orion nebula

MUSTMultiplexed Survey Telescope


The MUST team wins the group championship at the Tsinghua DoA Fun Sports Meeting

On October 19th, 2023, the Department of Astronomy, Tsinghua University held a unique fun sports meeting. Approximately 90 faculty and students actively participated and were divided into 9 groups to compete in a series of exciting sports events. The atmosphere throughout the sports meeting was enthusiastic, and members of each group participated actively in the competitions. Everyone invested their efforts, demonstrating high-level athletic skills and a spirit of teamwork, which garnered warm applause from the audience. After entertaining and intense competitions, the MUST team ultimately emerged as the first-place winner due to its outstanding performance. Collective strength was fully demonstrated during the games, and the team’s members’ coordinated collaboration earned recognition from other groups. The members of the MUST team feel immensely proud and honored for winning the championship. Team captain Lao Junsen expressed sincere gratitude to all the members for their hard work and selfless dedication, stating that the success of the sports meet was a result of teamwork and cooperation. He hopes that this spirit of unity and cooperation will enhance the team’s cohesion in their work. The fun sports meeting not only improved participants’ physical fitness but also further ignited their enthusiasm for sports and raised their awareness of teamwork. The successful organization of the sports meet provided a platform for faculty and students to showcase their individual skills and teamwork abilities, and also offered an opportunity for mutual exchange and deepening friendships between participants. ![Professor Mao Shude, the head of the Department of Astronomy and the project leader of MUST, giving a speech](https://must.astro.tsinghua.edu.cn/admin/uploads/20231115_143200_2f16deff1b.jpg) ![Warm-up activity](https://must.astro.tsinghua.edu.cn/admin/uploads/2ff82d19_a8b1_48fc_bc88_a6b1533662c0_45aa2cd42d.png) ![Scene of the fun sports meeting](https://must.astro.tsinghua.edu.cn/admin/uploads/20231115_143217_b28e2b09ad.jpg) ![Professor Mao Shude shooting basketball](https://must.astro.tsinghua.edu.cn/admin/uploads/240_A9095_f2bed33605.png) ![Professor Cai Zheng shooting basketball](https://must.astro.tsinghua.edu.cn/admin/uploads/63d54987_d245_4932_bfa8_4d8311ba9ece_c03cde8a67.png) ![MUST team participating in the “peanut-grabbing” relay race](https://must.astro.tsinghua.edu.cn/admin/uploads/dc159779_10c5_4153_86db_c4c4051ea513_2ead34d3bb.png) ![MUST team receiving the championship prize](https://must.astro.tsinghua.edu.cn/admin/uploads/c7dbfc2d_4b5d_4203_a751_8749cbac3dc4_084c5588fe.png)


Professor Stephen Alan Shectman, a Fellow of the National Academy of Sciences of the United States, Visits Tsinghua University to Guide the Work of the MUST Team

From October 7 to November 3, 2023, Professor Stephen Alan Shectman, an outstanding visiting professor at Tsinghua University and a Fellow of the National Academy of Sciences of the United States , visited Tsinghua. During the nearly one-month period, Steve had in-depth discussions and communications with members of each subsystem of the MUST team, sharing his experience from working on the Magellan Telescope project. He maintained a candid and proactive attitude in technical exchanges. Whether discussing theoretical issues or optimizing technical solutions, Steve always enthusiastically provided assistance and guidance to the team. Despite the differing opinions among team members on technical approaches, Steve always respected others’ opinions and candidly shared his own thoughts. He was willing to listen to different views and showed understanding and support for the team’s decisions, which were made after careful consideration. When interacting with young team members, Steve taught them how to wholeheartedly engage in scientific engineering and encouraged everyone to unite and cooperate with each other. Through the close interaction with Steve, the MUST team further realized that the success of scientific endeavors depends not only on advanced technology and abundant resources but also on sincere and unified collaboration between team members. The MUST team will learn from Steve and take every step thoughtfully, jointly leading the way to new heights in the MUST project. ![Steve guiding the work of the MUST team](https://must.astro.tsinghua.edu.cn/admin/uploads/20231115_143045_e95be30f93.jpg) ![Steve participating in a cycling activity with young members of the MUST team](https://must.astro.tsinghua.edu.cn/admin/uploads/20231115_143110_33231c0066.jpg) ![Steve and the MUST team participating in the Tsinghua DoA Fun Sports Meeting](https://must.astro.tsinghua.edu.cn/admin/uploads/20231115_143114_edbcfafadd.jpg)


