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ESO Releases First Images From The VLT Survey Telescope

June 8, 2011

VST and 268 megapixel OmegaCAM start work

The VLT Survey Telescope (VST), the latest addition to ESO’s Paranal Observatory, has made its first release of impressive images of the southern sky. The VST is a state-of-the-art 2.6-meter telescope, with the huge 268-megapixel camera OmegaCAM at its heart, which is designed to map the sky both quickly and with very fine image quality. It is a visible-light telescope that perfectly complements ESO’s VISTA infrared survey telescope. New images of the Omega Nebula and the globular cluster Omega Centauri demonstrate the VST’s power.

A New Telescope and Camera

The VLT Survey Telescope (VST) is the latest telescope to be added to ESO’s Paranal Observatory in the Atacama Desert of northern Chile. It is housed in an enclosure immediately adjacent to the four VLT Unit Telescopes on the summit of Cerro Paranal under the pristine skies of one of the best observing sites on Earth. The VST is a wide-field survey telescope with a field of view twice as broad as the full Moon. It is the largest telescope in the world designed to exclusively survey the sky in visible light. Over the next few years the VST and its camera OmegaCAM will make several very detailed surveys of the southern sky. All survey data will be made public.

“I am very pleased to see the impressive first images from the VST and OmegaCAM. The unique combination of the VST and the VISTA infrared survey telescope will allow many interesting objects to be identified for more detailed follow-up observations with the powerful telescopes of the VLT,” says Tim de Zeeuw, the ESO Director General.

“The VST project has overcome many difficulties but it is now repaying, with its excellent image quality, the expectations of the astronomical community and the efforts of the many people at INAF involved in its construction. I am very pleased to see the VST in operation,” adds Tommaso Maccacaro, the President of the Italian National Institute for Astrophysics (INAF).

The VST program is a joint venture between the INAF”“Osservatorio Astronomico di Capodimonte, Naples, Italy [1] and ESO. INAF has designed and built the telescope with the collaboration of leading Italian industries and ESO is responsible for the enclosure and the civil engineering works at the site. OmegaCAM, the VST’s camera, was designed and built by a consortium including institutes in the Netherlands, Germany and Italy [2] with major contributions from ESO. The new facility will be operated by ESO, which will also archive and distribute data from the telescope.

The VST is a state-of-the-art 2.6-meter aperture telescope with an active optics system to keep the mirrors perfectly positioned at all times. At its core, behind large lenses that ensure the best possible image quality [3], lies the 770 kg OmegaCAM camera, built around 32 CCD detectors [4], sealed in vacuum, that together create 268-megapixel images [5].

The First Images

Both the telescope and the camera have been designed to fully exploit the high quality skies at Paranal.

“The superb images now coming from VST and OmegaCAM are a tribute to the hard work of many groups around Europe over many years. We are now looking forward to a rich harvest of science and unexpected discoveries from the VST surveys,” adds Massimo Capaccioli, principal investigator of the VST project.

The first released image shows the spectacular star-forming region Messier 17, also known as the Omega Nebula or the Swan Nebula, as it has never been seen before. This dramatic region of gas, dust and hot young stars lies in the heart of the Milky Way in the constellation of Sagittarius (The Archer). The VST field of view is so large that the entire nebula, including its fainter outer parts, is captured “” and retains its superb sharpness across the entire image.

The second released image may be the best portrait of the globular star cluster Omega Centauri ever made. This is the largest globular cluster in the sky, but the very wide field of view of VST and OmegaCAM can encompass even the faint outer regions of this spectacular object. This view, which includes about 300 000 stars, demonstrates the excellent resolution of VST.

The Surveys

The VST will make three public surveys over the next five years [6]. The KIDS survey will image several regions of the sky away from the Milky Way. It will further the study of dark matter, dark energy and galaxy evolution, and find many new galaxy clusters and high-redshift quasars. The VST ATLAS survey will cover a larger area of sky and focus on understanding dark energy and supporting more detailed studies using the VLT and other telescopes. The third survey, VPHAS+, will image the central plane of the Milky Way to map the structure of the Galactic disc and its star formation history. VPHAS+ will yield a catalogue of around 500 million objects and will discover many new examples of unusual stars at all stages of their evolution.

