Picture of the Week

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potw1139 — Picture of the Week
All Four VLT Unit Telescopes Working as One
26 September 2011: When light from all four 8.2-metre Unit Telescopes of ESO’s Very Large Telescope (VLT) in Cerro Paranal on 17 March 2011 was successfully combined for the first time (ann11021), ESO Photo Ambassador Gerhard Hüdepohl was there to capture the moment. Having all four of the Unit Telescopes (UTs) working as one telescope observing the same object was a major step in the development of the VLT. While mostly used for individual observations, the UTs were always designed to be able to operate together as part of the VLT Interferometer (VLTI). All the UTs are pointed in the same direction, at the same object, although this isn’t obvious because of the wide-angle lens used to take the photo. The light collected by each of the telescopes was then combined using an instrument called PIONIER [1]. When combined, the UTs can potentially provide an image sharpness that equals that of a telescope ...
potw1138 — Picture of the Week
The “Little World” of Paranal
19 September 2011: This interpretation of a previous Picture of the Week was created by astronomer Alex Parker. It captures some of the essence of Paranal Observatory — a little world where astronomers leave the Earth behind and travel to the stars... metaphorically at least. The observatory lies deep in the barren Atacama Desert, which can really seem like an alien environment. It is far from civilisation and modern life, a place where visiting astronomers spend their nights gazing out at the wonders of the Universe using ESO’s flagship facility, the Very Large Telescope (VLT). The VLT is the reason why Cerro Paranal was transformed from just another mountain in the Chilean Andes into a base for world-class scientific research. When night falls over Paranal, and the night sky is aglow with stars, nebulae and nearby galaxies, the unearthly view emphasises our place in the Universe — as Alex Parker so creatively demonstrates ...
potw1137 — Picture of the Week
Red Moon Rising
12 September 2011: Deep in the heart of the Atacama Desert, home of the Paranal Observatory, the Sun is setting at the start of another clear night. This charming photograph, taken by ESO Photo Ambassador Gianluca Lombardi shows one of four Auxiliary Telescopes (ATs) that belong to ESO’s Very Large Telescope (VLT) sitting boldly against a vivid sky of pink and blue. The full Moon, seen hovering over the horizon, has a distinctly reddish hue, a phenomenon caused by the scattering of light by Earth’s atmosphere. When the Moon is close to the horizon, the light we see from it must travel through a greater thickness of the atmosphere, so the effects of scattering are increased. As red light is more resilient to scattering than green or blue, our view of the Moon is reddened. As it happens, the reddening effect is somewhat less pronounced at sites like Paranal, as the clear air ...
potw1136 — Picture of the Week
Laser Meets Lightning
5 September 2011: As ESO tested the new Wendelstein laser guide star unit by shooting a powerful laser beam into the atmosphere, one of the region’s intense summer thunderstorms was approaching — a very visual demonstration of why ESO’s telescopes are in Chile, and not in Germany. Heavy grey clouds threw down bolts of lightning as Martin Kornmesser, visual artist for the ESO outreach department, took time-lapse photographs of the test for ESOcast 34. With purely coincidental timing this photograph was snapped just as lightning flashed, resulting in a breathtaking image that looks like a scene from a science fiction movie. Although the storm was still far from the observatory, the lightning appears to clash with the laser beam in the sky. Laser guide stars are artificial stars created 90 kilometres up in the Earth’s atmosphere using a laser beam. Measurements of this artificial star can be used to correct for the blurring ...
potw1135 — Picture of the Week
First 7-metre ALMA Antenna Arrives at Chajnantor
29 August 2011: The first of twelve 7-metre diameter ALMA antennas has just been transported on 24 August 2011 to the 5000-metre-high Chajnantor plateau, where the Atacama Large Millimeter/submillimeter Array (ALMA) is under construction. ALMA is a giant radio telescope composed of an array of fifty 12-metre antennas, as well as a smaller array known as the Atacama Compact Array (ACA). This will have a total of four 12-metre antennas and the twelve 7-metre dishes. The four 12-metre ACA antennas have already been moved up to the high plateau, but this is the first of the smaller 7-metre dishes — which put the “compact” into Atacama Compact Array — to reach Chajnantor. It is seen in the centre of this photograph, surrounded by some of the other ALMA antennas. Penitentes ice formations are seen in the foreground.The larger 12-metre antennas of the main array cannot be placed closer than 15 metres apart as ...