The Precision Optoelectronic System R&D Center of MUltiplexed Survey Telescope (MUST), Tsinghua University Signs an Agreement to Settle in Xiake Bay Intelligent Park

On the morning of August 28, 2023, the signing ceremony for the entry projects of Xiake Bay Intelligent Park was held in Jiangyin. This event aims to build Xiake Bay Science City as a highland for technological innovation, promote high-quality development of the science and technology innovation industry, and inject vigorous energy into the modernization construction of “strong, prosperous, beautiful, and high-quality” new Jiangyin. ![Signing ceremony scene](https://must.astro.tsinghua.edu.cn/admin/uploads/1_0c04d4185c.jpg) Xu Feng, member of the Standing Committee of the Wuxi Municipal Party Committee and Secretary of the Jiangyin Municipal Party Committee, announced the opening of Xiake Bay Intelligent Park. Professor Gao Song, academician of the Chinese Academy of Sciences and President of Sun Yat-sen University, sent a video address. Mayor Bao Ming, Wang Qi, and other city leaders attended the event. Associate Professor Cai Zheng, Vice Director of the Department of Astronomy, Tsinghua University and MUST project manager, gave a speech, and Professor Huang Lei, Chief Engineer of MUST and long-term professor of the Department of Precision Instruments, Tsinghua University , was also present. ![Xu Feng, Secretary of the Jiangyin Municipal Party Committee, visiting the exhibition hall of Xiake Bay Intelligent Park](https://must.astro.tsinghua.edu.cn/admin/uploads/3_ca85c8aeec.jpg) The unveiling ceremony of Wuxi Applied Technology Research Institute Precision Optoelectronics R&D Center (MUST) of Tsinghua University will promote resource sharing and complementary advantages between Xiake Bay Science City and the MUST project, creating a new situation of win-win cooperation. ![the Unveiling ceremony](https://must.astro.tsinghua.edu.cn/admin/uploads/2_28cbc8af57.jpg) ![MUST project manager, Associate Professor Cai Zheng from the Department of Astronomy,Tsinghua University giving a speech](https://must.astro.tsinghua.edu.cn/admin/uploads/4_de131e7ae5.jpg) Source:“Jiangyin Release” official WeChat account


Representatives of École Polytechnique Fédérale de Lausanne (EPFL) Visit Tsinghua University for In-depth Communication with the MUST Team

From August 27 to 31, 2023, international collaborator and renowned cosmologist Professor Jean-Paul Kneib from École Polytechnique Fédérale de Lausanne (EPFL) visited Tsinghua University for in-depth discussions with the MUST scientific team. They worked together to outline and develop a work plan for the writing of the MUST Astrophysics Science White Paper. They also reported their findings and had exchanges with Vice President Wang Hongwei. Astrophysics science is an important component of the MUST project. During this visit, Professor Jean-Paul Kneib had in-depth discussions and exchanges with the MUST team on the research direction, key areas, and research plans of astrophysics science in the MUST project. He provided valuable opinions and suggestions for the writing of the MUST Astrophysics Science White Paper. Professor Jean-Paul Kneib is an outstanding representative in the field of international astrophysics. He has published papers in numerous top international academic journals and served as the chief scientist for several important international astrophysics projects. His visit not only provided valuable support and guidance for the research on astrophysics science in the MUST project but also played a positive role in promoting international cooperation and academic improvement at Tsinghua University. The writing of the MUST Astrophysics Science White Paper will provide important strategic references for the development of astrophysics science in the MUST project at Tsinghua University. It will also promote the integration and coordinated development of disciplines. In the future, Tsinghua University will continue to advance the research and development of astrophysics science in the MUST project and make positive contributions to the global astrophysics research. ![Jean-Paul Kneib communicating with the MUST team](https://must.astro.tsinghua.edu.cn/admin/uploads/3_20366364e2.jpg) ![Group photo with Vice President Wang Hongwei and the MUST team](https://must.astro.tsinghua.edu.cn/admin/uploads/1_4793622655.jpg) ![Visiting the mirror processing equipment at Nanjing Institute of Astronomical Optics and Technology, Chinese Academy of Sciences (NIAOT)](https://must.astro.tsinghua.edu.cn/admin/uploads/2_5de0867113.jpg)


Signing Ceremony of MUST Precision Optoelectronic System R&D Base Held in Jiangyin

