December 11, 2009
A new telescope, the Visible and Infrared Survey Telescope for Astronomy (VISTA), has just started work at the European Southern Observatory's (ESO) Paranal Observatory and has made its first release of pictures. VISTA is a survey telescope working at infrared wavelengths, and it is the world's largest telescope dedicated to mapping the sky. Its large mirror, wide field of view, and sensitive detectors will reveal a completely new view of the southern sky. Spectacular new images of the Flame Nebula, the center of our Milky Way Galaxy, and the Fornax Galaxy Cluster show that it is working well.
VISTA is the latest telescope to be added to ESO's Paranal Observatory in the Atacama Desert of northern Chile. It is housed on the peak adjacent to the one hosting the ESO Very Large Telescope (VLT) and shares the same exceptional observing conditions. VISTA's main mirror is 13.5 feet (4.1 meters) across, and it is the most highly curved mirror of this size and quality ever made. Its deviations from a perfect surface are less than a few thousandths of the thickness of a human hair, and its construction and polishing presented formidable challenges.
VISTA was conceived and developed by a consortium of 18 universities in the United Kingdom and became an in-kind contribution to ESO as part of the UK's accession agreement. The telescope design and construction were managed by the Science and Technology Facilities Council's (STFC) UK Astronomy Technology Centre (UK ATC). Provisional acceptance of VISTA was formally granted by ESO at a ceremony at ESO's headquarters in Garching, Germany, December 10, 2009, and the telescope will now be operated by ESO.
"VISTA is a unique addition to ESO's observatory on Cerro Paranal," said Tim de Zeeuw, ESO's director general. "It will play a pioneering role in surveying the southern sky at infrared wavelengths and will find many interesting targets for further study by the VLT, ALMA, and the future European Extremely Large Telescope."
At the heart of VISTA is a 3-ton camera containing 16 special detectors sensitive to infrared light, with a combined total of 67 million pixels. Observing at wavelengths longer than those visible to the human eye allows VISTA to study objects that are otherwise impossible to see in visible light because they are either too cool, obscured by dust clouds, or because they are so far away that their light has been stretched beyond the visible range by the expansion of the universe. To avoid swamping the faint infrared radiation coming from space, the camera has to be cooled to -328° Fahrenheit (-200° Celsius) and is sealed with the largest infrared-transparent window ever made. The VISTA camera was designed and built by a consortium, including the Rutherford Appleton Laboratory, the UK ATC, and the University of Durham in the United Kingdom.
Because VISTA is a large telescope that also has a large field of view, it can detect faint sources and also cover wide areas of sky quickly. Each VISTA image captures a section of sky covering about ten times the area of the full Moon, and it will be able to detect and catalog objects over the southern sky with a sensitivity that is 40 times greater than that achieved with earlier infrared sky surveys. This jump in observational power — comparable to the step in sensitivity from the unaided eye to Galileo's first telescope — will reveal vast numbers of new objects and allow the creation of far more complete inventories of rare and exotic objects in the southern sky.
"We're delighted to have been able to provide the astronomical community with the VISTA telescope," said Ian Robson, head of the UK ATC. "The exceptional quality of the scientific data is a tribute to all the scientists and engineers who were involved in this exciting and challenging project."
VISTA will spend almost all of its time mapping the southern sky in a systematic fashion. The telescope is embarking on six major sky surveys with different scientific goals over its first five years. One survey will cover the entire southern sky and others will be dedicated to smaller regions to be studied in greater detail. VISTA's surveys will help our understanding of the nature, distribution, and origin of known types of stars and galaxies, map the three-dimensional structure of our galaxy and the neighboring Magellanic Clouds, and help determine the relation between the structure of the universe and the mysterious dark energy and dark matter.
The huge data volumes will flow back into the ESO digital archive and will be processed into images and catalogs at data centers in the United Kingdom at the Universities of Cambridge and Edinburgh. All data will become public and be available to astronomers around the globe.