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The Antarctic Plateau is considered to be the best ground-based astronomical site on Earth. Compared with other middle latitude observatories, the telescopes located in Antarctica have unique advantages in seeing a large fraction of clear nights, continuous observing window in the polar night, and so on. China has operated several generations of telescopes in Antarctica, but has not yet achieved multicolour simultaneous observation with tracking. Multi-band Survey Telescope (MST) is the first multicolour simultaneous survey telescope in Antarctica. It adopts a Newtonian telescope structure which is different from other Antarctic telescopes and is matched with a new alignment scheme suitable for the harsh environment of Antarctica. In addition, MST is equipped with a defrosting indium tin oxide (ITO) window and a high-precision equatorial mount. This paper introduces the optical design, mechanical structure, and analysis of the actual operation of MST in Antarctica. Since March 2022, MST has been carrying out the observation normally in Zhongshan Station, and the operation of MST has provided a new experience for the follow-up design and installation of Antarctic telescopes. We plan to further optimize the design and manufacture of MST, and develop it as a standard model of small-aperture Antarctic telescopes for space debris observations and time-domain surveys.

The point spread function (PSF) reflects states of a telescope and plays an important role in development of data processing methods, such as PSF based astrometry, photometry and image restoration. However, for wide field small aperture telescopes (WFSATs), estimating PSF in any position of the whole field of view is hard, because aberrations induced by the optical system are quite complex and the signal to noise ratio of star images is often too low for PSF estimation. In this paper, we further develop our deep neural network (DNN) based PSF modelling method and show its applications in PSF estimation. During the telescope alignment and testing stage, our method collects system calibration data through modification of optical elements within engineering tolerances (tilting and decentering). Then we use these data to train a DNN (Tel--Net). After training, the Tel--Net can estimate PSF in any field of view from several discretely sampled star images. We use both simulated and experimental data to test performance of our method. The results show that the Tel--Net can successfully reconstruct PSFs of WFSATs of any states and in any positions of the FoV. Its results are significantly more precise than results obtained by the compared classic method - Inverse Distance Weight (IDW) interpolation. Our method provides foundations for developing of deep neural network based data processing methods for WFSATs, which require strong prior information of PSFs., Comment: Accepted by the MNRAS

We report on the initial results of seeing measurements at the Antarctic Taishan Station (ATS) using a differential image motion monitor observed in the visible at a height of 2.5 m above the snow surface, during the site-testing experiments carried out on 2014 January 13 and 15. The median seeing was found to be 0.73 arcsec and the 25th and 75th percentiles of the seeing cumulative distribution were 0.59 and 0.87 arcsec, respectively, with a minimum of ∼0.5 arcsec at ∼16:00–19:00 local time (UTC + 5). Such a seeing minimum has a good temporal association with the refractive index structure constant ($C_n^2$) minimum simultaneously observed at ATS. Interestingly, both temporal windows of $C_n^2$ and seeing minimum coincide with those of minimum temperature gradients ($\rm \sim 0\,^{\circ }C\,m^{-1}$), we had more than one month of continuous measurements of Cn2 and temperature gradients between 2013 December 30 and 2014 February 10. This suggests that high-quality seeing windows might be opened at ATS with the potential for astronomical activities, especially for solar observations.

Dome A is the highest point on the Antarctic Plateau, and the Chinese expedition team was the first to arrive there in 2005 January. It is an excellent site for astronomical observations. The Kunlun Dark Universe Survey Telescope (KDUST), a proposed next-generation Chinese Antarctic optical telescope, is currently being planned. KDUST is a coaxial three-mirror anastigmatic telescope with an entrance pupil diameter of 2.5 m and a field of view of 1.5 0 . The telescope should be fully aligned in order to achieve diffraction-limited image quality. Based on the current optical model for KDUST, in this study we describe a modified alignment metrology and give the preliminary results of numerical simulations. Using the acquisition of field-dependent aberrations, the algorithm, which is based on double Zernike polynomial decomposition and the least-squares fitting method, delivers a suitable set of corrections for resolvingmisalignments including themulti-axismotion of the secondary and tertiary mirrors. Moreover, the algorithm can also be used to calculate the primary mirror’s low-order figure errors mixing with the misalignments of the secondary mirror.