The data volume produced by OmegaCAM will be large. About 30 terabytes of raw data will be produced per year and will flow back into data centers in Europe for processing [7]. A novel and sophisticated software system has been developed at Groningen and Naples to handle the very large data flow. The end products from the processing will be huge lists of the objects found, as well as images, and these will be made available to astronomers worldwide for scientific analysis.

“The combination of large field of view, excellent image quality, and the very efficient operations scheme of the VST will produce an enormous wealth of information that will advance many fields of astrophysics,” concludes Konrad Kuijken, head of the OmegaCAM consortium.

Notes

[1] The VST has been designed at the Astronomical Observatory of INAF at Capodimonte, Naples. All components apart from the main optics, which were supplied by the Russian firm LZOS, have been built by Italian industries. INAF has managed the construction and secured the assembly at the Paranal Observatory. This work was performed with the contribution of the project manager G. De Paris and the AIV manager D. Fierro, members of the INAF Department of National Projects, Monte Mario, Rome, Italy. The project manager of the current phase of commissioning is P. Schipani from INAF-Capodimonte Observatory. He was the former VST project engineer and leads a team mostly from the Naples and Padua Observatories. The VST-Tube software system to handle the data at Naples was developed by A. Grado.

[2] The OmegaCAM consortium is comprised of institutes in the Netherlands (NOVA, in particular the Kapteyn Institute / OmegaCEN Groningen and Leiden Observatory), Germany (in particular the university observatories of Munich, Göttingen and Bonn) and Italy (INAF, in particular the Padua and Naples Observatories). The ESO Optical Detector Team provides the detector system. OmegaCAM is headed by PI K. Kuijken (Groningen and Leiden University) and co-PI’s R. Bender (Munich USM/MPE) and E. Cappellaro (INAF, Osservatorio Astronomico di Padova), project management is done by B. Muschielok and R. Häfner (University Observatory of the Ludwig-Maximilians University Munich) and the data handling system, Astro-WISE, is developed by OmegaCEN-NOVA led by E.A. Valentijn (Groningen).

[3] The telescope optics also include correction for dispersion by the Earth’s atmosphere.

[4] The camera also contains extra CCDs, which work with the telescope’s systems to help control the guiding and active optics systems.

[5] To measure the colors of objects in the sky, different very large glass filters can be slid automatically in front of the detectors. Each filter is over 30 cm on a side and most have special coatings that ensure that very little light is lost. There is also a very large shutter consisting of two blades that can be used to block the light while the detectors are read out.

[6] More details about the VST public surveys are available at http://www.eso.org/sci/observing/policies/PublicSurveys/sciencePublicSurveys.html.

[7] The VST/OmegaCAM surveys will make use of a new, dedicated fast intercontinental data link between Paranal and Europe that was established with support from the European Union (eso1043).

More information

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organization in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious program focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organizing cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-meter European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Image 1: The first released VST image shows the spectacular star-forming region Messier 17, also known as the Omega Nebula or the Swan Nebula, as it has never been seen before. This vast region of gas, dust and hot young stars lies in the heart of the Milky Way in the constellation of Sagittarius (The Archer). The VST field of view is so large that the entire nebula, including its fainter outer parts, is captured “” and retains its superb sharpness across the entire image. The data were processed using the Astro-WISE software system developed by E.A. Valentijn and collaborators at Groningen and elsewhere. Credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute

Image 2: The second released VST image may be the best portrait of the globular star cluster Omega Centauri ever made. Omega Centauri, in the constellation of Centaurus (The Centaur), is the largest globular cluster in the sky, but the very wide field of view of VST and its powerful camera OmegaCAM can encompass even the faint outer regions of this spectacular object. This view includes about 300 000 stars. The data were processed using the VST-Tube system developed by A. Grado and collaborators at the INAF-Capodimonte Observatory. Credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: A. Grado/INAF-Capodimonte Observatory

Image 3: This view taken from the inside of the VST enclosure shows the telescope observing on a moonlit night. The telescope is pointing away from the camera and the OmegaCAM camera appears in the lower center of the image. It is attached below the main mirror of the telescope and includes the orange and red structures. Credit: ESO/INAF-VST/OmegaCAM/G. Lombardi

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