potw1134 — Picture of the Week
Flying over the ALMA Site: The Array Operations Site
22 August 2011: ALMA, the Atacama Large Millimeter/submillimeter Array, will be initially composed of 66 antennas, designed to observe the Universe in millimetre and submillimetre radiation. The main array will consist of fifty 12-metre antennas that can be spread over distances from 150 metres to 16 kilometres. In addition to the main array, ALMA will also have a compact array, composed of four 12-metre antennas plus twelve 7-metre 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. From the high altitudes of the Andes, ALMA will provide a revolutionary contribution to the search for our cosmic origins. 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 ...
potw1133 — Picture of the Week
As Time Goes By
15 August 2011: Just as the Sun rises in the east and sets in the west, so do the stars appear to slowly march across the sky. Their leisurely pace is imperceptible to a casual observer, but you can test the effect for yourself: on the next clear night note the position of a bright star, and then check again a few hours later. The change is not caused by the motion of the stars themselves, but rather the rotation of the Earth. Long-exposure photography is the ideal way to capture this motion. A camera is set up on a tripod, and the shutter opened to the sky. Normal snapshots gather light for a fraction of a second, but these special images need starlight to pour onto them for much longer, like a bucket collecting rainwater. To obtain this image, ESO Photo Ambassador Gianluca Lombardi collected light for a total of 25 minutes. ...
potw1132 — Picture of the Week
Dark Sky and White Desert — Snow pays a rare visit to ESO’s Paranal Observatory
8 August 2011: The night sky above Cerro Paranal, the home of ESO’s Very Large Telescope (VLT), is dark and dotted with the bright stars of the Milky Way, and more distant galaxies. But it is very rare to see the ground contrasting with the sky as markedly as in this photograph, which shows a gentle layer of white snow dotted with darker spots of the desert terrain beneath. The picture was taken last week, shortly before sunrise, by ESO Photo Ambassador Yuri Beletsky, who works as an astronomer at the La Silla Paranal Observatory. He captured not only the beautiful snowy landscape of the Atacama and the mountaintop domes of the VLT, but also an incredible night sky. To the left of the VLT is a satellite trail, and to the right is the trail of a meteor.Cerro Paranal is a 2600-metre-high mountain located in the Chilean Atacama Desert. It is a ...
potw1131 — Picture of the Week
Smoke Signals in Space
1 August 2011: The hazy and aptly named Fine Ring Nebula, shown here, is an unusual planetary nebula. Planetary nebulae form when some dying stars, having expanded into a red giant phase, expel a shell of gas as they evolve into white dwarfs. Most planetary nebulae are either spherical or elliptical in shape, or bipolar (featuring two symmetric lobes of material). But the Fine Ring Nebula — captured here by the ESO Faint Object Spectrograph and Camera mounted on the New Technology Telescope at the La Silla Observatory in Chile — looks like an almost perfect circular ring. Astronomers believe that some of these more unusually shaped planetary nebulae are formed when the progenitor star is actually a binary system. The interaction between the primary star and its orbiting companion shapes the ejected material. The stellar object at the centre of the Fine Ring Nebula is indeed thought to be a binary system, ...
potw1130 — Picture of the Week
Very Large Telescope Ready for Action
25 July 2011: This unusual 360-degree panoramic projection reveals the observing site from a fresh perspective. In the centre of the image, staff at Paranal have gathered to watch the sunset. On the right, the enclosures of the VLT’s Unit Telescopes can be seen: vast machines, each with a primary mirror 8.2 metres across and weighing 23 tonnes. Also visible are several of the smaller 1.8-metre Auxiliary Telescopes, which complement the Unit Telescopes. On the left of the picture is the control building, from where the telescopes are operated remotely during observations. No one remains inside the telescope domes after they are opened. Since first light in 1998 the Very Large Telescope has been used by ESO astronomers to study the Universe, including some of the most exotic phenomena known, such as exoplanets, supermassive black holes, and gamma-ray bursts. An amazing interactive virtual tour of Paranal is available here.
