The site testing shows that Antarctic Dome A is one of the best site on earth for astronomical observations, for wavelength ranging from visible to infrared and sub-millimeter. Continuous observation for nearly four months in polar nights makes Dome A quite suitable for time domain astronomy. In the past decade CCAA already led a series of Antarctic astronomy activities and telescope projects which will be introduced in this paper. The first generation telescope is Chinese Small Telescope Array known as CSTAR, which was composed of four identical telescopes with 145mm entrance pupil, 20 square degrees FOV and different filters, all pointing to the celestial South Point, mainly used for variable stars detection and site testing. The telescope was deployed in Dome A in Jan. 2008, and followed by automatic observations for four consecutive winters. Three Antarctic Survey Telescopes (AST3) is the second generation telescope capable of pointing and tracking in very low temperature, with 500mm entrance pupil, 8.5 square degree FOV. AST3-1 and AST3-2 were respectively mounted on Dome A in Jan. 2012 and 2015, fully remotely controlled for supernovae survey and exoplanets searching. In Aug. 2017, AST3-2 successfully detected the optical counterpart of LIGO Source GW 170817. Now AST3-3 is under development for both optical and near infrared sky survey by matching different cameras. Based on the experience of the above smaller sized optical telescopes, the 2.5m Kunlun Dark Universe Survey Telescope (KDUST) was proposed for high resolution imaging over wide field of view. Currently the KDUST proposal was submitted to the government and waiting for project review.
The Maunakea Spectroscopic Explorer is designed to be the largest non-ELT optical/NIR astronomical telescope, and will be a fully dedicated facility for multi-object spectroscopy over a broad range of spectral resolutions. The MSE design has progressed from feasibility concept into its current baseline design where the system configuration of main systems such as telescope, enclosure, summit facilities and instrument are fully defined. This paper will describe the engineering development of the main systems, and discuss the trade studies to determine the optimal telescope and multiplexing designs and how their findings are incorporated in the current baseline design.
A new type Stressed Mirror Polishing method using annular polishing machine is developed in NIAOT. It provides good efficiency for the massive production of off-axis segments for the extremely large telescope because 3 or more pieces of segment can be polished simultaneously on a AP machine. With an annular polishing machine with 3.6m diameter, two scale-down TMT segments have been polished. Both 2 segments are Φ1100mm in diameter, with the vertex radius of curvature of 60m and aspheric constant K=-1.000953. The off-axis distances (OAD) are 8m and 12m respectively. After SMAP process, the acceptable surface accuracy can be reached, which is 1.12μm/0.23μm of PV/RMS value for the segment with 8m OAD, and 1.22 μm/0.26 μm for another one.
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.
Extremely large telescopes with more and more large apertures are pursued, proposed and constructed by astronomers and technicians all over the world in the coming next years to satisfy the great demand of scientific progress. Segmented mirror active optics is the most important technology to co-phase the large primary for optically perfect segmentation. Based the experimental platform and test work in Nanjing Institute of Astronomical Optics and Technology in China, we introduce the latest co-phasing progress on fine segment support, edge sensor and close-loop co-phasing correction in China in this paper. Finally some conclusions are given based on the test results.
Chinese Antarctic Observatory has been listed as National large research infrastructure during twelfth five-year plan. Kunlun Dark Universe Survey Telescope, one of two major facility of Chinese Antarctic Observatory, is a 2.5-meter optic/infrared telescope and will be built at the Chinese Antarctic Kunlun Station. It is intended to take advantage of the exceptional seeing conditions, as well as the low temperature reducing background for infrared observations. KDUST will adopt an innovative optical system, which can deliver very good image quality over a 2 square degree flat field of view. All of parts of it have been designed carefully to endure the extremely harsh environment. KDUST will be perched on a 14.5-meter-high tower to lift it above the turbulence layer. In this paper, preliminary design and key technology pre-research of KDUST will be introduced.
