of the ESO Photo Ambassadors, has captured a curious phenomenon on the Chajnantor plateau, the site of the Atacama Large Millimeter/submillimeter array (ALMA). These bizarre ice and snow formations are known as penitentes (Spanish for “penitents”). They are illuminated by the light of the Moon, which is visible on the right on the photograph. On the left, higher in the sky, the Large and Small Magellanic Clouds can be faintly seen, while the reddish glow of the Carina Nebula appears close to the horizon on the far left. The penitentes are natural marvels found in high-altitude regions, such as here in the Chilean Andes, typically more than about 4000 metres above sea level. They are thin spikes and blades of hardened snow or ice, which often form in clusters, with their blades pointing towards the Sun. They attain heights ranging from a few centimetres, resembling low grass, ...

14 maj 2012: This 360 degree panorama shows one of ESO’s Very Large Telescope (VLT) Unit Telescopes (UT4) whilst it was recently briefly held prisoner by ESO’s engineers. It was surrounded by a temporary cage of scaffolding as part of the preparations for the new Adaptive Optics Facility (AOF). This project will convert UT4 into a fully adaptive telescope. The AOF will correct for the blurring effects of the Earth’s atmosphere and will allow much sharper images to be achieved with the HAWK-I and MUSE instruments. Many new components are being added to UT4 as part of the AOF. Among these is the deformable secondary mirror (DSM): a thin-shell mirror, 1.1 metres in diameter, but just 2 millimetres thick. This mirror is thin enough to be easily deformed by more than a thousand actuators, up to a thousand times per second in order to counteract the atmosphere’s distortions. The DSM is the largest ...

7 maj 2012: ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into its history. Once a month during 2012, a special Then and Now Picture of the Week shows how things have changed over the decades at the La Silla and Paranal observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany. These two photographs were taken on the highest peak of La Silla, a mountain with an altitude of 2400 metres, at the edge of the Chilean Atacama Desert. La Silla was ESO’s first observatory site. The historical photograph, taken in 1975, shows some of the trucks and other equipment used for the construction of the dome of the ESO 3.6-metre telescope, which was underway behind the photographer. On the left are the water tanks for the site. In the modern-day photograph, three new telescopes have appeared, ...

30 april 2012: The otherworldly beauty of Chile’s Atacama Desert, home of ESO’s Very Large Telescope (VLT), stretches to the horizon in this panorama. On Cerro Paranal, the highest peak in the centre of this image, are the four giant Unit Telescopes of the VLT, each of which has a mirror with a diameter of 8.2 metres. On the peak to the left of Cerro Paranal is the VISTA survey telescope. This 4.1-metre telescope surveys broad swathes of the heavens, searching for interesting targets which the VLT, as well as other telescopes on the ground and in space, will study in greater detail. This region offers some of the best conditions for viewing the night sky found anywhere on our planet. On the right of this 360-degree panorama, the Sun is setting over the Pacific Ocean, throwing long shadows across the mountainscape. On the left, the Moon gleams in the sky. Soon, the ...

23 april 2012: Vid ALMA i de chilenska Anderna fångade ESO:s fotoambassadör Stéphane Guisard denna häpnadsväckande panoramabild. Här, 5000 meter över havet på Chajnantorplatån, är förhållanden perfekt torra för detta toppmoderna teleskop, som studerar universum i ljus med våglängd kring en millimeter. I mitten av bilden syns ALMA:s 54 jätteantenner. Ovan antennerna bildar Vintergatans mäktiga båge en storartad fond. När bilden togs låg dessutom månen nära Vintergatans mitt och skänkte antennerna en nästan kuslig nattstämning. På himlen framträder även Vintergatans två största granngalaxer, de Magellanska molnen, som två lysande fläckar till vänster i bilden. Nära det Lilla magellanska molnet syns även spåret efter en ljusstark meteor. Till höger syns några av ALMA:s mindre 7 meters-antenner – tolv sådana antenner bildar Atacama Compact array. Ännu längre till höger lyser lamporna i den tekniska byggnaden som ligger på platån. Och allra längst till höger, bakom byggnaden, ligger den mörka bergstoppen Cerro Chajnantor. ALMA är en ...

16 april 2012: The Atacama Pathfinder Experiment (APEX) telescope looks skyward during a bright, moonlit night on Chajnantor, one of the highest and driest observatory sites in the world. Astronomical treasures fill the sky above the telescope, a testament to the excellent conditions offered by this site in Chile’s Atacama region. On the left shine the stars that make up the tail of the constellation of Scorpius (The Scorpion). The scorpion’s “stinger” is represented by the two bright stars that are particularly close to each other. Reaching across the sky and looking like a band of faint, glowing clouds is the plane of the Milky Way. Between Scorpius and the next constellation to the right, Sagittarius (The Archer), which looms over APEX’s dish, a sparkling cluster of stars can be clearly seen. This is the open cluster Messier 7, also known as Ptolemy’s Cluster. Below Messier 7 and slightly to the right is ...

9 april 2012: Although Cerro Chico reaches the remarkable altitude of 5300 metres above sea level, it is only a small mountain in the majestic landscape of the Andean plateaux. Indeed, its own name means simply “small mountain” in Spanish. However, due to its position on the plateau of Chajnantor, the top of Cerro Chico offers an excellent and relatively easy-to-reach vantage point from which to enjoy this stunning view. This 360 degree panorama picture is centred on the northeast, where the highest volcanoes — most of them above 5500 metres — are seen. In the centre is Cerro Chajnantor itself. To the right, on the plateau, is the Atacama Pathfinder Experiment (APEX) telescope with Cerro Chascon behind it. Further to the right, to the southeast, the Chajnantor plateau is almost fully visible. In addition to the APEX telescope, three Atacama Large Millimeter/submillimeter Array (ALMA) antennas can be seen, on the right. Many ...