Southern African Large Telescope (SALT) Project: Progress and Status after Four Years

摘要

The Southern African Large Telescope (SALT) is a 10-m class telescope for optical/infrared astronomy based on the tilted Arecibo design first adopted by the Hobby Eberly Telescope. SALT is being constructed by a consortium consisting of 11 partners from six countries. SALT will enable a quantum leap in astronomical research capability in the African continent, where currently the largest telescope is a modest 1.9-m, dating to the 1940s. The SALT Project was approved in November 1999, the SALT project team started in January 2000, groundbreaking followed in September, the first mirror segment was installed in December 2002, and On-Sky Testing started in October 2003. SALT is due to start operations by 2005. The commissioning instrument has been developed by the South African Astronomical Observatory and the other first-light instrument is being developed by the University of Wisconsin-Madison. The major technical challenges in SALT are the alignment of the 91 identical spherical mirror segments, the position feedback of the prime focus tracker, and the dome seeing associated with large enclosures at a site with large daily thermal cycles. All of these issues were addressed thoroughly during the design phase, and first tests are showing very positive results in all these areas. This paper will summarize the international partnership in SALT and the management and organisation of the project and then address (1) the basic design, with emphasis on the technical challenges (2) the specified performance of SALT, (3) the progress and status of the project, including first light instruments.