Dome A has been considered as one of the best observation sites on the earth. The First
AST3(three Antarctic Survey Telescopes) is on its way to Dome A by the 28th Chinese National
Antarctic research expedition. It will be the largest Optic telescope in Dome A after assembling and
testing in this austral summer. Firstly, this paper reports the method of collecting the vibration and
shock data from ShangHai to Dome A and analyses the data. Secondly, the package cushioning design
of the first AST3 is introduced in this paper according to the vibration and shock data. Finally, the
paper introduces the result of the dynamics analysis of the design and a test was done to verify the
performance of the package cushioning design. The dynamics analysis and the test indicate that the
package cushioning design can meet the demand of the Antarctic inland transportation.
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.
Nigel is a fiber-fed UV/visible grating spectrograph with a thermoelectrically-cooled 256×1024 pixel CCD camera,
designed to measure the twilight and night sky brightness from 300nm to 850 nm. Nigel has three pairs of fibers,
each with a field-of-view with an angular diameter of 25 degrees, pointing in three fixed positions towards the
sky. The bare fibers are exposed to the sky with no additional optics. The instrument was deployed at Dome A,
Antarctica in January 2009 as part of the PLATO (PLATeau Observatory) robotic observatory. During the 2009
winter, Nigel made approximately six months of continuous observations of the sky, with typically 104 deadtime
between exposures. The resulting spectra provide quantitative information on the sky brightness, the auroral
contribution, and the water vapour content of the atmosphere. We present details of the design, construction
and calibration of the Nigel spectrometer, as well some sample spectra from a preliminary analysis.
Prelimenary site testing led by Chinese Center of Antarctic Astronomy (CCAA) shows that the highest point of the
Antarctic Plateau Dome A has very clear sky, good seeing, slow wind, low boundary layer and very low precipitable
water vapour which make it the best site on earth for optical/IR and sub-mm observations. Chinese Small Telescope
ARray (CSTAR) was installed at Dome A in 2008 and have automatically observed for about 3 antarctic winters. The
three Antarctic Schmidt telescopes(AST3) with entrance pupil diameter 500mm are the second antarctic project
proposed by CCAA and the first AST are being constructed in NIAOT now which is planned to be mounted on Dome A
at the beginning of 2011. All the tracking components were tested in the low temperature chamber and an adaptive
defrosting method is designed to prevent the frost building up on the schmidt plate.
Snodar is a high resolution acoustic radar designed specifically for profiling the atmospheric boundary layer on the high
Antarctic plateau. Snodar profiles the atmospheric temperature structure function constant to a vertical resolution of 1 m
or better with a minimum sample height of 8 m. The maximum sampling height is dependent on atmospheric conditions
but is typically at least 100 m. Snodar uses a unique in-situ intensity calibration method that allows the instrument to be
autonomously recalibrated throughout the year. The instrument is initially intensity calibrated against tower-mounted
differential microthermal sensors. A calibration sphere is located in the near-field of the antenna to provide a fixed echo
of known intensity, allowing the instrument to be continuously re-calibrated once deployed. This allows snow
accumulation, transducer wear and system changes due to temperature to be monitored. Year-round power and
communications are provided by the PLATO facility. This allows processed data to be downloaded every 6 hours while
raw data is stored on-site for collection the following summer. Over 4 million processed samples have been downloaded
through PLATO to date. We present signal attenuation from accumulation of snow and ice on Snodar's parabolic
reflector during the 2009 at Dome A.
The high altitude Antarctic sites of Dome A and the South Pole offer intriguing locations for future large scale optical
astronomical Observatories. The Gattini project was created to measure the optical sky brightness, large area cloud cover
and aurora of the winter-time sky above such high altitude Antarctic sites. The Gattini- DomeA camera was installed on
the PLATO instrument module as part of the Chinese-led traverse to the highest point on the Antarctic plateau in January
2008. This single automated wide field camera contains a suite of Bessel photometric filters (B, V, R) and a long-pass
red filter for the detection and monitoring of OH emission. We have in hand one complete winter-time dataset (2009)
from the camera that was recently returned in April 2010.