On May 7, 2023, the precision optoelectronic system research and development base of MUST, Tsinghua University, signed a contract in Jiangyin. Guo Yong, Vice Secretary of the Party Committee of Tsinghua University, Xu Feng, member of the Standing Committee of the Wuxi Municipal Committee and Secretary of the Jiangyin Municipal Committee, Zheng Yongping, Dean of the Wuxi Applied Technology Research Institute of Tsinghua University, Niu Ben, Director of Domestic Cooperation Office of Tsinghua University, Cai Zheng, MUST Project Manager and Associate Chair of the Department of Astronomy, Tsinghua University, Huang Lei, MUST Project Chief Engineer, and Assistant Dean of the Department of Precision Instruments, and Jiangyin municipal leaders Wu Liping, Chen Hanjie, Cao Xinghua, and Qi Jun attended the signing ceremony. ![](https://must.astro.tsinghua.edu.cn/admin/uploads/_63c4195b11.png) Xu Feng expressed a warm welcome to Guo Yong and his delegation. He said that Tsinghua University is a world-renowned institution of higher education with a long history and profound background, and has made outstanding contributions to the country's construction and development, social civilization, and progress. Jiangyin is the flag of county-level economic development in the country, and is currently accelerating the construction of "Science and Technology Innovation Jiangyin". The project will be settled in the Xiake Bay Science City, which is a high-quality development, high-quality growth pole, vibrant innovation source, beautiful ecological area, and digital new height, which Jiangyin key builds. Xu Feng stated that the Jiangyin Municipal Party Committee and the government will fully support the project's landing, provide all convenience for the project construction, and sincerely invite Tsinghua University to establish more cooperation with Jiangyin, and create a new highland of school and land cooperation and a new model of political and research cooperation. Guo Yong stated that Jiangyin is blessed with both fine people and excellent geographical location, and the Jiangyin Municipal Party Committee and Government have left a deep impression on everyone by focusing on technological innovation to promote high-quality economic and social development. He pointed out that in 2021, Tsinghua University released the "Tsinghua University 2030 Innovation Action Plan", which focuses on optimizing disciplinary layout, strengthening disciplinary construction, intensifying basic research and tackling key core technologies, and prosperous development of humanities and social sciences. The Wide-Field Survey Telescope Project signed this time is an important part of it. Guo Yong hopes that both sides will continue to deepen and expand the breadth and depth of university-local cooperation, steadily promote the construction of large scientific facilities, and provide strategic support for serving the country's technological independence and self-improvement. ![](https://must.astro.tsinghua.edu.cn/admin/uploads/2_67e3d0409d.png) Deep space exploration is the "blue ocean" for breakthrough discoveries in the field of basic science. In the next decade, the development of deep space exploration will show further accelerated trends. However, in the extremely important fields of optics and infrared, the new generation of wide-field survey telescopes has yet to be completed internationally. In view of this, Tsinghua University has taken the lead in launching the important layout of constructing MUST, planning to build a large aperture, wide field of view, and high-efficiency spectral telescope. This facility belongs to the internationally leading large scientific installation, and is expected to achieve major fundamental and original breakthroughs in frontier directions such as dark energy evolution, nature of dark matter, and extrasolar planets, and obtain first-class international results. The MUST team will rely on the Wuxi Applied Technology Research Institute of Tsinghua University to establish the "Precision Optoelectronic R&D Center." They will focus on topics such as base construction, technology research and development, and outcome transfer and transformation, closely related to the large-scale optoelectronic equipment construction of MUST. They will accelerate the gathering of talents in the aerospace technology and high-end optical equipment manufacturing fields, and create a world-class scientific frontier R&D platform and application base to foster a good environment for scientific and technological innovation. Source: Wuxi Applied Technology Research Institute of Tsinghua University


The MUST scientific team published a paper on Science as the first author. Direct Imaging of Gas Recycling around a Massive Galaxy 11 Billion Years Ago