potw1129 — Picture of the Week
Hidden Treasure on Our Doorstep
18 July 2011: The MPG/ESO 2.2-metre telescope at La Silla in Chile is a powerful instrument that can capture distant celestial objects, but it has been used here to image a heavenly body that is much closer to home: the Moon. The data used for this image were selected by Andy Strappazzon from Belgium, who participated in ESO’s Hidden Treasures 2010 astrophotography competition. Andy’s composition of the Moon was the fourth highest ranked entry in the competition. This image of the crescent Moon shows sunlight skimming across the heavily pocked surface, filling its craters with shadows. This is a fairly flat region of the Moon, but elsewhere, high mountains can be found, with some peaks reaching about 5000 metres. When backlit by the Sun, these mountains cast long shadows on the lunar surface. In the 1600s, Galileo Galilei used these long shadows to determine the height of the peaks. At the Moon’s poles ...
potw1128 — Picture of the Week
A Galactic Embrace
11 July 2011: Two galaxies, about 50 million light-years away, are locked in a galactic embrace — literally. The Seyfert galaxy NGC 1097, in the constellation of Fornax (The Furnace), is seen in this image taken with the VIMOS instrument on ESO’s Very Large Telescope (VLT). A comparatively tiny elliptical companion galaxy, NGC 1097A, is also visible in the top left. There is evidence that NGC 1097 and NGC 1097A have been interacting in the recent past. Although NGC 1097 seems to be wrapping its companion in its spiral arms, this is no gentle motherly giant. The larger galaxy also has four faint jets — too extended and faint to be seen in this image — that emerge from its centre, forming an X-shaped pattern, and which are the longest visible-wavelength jets of any known galaxy. The jets are thought to be the remnants of a dwarf galaxy that was disrupted and cannibalised ...
potw1127 — Picture of the Week
A VLT Auxiliary Telescope and Cerro Armazones
4 July 2011: ESO Photo Ambassador Gianluca Lombardi was in the perfect position to capture a crisp dusk view of Auxiliary Telescope (AT) 2, on Cerro Paranal. Once the Sun sets, the cloudless skies above the Chilean desert will be filled with stars, and AT2 will begin its work. In the background on the left is Cerro Armazones, with a road zigzagging to its peak, home of the future European Extremely Large Telescope. Site-testing equipment can be seen on the peak. The lower peak to the right of Cerro Armazones is the site of smaller telescopes operated by the Instituto de Astronomía of the Universidad Católica del Norte. There are four ATs on Cerro Paranal, which form part of the Very Large Telescope (VLT). They are used for a special technique called interferometry, which allows multiple ATs, or the even larger Unit Telescopes, to combine their power and see details up to 25 ...
potw1126 — Picture of the Week
Hiding in Plain Sight — the elusive Carina Dwarf Galaxy
27 June 2011: It’s one of the closest galaxies to Earth, but the Carina Dwarf Galaxy is so dim and diffuse that astronomers only discovered it in the 1970s. A companion galaxy of the Milky Way, this ball of stars shares features with both globular star clusters and much larger galaxies. Astronomers believe that dwarf spheroidal galaxies like the Carina Dwarf are very common in the Universe, but they are extremely difficult to observe. Their faintness and low star density mean that it is easy to simply see right through them. In this image, the Carina Dwarf appears as many faint stars scattered across most of the central part of the picture. It is hard to tell apart stars from the dwarf galaxy, foreground stars within the Milky Way and even faraway galaxies that poke through the gaps: the Carina Dwarf is a master of cosmic camouflage. The Carina Dwarf’s stars show an ...
potw1125 — Picture of the Week
A Blood Moon over ESO’s Headquarters
20 June 2011: After nightfall on 15 June 2011 in Garching, near Munich, Germany, a blood-red Moon rose above the horizon. This striking phenomenon was caused by a total lunar eclipse in progress at moonrise, and it was captured in the skies over the European Southern Observatory’s Headquarters. A lunar eclipse takes place only when the Moon, Earth and Sun are exactly aligned. When the Moon passes through the shadow cast by the Earth, our planet blocks the path of direct sunlight to the lunar surface and a total eclipse occurs. This event can only happen on the night of a full Moon. Unlike the better known solar eclipses, the Moon doesn’t completely disappear from sight during a total lunar eclipse. Instead it appears painted blood red, giving it the ominous nickname of “blood Moon”. The reddish colour is caused by scattered sunlight that has passed through the Earth’s atmosphere — the same ...
