Telescopes and Instrumentation

First Release of Images from VISTA

The new ESO survey telescope VISTA such a low focal ratio, the figuring and tic, on the theme of formation and (the Visible and Infrared Survey Tele- polishing of the primary was a formidable very low mass and brown dwarfs scope for Astronomy) was recently task. The secondary is 1.24 metres in in the Orion region; and one extragalac- commissioned at Paranal and has just diameter. As a survey telescope it has tic, on the stellar halo in NGC 253. The released its first public images. only one instrument, a camera composed SV data will be processed using the of 16 2048 × 2048 infrared detectors. VISTA Data Flow System run jointly by the The Raytheon VIRGO HgCdTe detectors Cambridge Astronomical Survey Unit VISTA was conceived and developed by have 0.34-arcsecond pixels and a single (CASU) and the Wide Field Astronomy a consortium of 18 universities in the “pawprint” covers an area of 0.6 square Unit Edinburgh (WFAU), and the reduced United Kingdom led by Queen Mary, Uni- degrees. By combining six offset images, data will be publicly released. versity of London and became an in-kind a full field coverage of 1.5 × 1.0 degrees contribution to ESO as part of the UK’s is achieved. The camera was designed VISTA will be dedicated to large surveys accession agreement. The telescope is and built by a consortium including the and a five-year programme of six public described in Emerson et al. (2004, 2006). Rutherford Appleton Laboratory, the UK surveys has been assigned. Observations Project management for the telescope ATC and the University of Durham. Fig­- will begin soon. They range from surveys design and construction was the respon- ure 1 shows a view of the telescope with of variable stars in the , a sur- sibility of the Science and Technology the camera in the process of being re- vey of the Magellanic Clouds, a southern Facilities Council’s UK Astronomy Tech- moved. The camera has five broadband hemisphere survey and a large area nology Centre (STFC, UK ATC). Provi- filters Z, Y, J, H and Ks, with an option for ­ survey, and two deep small field sional acceptance of VISTA was formally user-provided filters. surveys. Details of these surveys can be granted by ESO at a ceremony at ESO found in Arnaboldi et al. (2007). Headquarters in Garching, Germany, The front cover shows a colour-compos- attended by representatives of Queen ite image of the dusty star-forming H ii References Mary, University of London and STFC on region NGC 2024 in the Orion Cloud re- 10 December 2009. VISTA will now be gion, called the Flame (image Arnaboldi, M. et al. 2007, The Messenger, 127, 28 operated by ESO. from the ESO press release). Figure 2 Emerson, J. P. et al. 2004, The Messenger, 117, 27 shows a 1 × 1.4 degree region of the Emerson, J. P. et al. 2006, The Messenger, 126, 41 VISTA has a 4.1-metre primary mirror with ­ , with NGC 1399 a 1.65 degree field of view. On account and NGC 1365 both visible. The VISTA Links of the speed of the primary (F/0.98), the science verification (SV) programme1 1 largest mirror to be manufactured with consists of two mini-surveys: one Galac- http://www.eso.org/sci/activities/vltsv/vista/index. html

Figure 1 (left). The VISTA infrared camera being removed to allow the primary mirror to be recoated in September 2009. Credit: ESO/G. Hüdepohl

Figure 2 (right). VISTA colour image (from Z, J and Ks filters) of the Fornax galaxy cluster. At the lower left is the barred-spiral galaxy NGC 1365 and to the upper right the central bright ellip- tical NGC 1399. The total exposure time per pixel was about 25 minutes.

2 The Messenger 138 – December 2009 Credit: ESO/J. Emerson/VISTA Acknowledgement: ­Cambridge Astronomical Survey Unit