Galaxies are the birthplace of most stars and black holes. However, scientists are still debating, how galaxies accrete the fuel to sustain their growth and how they in turn pollute their environment with elements heavier than helium. The scientific team led by MUST project manager Cai Zheng at Tsinghua University has now directly observed the neighborhood of a massive galaxy in the early Universe. They find that the gas all around the galaxy is enriched with heavy elements, which means it has been polluted by the galaxy itself and by embedded satellite galaxies. Furthermore, this gas is spiraling onto the massive galaxy, fueling further star formation. ![](https://must.astro.tsinghua.edu.cn/admin/uploads/202305070957291_ad1a7fa44f.jpg) According to the first models of galaxy formation, gas fell isotropically onto dark matter halos, was shock-heated to very high temperatures (millions of degrees), and subsequently cooled to form stars in the emerging/growing central galaxy. However, it is now clear that this so-called ‘hot-mode’ accretion accounts for only a small fraction of the fuel powering the violent star formation in massive galaxies in the early universe. Instead, cosmological hydrodynamical simulations indicate that a ‘cold-mode’ accretion (thousands of degrees) onto galaxies occurs along filaments. This accretion process is more efficient in transporting gas down to the galaxy, providing a natural mechanism to sustain the observed large star-formation rates. In turn, stars pollute their surrounding environment with elements heavier than helium, globally referred to as “metals”. The most energetic phenomena (supernova explosions) are even able to generate galactic outflows, enriching the circumgalactic gas. Recent cosmological simulations indicate that this metal-enriched gas ejected by the galaxy could fall back, resulting in a further supply mechanism to sustain intense star-forming activity. Therefore, a massive galaxy will both recycle its metal-polluted gas and use pristine, inflowing gas, which should have a non-zero metal content. However, direct observational evidence for the presence of such recycled inflows had not been obtained so far. An international team of astronomers has therefore targeted a massive system in the early universe, to get a first glimpse on how such galaxies accrete their gas. The chosen system, MAMMOTH-1, can be observed at an epoch corresponding to 11 billion years ago. It is a galaxy group embedded in large-scale cold circumgalactic gas, which shines bright in Lyman-alpha emission from hydrogen. With data from the Keck Cosmic Web Imager (KCWI, Keck II telescope) and narrowband imaging from the Subaru telescope, the team detected circumgalactic line emission in hydrogen, helium, and carbon extending for 300 000 light years. An analysis of the line ratios allowed the team to obtain the gas properties throughout the halo. The results show that the circumgalactic gas has already been enriched to solar metallicity, which is quite surprising at this early cosmic epoch. Further, the KCWI data allowed the team to analyse the kinematics of the emitting gas in the observed region. A detailed comparison of the data with cosmological simulations and an analytical model can explain the observed velocity patterns, which are most likely due to recycled inflow gas. The kinematic model indicates that the gas accretion is occurring at a rate of about 700 solar masses per year, much more than the measured star-formation rate of the central galaxy (81 solar masses per year). The metal-enriched inflow could thus fully sustain the intense star formation in the massive galaxy. “Our observations give a first hint that recycled inflows might be an ubiquitous supply mechanism for massive star-forming galaxies in the early universe”, remarks Zheng Cai of Tsinghua University, the Principle Investigator of this study and corresponding author of this paper. In addition, the team also found that satellite galaxies in this galaxy group have the same motion as the circumgalactic gas, indicating that they are embedded in the inspiraling streams. Therefore, these satellite galaxies could interact with and pollute the circumgalactic gas. “This makes the galaxy-gas ecosystem even more complex, but also it makes more plausible that gas recycling is an important ingredient,” adds Shiwu Zhang of Tsinghua University and first-author of the study. In future, one could have a lot more sensitive observations of circumgalactic emission to give us more insights on the intricate ecosystem of galaxies. The upcoming exquisite datasets, such as from the MUSE/VLT, KCWI instruments, and JWST, allows astrophysicists to directly study the circumgalactic gas in detail and thus better understand the physical processes governing the gas cycle around galaxies. Source: Official website of Tsinghua University. official website of Department of Astronomy, Tsinghua University


Spring Team Building 2023 for Center for Astronomy Technology, Tsinghua University in Fenghuangling

In order to enrich the team's leisure activities, enhance communication and exchange among members, and establish a team atmosphere of mutual understanding and trust, the Center for Astronomy Technology, Tsinghua University launched a mountain climbing activity at Fenghuangling (Beijing) as the team building on April 27, 2023. And a total of 25 members from the MUST team participated in the activity. #### ![Group photo of the Center for Astronomy Technology, Tsinghua University](https://must.astro.tsinghua.edu.cn/admin/uploads/20230428134625_757ece5fce.jpg) #### ![Icebreaker for team members before the climb](https://must.astro.tsinghua.edu.cn/admin/uploads/202304281348584_e698674e68.jpg) ![group photo of climbing the top](https://must.astro.tsinghua.edu.cn/admin/uploads/20230428134645_fc7498d08b.jpg) During the mountain climbing, everyone had in-depth communications about work and life-related questions and experiences, achieving both physical fitness and the happiness and knowledge gained along the way. We encouraged and helped each other, and eventually reaching the summit. Collaborative teamwork helps us go further. The activity not only promoted the spirit of challenging oneself, forging ahead, and working together for the MUST team, but also advocated for a positive and healthy lifestyle, and “work healthily for 50 years for the country” with practical actions. The Center for Astronomy Technology, Tsinghua University will continue to strengthen team cohesion, improve team execution, and optimize team communication through various activities, striving to push the MUST project forward as soon as possible!


