Queen Mary led survey telescope nears completion

The VISTA mirror

16 April 2008

The world’s newest and fastest survey telescope - a project led by Queen Mary, University of London scientists - is nearing completion.

VISTA [the Visible and Infrared Survey Telescope for Astronomy]’s 4.1 metre diameter primary mirror has been delivered to its new mountain top home at Cerro Paranal Observatory, Chile, where the telescope is being assembled at an altitude of 2518m, in the Atacama Desert.

Dr Will Sutherland, Project Scientist on VISTA from Queen Mary’s Astronomy Unit, explained: "The mirror had a difficult four-day journey, by air and by road, from Moscow, where it had been polished. It arrived in perfect condition and now that it has been coated, we will install the mirror in the telescope with a small test camera for about four weeks testing. We plan to install the main camera in June."

The VISTA 4.1 metre diameter primary mirror is the most strongly curved large mirror ever polished to such a precise and exacting surface accuracy - deviations from a perfect surface of less than 1/3000th of the thickness of a human hair.

On arrival at Cerro Paranal it was safely craned into the telescope dome where it was washed and coated with a thin layer of protected silver in the facility’s coating plant. Silver is the best metal for the purpose since it reflects over 98 per cent of near-infrared light, better than the more commonly used aluminium. To date, the reflectivity produced by the silver coating- a relatively new venture - is well above that specified and exceeds all other telescopes.

VISTA will survey large areas of the southern sky at near infrared wavelengths (2 to 4 times the wavelength of visible light). It will help our understanding of the nature and distribution and origin of known types of stars and galaxies, map the 3-D structure of our galaxy, and help determine the relation between the 3-D structure of the universe and the mysterious 'dark energy' and dark matter'. Samples of objects will be followed up in detail with further observations by other telescopes and instruments such as the nearby Very Large Telescope (VLT).

Full scientific operations are due to start early next year. VISTA is being constructed for ESO (the Organisation for Astronomical Research in the Southern Hemisphere), and will form part of their Very Large Telescope (VLT) facility.

VISTA Project Manager Alistair McPherson from STFC’s UK Astronomy Technology Centre (UK ATC) travelled to Moscow to accompany the mirror on its journey to Chile. “Constructing modern telescopes brings together expertise from all over the world – such as a specialist mirror from Russia, for a British led telescope, project-managed from Edinburgh to be assembled in Chile! This has been a major milestone for VISTA. The precious mirror was loaded on to a plane in a special cradle that used tennis balls to cushion it from impact for its arduous journey across two continents.”

Professor Richard Wade, STFC Chief Operating Officer and President of ESO Council added: "The delivery of the last component of VISTA is a significant milestone and we are delighted with the progress made since the mirror arrived. Now astronomers can really look forward to being able to perform unparalleled observing of our Southern skies."

Ends

Images are available for download at: www.vista.ac.uk

For further information, please contact:

Siân Halkyard
Acting Head of Communications
Queen Mary, University of London
Tel: +44 (0) 20 7882 7454
email: s.halkyard@qmul.ac.uk

Notes to Editors:

Queen Mary, University of London

Queen Mary, University of London is one of the UK's leading research-focused higher education institutions with some 15,000 undergraduate and postgraduate students.

Amongst the largest of the colleges of the University of London, Queen Mary’s 3,000 staff deliver world class degree programmes and research across 21 academic departments and institutes, within three sectors: Science and Engineering; Humanities, Social Sciences and Laws; and the School of Medicine and Dentistry.

Queen Mary is ranked 11th in the UK according to the Guardian analysis of the 2008 Research Assessment Exercise, and has been described as ‘the biggest star among the research-intensive institutions’ by the Times Higher Education.

The College has a strong international reputation, with around 20 per cent of students coming from over 100 countries.

Queen Mary has an annual turnover of £220 million, research income worth £61 million, and generates employment and output worth £600 million to the UK economy each year.

Queen Mary, as a member of the 1994 Group of research-focused universities, has made a strategic commitment to the highest quality of research, but also to the best possible educational, cultural and social experience for its students. The College is unique amongst London's universities in being able to offer a completely integrated residential campus, with a 2,000-bed award-winning Student Village on its Mile End campus.

