When the UK joined the European Southern Observatory in 2002, part of the joining fee was an IR survey telescope being developed by a consortium of 18 UK universities (see Physics Today, February 2008, page 25). Built on the mountain peak adjacent to ESO’s Very Large Telescope in Chile’s Atacama Desert, the Visible and Infrared Survey Telescope for Astronomy was provisionally accepted by ESO last December and is now being operated by ESO.
VISTA boasts a 4.1-meter main mirror and 16 IR detectors sensitive to wavelengths between 0.84 and 2.5 µm. To prevent the faint incoming IR signal from being drowned out by blackbody radiation from the telescope itself, the detectors and filters are housed in a cryostat and kept at 72 K by circulating liquid nitrogen. The detectors’ combined 67 million pixels over a field of view 1.65° in diameter are anticipated to produce 300 GB of...