Tsinghua President Wang Xiqin led a delegation to visit Switzerland, and Cai Zheng, the project manager of MUST, attended the meeting

Wang Xiqin, president of Tsinghua University, took part in a series of bilateral and multilateral talks with his counterparts from worldwide universities, foreign officials, academics, businesspeople and representatives of international organizations during his attendance at the 2023 annual meeting of the World Economic Forum in Davos from January 16 to 18. At their meeting on January 17,Wang talked with Martin Vetterli, president of the École Polytechnique Fédérale de Lausanne (EPFL), and Jean-Paul Kneib, director of the EPFL's Astrophysics Laboratory, over the feasibility of the EPFL's participation in the building of the Multiplexed Survey Telescope (MUST). Wang said the EPFL is an important partner for Tsinghua University and called on the two universities to expand bilateral cooperation in talent cultivation, scientific research and people-to-people exchanges. Vetterli noted MUST has become a demonstration program for scientific research between China and Switzerland and the EPFL is willing to further deepen its cooperation with Tsinghua University in astronomy and basic physics. Cai Zheng, the Project Manager of MUST, Deputy Director of the Department of Astronomy, Tsinghua University, also attended the meeting. #### ![_Wang Xiqin meets with Martin Vetterli and Jean-Paul Kneib_](https://must.astro.tsinghua.edu.cn/admin/uploads/1_a809d248d9.png) ![](https://must.astro.tsinghua.edu.cn/admin/uploads/2_1c68e9b5ae.png) Source: Tsinghua University· News


Dadu Culture donates and supports the MUST project at Tsinghua University to explore the vast universe together.

