10th anniversary of VLT First Light The Messenger The ground layer seeing on Paranal HAWK-I Science Verification The emission nebula around Antares No. 132 – June 2008 –June 132 No. The Organisation The Perfect Machine Tim de Zeeuw a ground­based spectroscopic comple­ thousand each semester, 800 of which (ESO Director General) ment to the Hubble Space Telescope. are for Paranal. The User Portal has Italy and Switzerland had joined ESO in about 4 000 registered users and 1981, enabling the construction of the the archive contains 74 TB of data and This issue of the Messenger marks the 3.5­m New Technology Telescope with advanced data products. tenth anniversary of first light of the Very pioneering advances in active optics, Large Telescope. It is an excellent occa­ crucial for the next step: the construction sion to look at the broader implications of the Very Large Telescope, which Winning strategy of the VLT’s success and to consider the received the green light from Council in next steps. 1987 and was built on Cerro Paranal in The VLT opened for business some five the Atacama desert between Antofagasta years after the Keck telescopes, but the and Taltal in Northern Chile. The 8.1­m decision to take the time to build a fully Mission Gemini telescopes and the 8.3­m Subaru integrated system, consisting of four telescope were constructed on a similar 8.2­m telescopes and providing a dozen ESO’s mission is to enable scientific dis­ time scale, while the Large Binocular Tele­ foci for a carefully thought­out comple­ coveries by constructing and operating scope and the Gran Telescopio Canarias ment of instruments together with four powerful observational facilities that are now starting operations. 1.8­m Auxiliary Telescopes for the inter­ are beyond the capabilities of individual ferometer, was the right one. The combi­ member states. This principle was under­ The VLT was designed from the start as nation of a long­term adequately­funded stood right at the start in 1962, when an integrated system of four 8.2­m tele­ instrument and technology development Belgium, France, Germany, Sweden and scopes, including the possibility to com­ plan, with an approach where most of the Netherlands created ESO (with bine the light from individual telescopes the instruments were built in collaboration Denmark joining in 1967) to build a large for optical interferometry, enabling stu­ with institutions in the member states, telescope in the South. The main moti­ pendous spatial resolution. First light on with in­kind contributions in labour com­ vation was the need to be able to com­ Antu occurred in May 1998, with Kueyen, pensated by guaranteed observing time, pete scientifically with astronomers in Melipal and Yepun following soon after. has created the most advanced ground­ California who had access to large private Most of the VLT and VLTI instruments based optical observatory in the world. telescopes, most notably the 5­m Hale were built in close collaboration with insti­ The operations model distinguishes visi­ telescope on Mount Palomar, known as tutes in the member states. The entire tor and service mode, and provides the ‘Big Eye’, and considered by many first­generation instrument suite was com­ world­leading observing efficiency on a to be ‘The Perfect Machine’ of its time. In pleted in 2007 with the commissioning site where nearly 90 % of the nights are the United States of America, the same of CRIRES. The Paranal arsenal includes clear. All of this was made possible by the motivation had already led in 1957 to the turnkey adaptive optics systems and motivation of ESO staff members to build, creation of AURA, the Association of a rapid­response mode to react to fast operate and support the best possible Universities for Research in Astronomy, transient events. Recently, the near­ observatory. As a result, the VLT is argua­ which resulted in the Kitt Peak and Cerro infrared imager HAWK­I was added as a bly the natural successor of the ‘Perfect Tololo Observatories, each including a ‘generation­1.5’ instrument. Machine’ on Mount Palomar. Our 2007 4­m telescope and supported by the Visiting Committee, chaired by Professor National Science Foundation. In Europe The VLT and VLTI have contributed to all Günther Hasinger, stated it thus: “ESO the ESO mission resulted in the con­ areas of astronomy, including the nature has become the premier observatory for struction of the La Silla Observatory north of dark matter and dark energy, the ex­ optical­infrared astronomy on a world­ of La Serena in Chile, operating a fleet treme physics of gamma­ray bursts and wide basis.” of telescopes, with the 3.6­m as flagship. supernovae, the formation, structure and evolution of galaxies, the properties The stunning scientific success of the VLT of super­massive black holes in galactic attracted new member states to