VISTA Consortium
VISTA is a £36 million project, funded by grants from the DTI's Joint Infrastructure Fund and the STFC to Queen Mary, University of London, the lead institute of the VISTA consortium. VISTA is project managed by STFC's UK Astronomy Technology Centre.
The VISTA consortium consists of: Queen Mary University of London, Queen’s University of Belfast, University of Birmingham, University of Cambridge, Cardiff University, University of Central Lancashire, University of Durham, The University of Edinburgh, University of Hertfordshire, Keele University, Leicester University, Liverpool John Moores University, University of Nottingham, University of Oxford, University of St Andrews, University of Southampton, University of Sussex, University College London. The delivery of VISTA is an in-kind payment as part of UK’s contribution to ESO.

VISTA Telescope
The VISTA telescope will have an extremely large field of view covering an area of the sky ten times the area of the moon in a single image. This makes it ideal for mapping large areas of the sky. Being a dedicated survey telescope, the optical design has been optimised for this purpose. The focusing power of the telescope is in the two mirrors, and three smaller lenses are used to give sharp images over the wide field of view. When it is completed it will be the world’s largest telescope dedicated to ground based survey work. Initially it will be equipped with the world’s largest infrared camera, and later could be augmented with an optical camera. The delivery of VISTA is an in-kind payment as part of UK’s contribution to ESO.

VISTA Science
VISTA is designed to be capable of making wide-field imaging observations from optical wavelengths out to 2.5 micrometres, thereby supporting a huge variety of existing projects from Solar System studies to cosmology; Measuring the Galaxy’s population of brown dwarf stars; Testing rival hypotheses for the nature of dark matter in the Galaxy; Constructing a 3D map that covers about 5% of the entire observable Universe; Measuring the rate of growth of galaxy clustering over the history of the Universe - a key prediction of cosmological theories; Looking for the most distant quasars at redshifts; Probing galaxy evolution by identifying and providing spectral energy distributions for the millions of galaxies expected to be detected by the next generation of mid-infrared, far-infrared and submillimetre space and ground-based surveys; Probing dark energy by identifying distant clusters of galaxies, in conjunction with Sunyaev-Zeldovich surveys from the South Pole and Atacama plateau; Mapping the structure of our Galaxy using near-infrared star counts over the whole available Galactic plane.

VISTA Telescope Facility
The Enclosure is a 19 metre diameter building which is designed to protect the telescope from the environment. The environmental management system maintains the internal atmosphere at the predicted night-time temperature to stop unwanted warm air currents causing blurring of the images. In addition, at night, the enclosure rotates in harmony with the telescope and includes a moon screen to stop moonlight impinging on the primary mirror and a wind screen and ventilation doors to control air flow throughout the observing night.

VISTA primary mirror
The VISTA primary mirror is 4.1 metres in diameter, with a 1.2 metre central hole for the camera; it is 17 centimetres thick and weighs nearly 5.5 tonnes.
It is made of a special ultra-low expansion glass-ceramic called Zerodur, from Schott Glas in Germany, and has been polished to the precise shape (a hyperboloid) by LZOS in Moscow; this polishing process has taken nearly two years.

Science and Technology Facilities Council
The Science and Technology Facilities Council ensures the UK retains its leading place on the world stage by delivering world class science; accessing and hosting international facilities; developing innovative technologies; and increasing the socio-economic impact of its research through effective knowledge exchange partnerships.

The Council has a broad science portfolio including Astronomy, Particle Physics, Particle Astrophysics, Nuclear Physics, Space Science, Synchrotron Radiation, Neutron Sources and High Power Lasers. In addition the Council manages and operates three internationally renowned laboratories:

•    The Rutherford Appleton Laboratory, Oxfordshire
•    The Daresbury Laboratory, Cheshire
•    The UK Astronomy Technology Centre, Edinburgh

The Council gives researchers access to world class facilities and funds the UK membership of international bodies such as the European Laboratory for Particle Physics (CERN), the Institute Laue Langevin (ILL), European Synchrotron Radiation Facility (ESRF), the European organisation for Astronomical Research in the Southern Hemisphere (ESO) and the European Space Agency (ESA). It also contributes money for the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, and the MERLIN/VLBI National Facility, which includes the Lovell Telescope at Jodrell Bank Observatory.

The Council distributes public money from the Government to support scientific research. Between 2007 and 2008 the STFC will invest £678 million.

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