Tsinghua News Network, June 7th: On June 4th, Dadu Cultural Communication Co., Ltd. (referred to as "Dadu Culture") donated to support the Multiplexed Survey Telescope (MUST) project at Tsinghua University. This donation will play a positive role in the development of the astronomy discipline, talent cultivation, and team building at Tsinghua University, promoting the construction of a world-class astronomical facility, providing strong support for further exploring the universe and advancing astronomical research. Dong Donghua, Chairman of Dadu Culture, and Qiu Yong, President of Tsinghua University, Wang Xiqin, Executive Vice President, and others attended the ceremony. The ceremony was presided over by Yang Bin, Vice President and Director of the Education Foundation. ![Dong Donghua makes a speech](http://localhost:1337/uploads/1_1_f6782ab841.png) Dong Donghua stated that Tsinghua University has achieved fruitful results by upholding the school motto of "Self-Discipline and Social Commitment(自强不息、厚德载物)" and adhering to a school culture of "actions speak louder than words" and an academic style of "diligence, rigor, seeking truth, and innovation". He hopes that this donation can play a positive role in promoting the construction of a world-class astronomical observation base and a Chinese university astronomy science education base. Dong Donghua also expressed that Dadu Culture will take this opportunity to establish a sound and effective long-term mechanism to continuously support the strategy of building a strong science and technology country. He also hopes to maintain comprehensive and long-term exchanges and cooperation with Tsinghua University in the future and wishes the university even greater success. ![Qiu Yong makes a speech](http://localhost:1337/uploads/1_2_7995724fc5.png) Qiu Yong first expressed his heartfelt thanks on behalf of Tsinghua University for Dadu Culture's donation and support. He said that on the eve of the 110th anniversary of the university, General Secretary Xi Jinping came to the school for an inspection and gave high recognition to Tsinghua's work, as well as expressing his earnest expectations for the university's long-term development. Qiu Yong emphasized that Tsinghua people should have a strong sense of national pride, not only upholding the school motto of "Self-Discipline and Social Commitment" and nurturing academic excellence, but also striving tirelessly for the great rejuvenation of the Chinese nation while embracing the spirit of "Tsinghua with global vision and local commitment". This is Tsinghua's mission and responsibility as a world-class university, and a conscious choice in the new journey towards national rejuvenation. Qiu Yong said that Tsinghua University is currently at an important stage of development, and this donation has three special meanings for the university's new development. Firstly, it supports basic research projects which can bring us profound reflections and promote original innovation capabilities, but its path is uncertain, and the results may take a long time to emerge, with practical value that cannot be manifested in the short term, therefore it requires more social resources investment. Secondly, it promotes the construction of talent team. The MUST project will continuously introduce outstanding talents with international competitiveness, form an academic team committed to deep research, and contribute to the project and the construction of Tsinghua's astronomical discipline. Thirdly, it helps Tsinghua's long-term development. According to the requirements of General Secretary Xi Jinping, the university is promoting strategic planning for future development, mainly including three aspects: first, formulate global strategy 2.0, seeking new global strategic development under new circumstances; secondly, improve the system of high-level talent training, provide personalized education according to individual talent characteristics; thirdly, launch the 2030 Tsinghua Innovation Action Plan, covering academic ecology construction, response to national major strategic demands, original innovation, and basic research, among which the MUST project has been included. Qiu Yong emphasized that we should, based on the university's resources, widely attract social forces to promote the high-quality development of projects such as MUST. The Department of Astronomy should take the lead in conducting high-level research, focus on doing truly valuable things, and cooperate closely with other departments and institutions such as the Academy of Science and Technology and domestic cooperative programs, so as not to let society down and make greater contributions to the country's innovation cause. ![Sign the donation agreement](http://localhost:1337/uploads/1_3_50bc48070b.png) ![Qiu Yong presented a donation commemorative plaque to Dong Donghua](http://localhost:1337/uploads/1_4_eb8650669d.png) At the ceremony, Dong Donghua and Yuan Wei, Secretary-General of Tsinghua University Education Foundation, signed the donation agreement. Qiu Yong presented a commemorative plaque to Dong Donghua for the donation. ![group photo](http://localhost:1337/uploads/1_5_08600df6bb.png) Representatives from Dadu Culture and heads of relevant schools and departments of Tsinghua University attended the ceremony. Aerospace science and technology is a strategic area in the new century research and development plan of Tsinghua University. The MUST project is considered to have the potential to make significant fundamental and original breakthroughs in many cutting-edge areas. Submitted by: The Education Foundation Editor: Chen Xiaoyan Reviewed by: Lv Ting.


Tsinghua University and the People's Government of Qinghai Province sign a cooperation agreement on the "Multiplexed Survey Telescope (MUST)" project.