potw1124 — Picture of the Week
By the Light of the Moon
13 June 2011: ESO Photo Ambassador Gianluca Lombardi used a remote shutter release and a 30-second exposure to take this night-time shot of himself sitting on a railing on the observing platform of the ESO Very Large Telescope (VLT). The VLT is on Cerro Paranal, at an altitude of 2600 metres in Chile’s Atacama Desert, one of the driest regions on Earth. The viewing conditions at Paranal are so superb that on a clear moonless night it is possible to see shadows cast by the light of the Milky Way alone.   In this photograph, however, the Moon is up, appearing as a bright light due to the long exposure. It is about to dip behind the VLT’s Unit Telescope 4 (UT4), named Yepun, and the shadows thrown by the moonlight are lengthening across the 200-metre width of the observing platform. The other three UTs stand in the background. From left to right they ...
potw1123 — Picture of the Week
A Slice of the Sky
6 June 2011: This spectacular approximately 230-degree panoramic photograph of ESO’s Very Large Telescope (VLT), taken by ESO Photo Ambassador Gerhard Hüdepohl, gives us an inspiring view of a slice of the sky, encompassing both our nearest celestial neighbour and star clusters hundreds of light-years away. The VLT’s four large Unit Telescopes dominate the foreground. With gigantic mirrors 8.2 metres across, they allow us to peer into space and see things four billion times fainter than we can see with our eyes alone. Also visible are the round enclosures of the four 1.8-metre Auxiliary Telescopes, one to the left of the Unit Telescopes and three to the right. This observatory has an excellent location, on Cerro Paranal in the Chilean Atacama Desert. It is so high, at 2600 metres altitude, that what looks like the rippling ocean to the west, on the left of the image, is in fact the cloud layer below ...
potw1122 — Picture of the Week
European Antennas Under Construction
30 May 2011: This is a helicopter view of the Atacama Large Millimeter/submillimeter Array (ALMA) Operations Support Facility (OSF) site. In the foreground is the AEM Consortium’s [1] facility where the European antennas are assembled and tested. Seven of the 25 European antennas can be seen, pointing towards the sky. More parts, including a receiver cabin and antenna base, await the next assembly. Each antenna has a dish 12 metres in diameter, and weighs about 95 tonnes. Once an antenna is assembled and ready, it is handed over to the ALMA project and moved to the nearby OSF technical area, which is the area in the background, where more antennas can be seen. Here, it is integrated into the rest of the observatory’s systems. Finally, after further tests by the ALMA team, it is moved from the 2900 metres high OSF to its workplace, the Array Operation Site (AOS), located at an altitude ...
potw1121 — Picture of the Week
First 7-metre ALMA Antenna Handed Over to Observatory
23 May 2011: The first of twelve 7-metre antennas has been handed over to the Atacama Large Millimeter/submillimeter Array (ALMA) observatory in Chile. ALMA will have an array of fifty antennas with 12-metre diameter dishes, as well as a system known as the Atacama Compact Array (ACA), provided by Japan, of which this new 7-metre antenna is part. The ACA will have a total of twelve 7-metre dishes and four 12-metre dishes, and will be particularly important for ALMA’s observations of the broader structure in extended astronomical objects such as giant clouds of molecular gas.The 7-metre antenna is seen here at the ALMA Operations Support Facility (OSF), at an altitude of 2900 metres in the foothills of the Chilean Andes. These antennas are being provided by Japan through a contract with MELCO (Mitsubishi Electric Corporation).The antennas are manufactured in Japan, then disassembled and shipped to Chile. They are reassembled and tested at the ...
potw1120 — Picture of the Week
The Czech President’s Galaxy
16 May 2011: This new image of the spiral galaxy NGC 3244 was taken with the help of the President of the Czech Republic, Václav Klaus, during his visit to ESO’s Paranal Observatory [1], on the night of 6 April 2011. The Czech Republic joined ESO in 2007, and this was the first visit of the country’s President to an ESO site. This galaxy has attracted considerable interest from astronomers over the past nine months, thanks to the violent death of one of its stars, which was discovered on 27 June 2010. This supernova explosion, now known as Supernova 2010ev (SN 2010ev), is still visible as the — now faint — blue dot nestled within one of the thick spiral arms just to the left of the galaxy’s nucleus. To the right of  the galaxy, an unremarkable foreground star in our own Milky Way, TYC 7713-527-1, shines brightly enough to catch our attention. Although ...
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