The Gattini-South Pole UV camera is a wide-field optical camera that in 2011 will measure for the first time the UV
properties of the winter-time sky above the South Pole dark sector. This unique dataset will consist of frequent images
taken in both broadband U and B filters in addition to high resolution (R~5000) long slit spectroscopy over a narrow
bandwidth of the central field. The camera is a proof of concept for the 2m-class Antarctic Cosmic Web Imager
telescope, a dedicated experiment to directly detect and map the redshifted lyman alpha fluorescence or Cosmic Web
emission we believe possible due to the unique geographical qualities of the site.
We present the current status of both projects.
For continuous observation at locations that are inhospitable for humans, the desirability of autonomous observatories is
self evident. PLATO, the 'PLATeau Observatory' was designed to host an easily configurable instrument suite in the
extremely cold conditions on the Antarctic plateau, and can provide up to 1 kW of power for the instruments. Powered
by jet fuel and the Sun, PLATO and its instruments have been taking nearly uninterrupted astronomical science and sitetesting
data at Dome A, the coldest, highest and driest location<sup>1</sup> on the Antarctic Plateau, since their deployment by the
24th Chinese expedition team in January 2008. At the time of writing, PLATO has delivered a total uptime of 730 days.
Following a servicing mission by the 25th Chinese expedition team in 2008-9, PLATO has achieved 100% up-time (520
days) and has been in continuous contact with the rest of the world via its Iridium satellite modems. This paper discusses
the performance of the observatory itself, assesses the sources of energy and dissects how the energy is divided between
the core observatory functions of instrument power, heating, control and communication.
Dome C and A of the Antarctic plateau is considered to be the best astronomical site on the earth because of extremely
cold, dry weather, low wind speed and atmospheric turbulence overhead. CSTAR (Chinese Small Telescope ARray),
which is composed of four small telescopes with 100mm clear aperture, has been accomplished in August and shipped
to Antarctic at November 2007. Then, from the Zhongshan station, Chinese traverse team sledged it by snow tractor to
Dome A through about 20 days hard trip and erected in January 2008. In this paper, the vibration proof design of
packing box of CSTAR is introduced based on vibration theory and the analysis of power spectrum density is done to
verify parameter selection. Finally, transport experiment is done to prove that packing box is suitable for the inclement
and various transport condition.
Chinese first arrived in Antarctic Dome A in Jan. 2005 where is widely predicted to be a better astronomical site than
Dome C where have a median seeing of 0.27arcsec above 30m from the ground. This paper introduces the first Chinese
Antarctic telescope for Dome A (CSTAR) which is composed of four identical telescopes, with entrance pupil 145 mm,
20 square degree FOV and four different filters g, r, i and open band. CSTAR is mainly used for variable stars detection,
measurement of atmosphere extinction, sky background and cloud coverage. Now CSTAR has been successfully
deployed on Antarctic Dome A by the 24th Chinese expedition team in Jan. 2008. It has started automatic observation
since March 20, 2008 and will continuously observe the south area for the whole winter time. The limited magnitude
observed is about 16.5<sup>m</sup> with 20 seconds exposure time. CSTARS's success is a treasurable experience and we can
benefit a lot for our big telescope plans, including our three ongoing 500mm Antarctic Schmidt telescopes (AST3).
Over a decade of site testing in Antarctica has shown that both South Pole and Dome C are exceptional sites for
astronomy, with certain atmospheric conditions superior to those at existing mid-latitude sites. However, the highest
point on the Antarctic plateau, Dome A, is expected to experience colder atmospheric temperatures, lower wind speeds,
and a turbulent boundary layer that is confined closer to the ground. The Polar Research Institute of China, who were the
first to visit the Dome A site in January 2005, plan to establish a permanently manned station there within the next
decade. As part of this process they conducted a second expedition to Dome A, arriving via overland traverse in January
2008. This traverse involved the delivery and installation of the PLATeau Observatory (PLATO). PLATO is an
automated self-powered astrophysical site testing observatory, developed by the University of New South Wales. A
number of international institutions have contributed site testing instruments measuring turbulence, optical sky
background, and sub-millimetre transparency. In addition, a set of science instruments are providing wide-field high time
resolution optical photometry and terahertz imaging of the Galaxy. We present here an overview of the PLATO system
design and instrumentation suite.