On May 31st, the news website of Tsinghua University reported that on the afternoon of May 27th, the signing ceremony for the cooperation agreement between Tsinghua University and the Qinghai Provincial People's Government on the "Multiplexed Survey Telescope (MUST)" project was held at Tsinghua University. Wang Xiqin, member of the Standing Committee of the Qinghai Provincial Party Committee and Executive Vice President of Tsinghua University, among others, attended the signing ceremony. The ceremony was chaired by Fang Hongwei, Dean of the Office of Research Administration at Tsinghua University. ![Wang Xiqin giving a speech](http://localhost:1337/uploads/2_1_c6fd3219dc.png) On the ceremony, Wang Xiqin first welcomed the visit of the Qinghai Provincial Committee and thanked Qinghai Province for its trust and support to Tsinghua University in the "MUST" project. Wang Xiqin stated that astronomy and astrophysics are the disciplines with the greatest span of time and space in natural sciences. General Secretary Xi Jinping pointed out that astronomy is a cutting-edge science that nurtures major original discoveries and is a strategic high ground for promoting scientific and technological progress and innovation. Each significant discovery in astronomical observation continuously deepens human understanding of the mysteries of the universe. Space technology is a strategic layout field for the new century's scientific research and development plan of Tsinghua University, and the MUST project is an excellent choice with high consensus internationally and is expected to achieve significant breakthroughs in fundamental research. This time, Tsinghua University and Qinghai Province joined hands to build the MUST project in Saishenteng Mountain, Lenghu Town, Haixi Prefecture, Qinghai Province. Tsinghua University will coordinate relevant resources inside and outside the school and accelerate the progress of designing the project, constructing astronomical observation equipment, and operating and maintaining related research bases. Wang Xiqin hoped that the two sides will further deepen the cooperation between the province and the university, open up a new journey, achieve new results, and establish a new monument, contributing to the construction of a strong country in science and technology, education, and talents. ![Mao Shude introduced the MUST project and the preparatory progress](http://localhost:1337/uploads/2_2_821f0edc2e.png) Mao Shude, the director of the Department of Astronomy at Tsinghua University, then introduced the MUST project and the preparation work that had been done. He noted that China currently lags behind in large-aperture telescopes and general-purpose precision telescopes compared to international standards, and therefore it is urgent to develop them. The project aims to build a 6.5-meter wide-field (spectral) survey telescope at the Cold Lake observation base in Qinghai, and carry out all-round astronomical research based on it, striving for breakthroughs in several cutting-edge scientific areas. Tsinghua University and Qinghai Provincial Government have signed a cooperation agreement on the "Multiplexed Survey Telescope (MUST)" project. Mao Shude, director of the Department of Astronomy at Tsinghua University, introduced the preparation of the MUST project and its early stage. Mao Shude pointed out that China is currently seriously lagging behind the international level in both telescopes and terminal detection equipment, and therefore urgently needs to develop large-caliber survey telescopes and general-purpose precision measuring telescopes. Qinghai Province and Tsinghua University will spend about 7 years to build a 6.5-meter wide-field (spectral) survey telescope in Qinghai's Cold Lake, and based on this, carry out all-round astronomical research, striving to achieve major breakthroughs in several cutting-edge scientific fields. The Qinghai Provincial Department of Science and Technology introduced the drafting of the MUST project cooperation agreement and its main content. The relevant person in charge stated that in January 2021, Wang Xiqin, executive vice president of Tsinghua University, led a team to visit the Lenghu Astronomical Observation Base in Haixi Prefecture, Qinghai Province, and the Qinghai Provincial Government representatives hosted a special symposium on the MUST project. After that, the two sides actively carried out work, drafted the initial draft of the project cooperation agreement, and after several rounds of revision and soliciting opinions and suggestions from relevant experts, the signing text was finally formed today. It is believed that as an effective means to deepen the cooperation between the province and the university, the implementation of the MUST project will effectively leverage the advantages of Qinghai's Lenghu’s location and resources, promote the improvement of the discipline construction level of Tsinghua University, and achieve mutual benefit and win-win results. Subsequently, representatives of Tsinghua University and the Qinghai Provincial Government signed the "Qinghai Provincial People's Government and Tsinghua University 'Multiplexed Survey Telescope (MUST)' Project Cooperation Agreement". According to the agreement, both parties will cooperate in the construction of the MUST project in Saishiteng Mountain, Lenghu Town, Haixi Prefecture, Qinghai Province, based on the principle of complementary advantages, mutual benefit, mutual promotion, and common development, and jointly strive to build a world-class astronomical science facility. Officials from Haixi Prefecture, the Provincial Department of Science and Technology, the Lenghu Industrial Park, and representatives of Tsinghua University's Department of Astronomy, Research Institute, Domestic Cooperation Office, Laboratory Office, and Finance Office participated in the signing ceremony. Contributed by: Research Institute Edited by: Chen Xiaoyan, Li Huashan Reviewed by: Lv Ting, Zhou Xiangnan