ESO. The Very Large Telescope nuclei, in particular the one in the Galac­ In the past decade Portugal joined (after tic Centre, of star clusters and stellar a ten­year associate status), followed by By the early 1980’s there were half­a­ populations, of the interstellar and inter­ the United Kingdom, Finland, Spain and dozen observatories with 4­m­class tele­ galactic medium, the formation of stars the Czech Republic. At the time of writ­ scopes available to astronomers world­ and planets, the properties of exo­ ing it looks likely that Austria will join later wide, La Silla being one of them. Plans planets, and of Solar System objects. The this year (see text of Press Release on were being drawn­up to construct much output in terms of refereed research page 5). These countries are drawn to more powerful telescopes with primary papers was 469 in 2007 alone, bring­ ESO because of the unique observing mirrors in the 8–10­m range. The Keck ing the total since first light to over 2 200, opportunities and by the possibility to be Foundation enabled the California Insti­ with the annual rate still increasing. involved in a coherent long­term pro­ tute of Technology and the University of gramme involving the design, construc­ California to build twin 10­m telescopes The total number of observing proposals tion and operation of future world­class on Mauna Kea, obtaining first light in for ESO facilities has doubled in the past ground­based facilities for astronomy. the early nineties, providing, in particular, decade, and now approaches nearly a As their annual contribution and entrance 2 The Messenger 132 – June 2008 The VLT as it is today with four Unit Telescopes and four Auxiliary Tele­ scopes. Photo: H. H. Heyer, ESO fee is added to ESO’s income, the acces­ 5 050­m altitude on Chajnantor east of ence exploitation, building on expertise sion of new member states also enables San Pedro de Atacama in northern Chile. with existing sub­millimetre telescopes, new projects. ALMA evolved from separate regional including APEX, and on science to plans to a global partnership between be done with the 3.5­m Herschel Space Europe, North America (USA and Can­ Obser vatory, which ESA expects to The next steps ada) and East Asia (Japan and Taiwan), launch in 2009. with ESO representing Europe. Partici­ The VLT will continue to increase in pation in ALMA expands ESO’s activities The next world­class ground­based facil­ power over the next decade. X­Shooter into a wavelength regime often associ­ ity is the European Extremely Large will come on line this year, with KMOS, ated with radio astronomy. The first step Telescope for the visible/infrared wave­ SPHERE and MUSE to follow, together has already been taken: ESO operates length regime. ESO is undertaking the with multiple laser guide stars, an adap­ APEX, a single­dish 12­m antenna for sub­ design study, in close collaboration with tive secondary mirror on Yepun, and millimetre astronomy located on Chajnan­ industry and institutes in the member one or more third­generation instruments, tor, in a partnership with Sweden and the states. The baseline design consists of a including an ultra­stable high­resolution Max­Planck­Gesellschaft. 42­m segmented primary mirror, an inno­ spectrograph at the combined focus vative five­mirror design, and adaptive (as foreseen in the original VLT design). ALMA construction is well underway. optics built into the telescope. The study The VLTI will be equipped with the sec­ ESO has delivered key components, draws on the entire expertise built up in ond­generation instruments GRAVITY including the Technical Building for the ESO and the member states over the and MATISSE, to be followed by VSI, the Observing Support Facility at 2 950 m, past decades, including lessons learned latter perhaps with two additional Auxil­ and two antenna transporters (see the from ALMA construction. The aim is to iary Telescopes, if external funding can article on page 23). Institutes in the be ready for a construction start in 2010, be found. member states are providing the Band 7 so that there is an opportunity for over­ and Band 9 high­frequency receivers lap with the James Webb Space Tele­ VISTA and the VST are expected to start and front­end integration for the 66 ALMA scope, which is the next NASA/ESA/CSA regular operations next year with a five­ antennas. The 25 12­m antennas to be flagship facility. year programme of coherent public sur­ delivered by European industry are be­ veys led by international teams. These hind schedule, with the first one arriving This combined programme is ambitious, surveys are performed together with data in Chile in the first half of 2009, where but achievable by building on the ‘VLT centres in the member states, coordi­ Japan and North America already have model’ in which high­quality staff carries nated by ESO.