The Antarctic Survey Telescope-AST3 consists of three optical telescopes with 680mm primary mirror and 8 square degree field of view, mainly for observations of supernovas and extrasolar planets searching from Antarctic Dome A. The first two AST3 telescopes (AST3-1 and AST3-2) were successfully installed on Dome A by Chinese expedition team in Jan. 2012 and Jan. 2015 separately. Multi-anti-frost methods were designed for AST3-2 and the automatic observations are keeping on from March 2016. The best limited magnitude is 19.4m with exposure time 60s in G band. The third AST3 will have switchable interface for both optical camera and near infrared camera optimized for k dark band survey. Now the telescope is under development in NIAOT and the K-band camera is under development in AAO.
The preliminary site testing performed since the beginning of 2008 shows that Antarctic Dome A is an excellent astronomical site. The Chinese Antarctic optical telescopes CSTAR and the first Antarctic Survey Telescope AST3-1 has been in operation on Dome A, and several Antarctic telescopes are being developed and proposed. However, the harsh environment and manpower shortage make the in-situ alignment task difficult. The study will introduce the completed alignment work of AST3 and discuss an improved align metrology based on the previous treatments of the field dependent optical aberrations, as well as its application on Antarctic Bright Star Survey Telescope BSST.
The AST3 project consists of three large field of view survey telescopes with 680mm primary mirror, mainly for observations of supernovas and extrasolar planets searching from Antarctic Dome A where is very likely to be the best astronomical site on earth for astronomical observations from optical wavelength to thermal infrared and beyond, according to the four years site testing works by CCAA, UNSW and PRIC. The first AST3 was mounted on Dome A in Jan. 2012 and automatically run from March to May 2012. Based on the onsite winterization performance of the first AST3, some improvements such as the usage of high resolution encoders, defrosting method, better thermal control and easier onsite assembly et al were done for the second one. The winterization observation of AST3-2 in Mohe was carried on from Nov. 2013 to Apr. 2014, where is the most northern and coldest part of China with the lowest temperature around -50°. The technical modifications and testing observation results will be given in this paper. The third AST3 will be optimized from optical to thermal infrared aiming diffraction limited imaging with K band. Thus the whole AST3 project will be a good test bench for the development of future larger aperture optical/infrared Antarctic telescopes such as the proposed 2.5m Kunlun Dark Universe Survey Telescope project.
The preliminary site testing carried out since the beginning of 2008 shows the Antarctic Dome A is very likely to be the
best astronomical site on earth even better than Dome C and suitable for observations ranging from optical wavelength to
infrared and sub-millimeter. After the Chinese Small Telescope Array (CSTAR) which is composed of four small fixed
telescopes with diameter of 145mm and mounted on Dome A in 2008 for site testing and variable star monitor, three
Antarctic Survey Telescopes (AST3) were proposed for observations of supernovas and extrasolar planets searching.
AST3 is composed of 3 large field of view catadioptric telescopes with 500mm entrance diameter and G, R, I filter for
each. The telescopes can point and track autonomously along with a light and foldable dome to keep the snow and icing
build up. A precise auto-focusing mechanism is designed to make the telescope work at the right focus under large
temperature difference. The control and tracking components and assembly were successfully tested at from normal
temperature down to -80 Celsius degree. Testing observations of the first AST3 showed it can deliver good and uniform
images over the field of 8 square degrees. The first telescope was successfully mounted on Dome A in Jan. 2012 and the
automatic observations were started from Mar. 2012.