Visible and infrared survey telescope for astronomy: Overview

We give an overview of the current status of the VISTA (Visible and Infrared Survey Telescope for Astronomy) project to build a 4-m wide field survey telescope to be operated by ESO (the European Southern Observatory) at the Cerro Paranal Observatory in Chile. First light in 2006 will be with the Infrared (J, H, K-s) Camera with a 1.65 degrees diameter field of view able to accommodate sixteen 2k x 2k IR detectors with 0.34" pixel size. Some motivations driving the choice of site, current design, and operational mode are discussed. We outline some innovative features of the system, which were necessary to deal with, or arose from, the very large field of view, including a cold baffle (rather than cold stop) in the IR camera, lack of traditional telescope focus, f/1 primary mirror, thermal control of the IR camera etc. These are cross-referenced to more detailed analyses by members of the VISTA Project Office team presented at this meeting. Estimated IR performance for VISTA is given. The scientific gains from adding the 2.1 degrees field of view Visible Camera when funds become available are stressed. The problems of processing 0.4TB of survey data acquired each night are discussed.