Since Chinese scientific expedition team first arrived Dome A in 10, Jan., 2005, meteorological data have been obtained
from this highest point of the Antarctic Plateau. It is likely that Dome A can be the best site for ground-based
astronomy. Chinese astronomy community, led by Chinese Center for Antarctic Astronomy, is part of an international
effort to survey Dome A for astronomical observations, and has built 4 small telescopes (CSTAR) which have been
installed at Dome A in 2008. We report here a more ambitious goal: three Antarctic Schmidt telescopes (AST3) with
aperture 50 cm each and the modified Schmidt system (about half shorter tube comparing with normal one) are being
constructed, and will be installed for observation at Dome A in Jan., 2010. AST3 will be used for the discovery and
exploration of astrophysical transients. This paper presents the technical configuration, design of these Schmidt
telescopes, and study on technical challenges for telescope at such a special place with extremely environment on the
With the development of large segmented-mirror telescopes, the segmented-mirror support technology has been researched and used widely and successfully. Besides the sub-mirror cell used to support single sub-mirror, the whole truss for supporting all the sub-mirrors also has been developed gradually. Different from the backup structure of radio telescope, the truss of optical segmented-mirror telescope needs not only huge spatial dimension but also high precision and long-term stability. In this paper, the spatial topology of truss and selection of node type have been introduced, at
the same time, through the design and assembling of the primary mirror truss of LAMOST, some experiences have been also shared.
Mirror support system of astronomical telescope is composed of axial support and lateral support. In traditional telescope, because the contribution of lateral support to surface distortion is less than axial support, there are usually few lateral support methods such as lever counterweight, hydrostatic pressure and steel strap in the past. With increase of diameter to thickness ratio and use of strongly concave mirrors, lateral support is becoming more complicated and important than before. At the same time, application of segmented mirror make it impossible to support periphery of mirror, so, some new schemes have been designed to meet requirement of large segmented-mirror telescope. This paper introduces some classic and recent methods of lateral support for large telescope and gives some results of finite element analysis.
The thirty-seven one meter class mirror segments which comprise the LAMOST primary mirror need precision support and cell to meet the demand of optics surface figure. Because true ZERODUR glass mirror has had the final design drawing that has been slight different from the former one, a modified sub-mirror finite element model and re-analysis have considered many new factors including the anti-drop groove, center blind hole and invar pad. At the same time, After a sub-cell prototype have been designed and manufactured, with a similar K9 glass mirror segment, the experiment of mirror figure testing is being conduct to verify sub-cell's performance and modify some detail. The support truss of primary mirror also has new scheme. This paper introduces the sub-cell prototype experiment, analysis of sub-mirror and new support truss.
LAMOST (The Large Sky Area Multi-object Fiber Spectroscopic Telescope) is a reflecting Schmidt telescope. There are two large segmented mirrors in LAMOST: One is the Schmidt plate M<sub>A</sub>, and the other is the spherical primary mirror M<sub>B</sub>. The dimension of M<sub>B</sub> is about 6.7m×6m and it is face down in 25°. M<sub>B</sub> is composed of 37 hexagonal sub-mirrors. During the observation, one should maintain the correct mirror figure for each sub-mirror and co-focus for all 37 sub-mirrors to obtain the good image, even it is an unconventional designed telescope without tracking movement on the primary mirror. This paper presents the design and the finite element analysis for the whole primary mirror support system, which includes the optimization of the mirror support points distribution, the design and the testing of the prototype of M<sub>B</sub> sub-cell, the structure analysis and the design of the mirror support truss.
The Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) is a national large scientific project in China at the beginning of this century. It is an unconventional designed modern optical telescope and has the both large field of view and large aperture. The spherical primary mirror M<sub>B</sub> in LAMOST is a segmented mirror with 37 sub-mirrors. The M<sub>B</sub> will be supported by a very stable truss structure and the mirror surface will be kept in a high optical accuracy. This paper presents the work on the finite element model of the truss structure of M<sub>B </sub>and gives the results of static and dynamic analysis with this model especially for the optimization of the higher stiffness and the lighter weight.