Establishment of University-level Astronomy Technology Center

With the support of the Department of Astronomy of Tsinghua University, the Astronomy Technology Center was officially established on May 25, 2021, approved by the annual laboratory working committee of the school. The Astronomy Technology Center will become an important support platform for the Multiplexed Survey Telescope (MUST) project with gradually expanding scope of work. ![](http://localhost:1337/uploads/3_1_786ca4a92e.png) In the past decade, astronomical observations have won five Nobel Prizes in Physics, accounting for 50%, and this trend is expected to accelerate in the future. In recent years, the US, Europe, and Japan have deployed several large-scale photometric surveys, but these surveys urgently need matched spectroscopic surveys, and only spectroscopy can determine the fundamental properties of celestial bodies. In this regard, the Department of Astronomy proposed the construction of a wide-field spectroscopic survey telescope, the Multiplexed Survey Telescope (MUST). In September 2019, after deliberation by several academicians and experts organized by the Research Institute, it was believed that this telescope has the potential to achieve significant basic and original breakthroughs in frontiers such as dark energy and dark matter, gravitational wave cosmology, exoplanets, and galaxy formation. At the same time, MUST will also collaborate with China's manned space station telescope, which is planned to be launched in 2025, to provide critical spectral support for this major deep-space exploration project. MUST is internationally recognized as a cost-effective and excellent choice. Therefore, similar ideas have also been proposed internationally. However, Tsinghua University has taken the lead in this significant historical opportunity and is expected to take the lead in this world-leading international collaborative scientific platform. At the same time, this project may open up a new model of private capital assisting top basic scientific and engineering construction. In terms of science, the main function of MUST is to conduct sky surveys, discovering and verifying new laws of physics on larger and more extreme scales. In the first five years after its completion, MUST will implement a series of large-scale spectral survey projects, potentially opening up new fields in gravitational wave cosmology, cosmic inflation detection, dark energy nature, formation of the first generation galaxies and galaxy clusters, exoplanet detection, and confirmation of habitable Earths, galaxy structure and history, and other cutting-edge sciences. These are currently the "bottleneck" problems in astrophysics and even fundamental physics, and are also problems that the international astronomical community wants to solve first and may be solved in the next 10-20 years. In terms of technology, the main function of MUST will be a world-class optical detection platform, which will not only bring huge development to Chinese astronomy, but also drive rapid development in fields such as new micro-nano spectrometers, special optical materials, high-precision sensor manufacturing, large-scale precision machinery manufacturing, low-noise near-infrared detectors, and more from the perspective of cutting-edge science. These related technologies can be widely applied in areas such as national economy and people's livelihoods, deep space exploration for aerospace, and will play an important role in national economic construction and defense security. Based on the established Astronomy Technology Center platform, the scientific team and engineering team of the MUST project will be gradually formed. The management teams of the platform as a whole and each department will be organized by the project's chief scientist, fully utilizing the rich project management experience of Tsinghua University, effectively combining Tsinghua's strong engineering and technical capabilities, and strengthening collaboration with external partners to ensure the smooth construction, implementation, and operation of the Astronomy Technology Center.


MUST convenes the first scientific seminar

On May 8-9, 2021, the first scientific symposium of the MUltiplex Survey Telescope (MUST) was held at Tsinghua University. Experts and scholars from different fields in the astronomy community from China and abroad discussed the scientific highlights of MUST, as well as the technical requirements for the telescope. Professor Shude Mao, the head of the Department of Astronomy, introduced the overall background and progress of the MUST project. Professor Mao emphasized the importance of international communication during the design phase to avoid possible oversights and to strive for significant breakthroughs in several cutting-edge scientific directions. Associate Professor Zheng Cai, the chief scientist of the MUST project, stated that the symposium invited experts from various fields in astronomy from China and abroad. The goal is to cover more practical scientific demands from various fields in the design phase of MUST through the exchange of ideas, to meet the crucial breakthroughs in space observation and other fields in China. The scientific symposium covered research topics in various fields of astronomy. Experts and scholars from various locations discussed and shared their insights on planetary science, stellar science, nearby universe science, solar system, time domain, galaxy clusters, interstellar medium, active galactic nuclei, and other topics. They also exchanged ideas on significant astronomical breakthroughs that could be brought by ground-based optical observation in the next decade. Finally, the experts conducted a detailed analysis of the various important indicators of the MUST telescope, forming the theoretical basis for the next steps of the project. ![](http://localhost:1337/uploads/4_1_485c811b23.png)


Site selection for the Multiplex Survey Telescope project - Field inspection at Lenghu has concluded

From January 24th to 27th, 2021, Wang Xiqin, Executive Vice President of Tsinghua University, Mao Shude, Cai Zheng, Huang Lei from the Department of Astronomy and Precision Instruments, as well as representatives from the Research Institute, Laboratory Department, and Domestic Cooperation Office, went to the Saishitengshan area of Lenghu Town, Qinghai Province for on-site investigation. The members of the inspection team conducted a comprehensive investigation and research on the local geographical conditions, natural conditions, engineering conditions, transportation conditions, supporting conditions, progress of similar projects, and cooperation conditions, and had detailed discussions with the Qinghai Provincial Government on the cooperation status of the project. Site Overview: Lenghu Town: located in Saishiteng Mountain area, Mangya City, Haixi Prefecture, Qinghai Province, at the junction of Qinghai, Xinjiang, and Gansu provinces, 944 kilometers away from the provincial capital Xining, 430 kilometers from Delingha, and 230 kilometers from Dunhuang, with an average elevation of 2700 meters. Regional Plan: To build the largest astronomical observation base, astronomical technology industry base, and cultural tourism industry base in the northern hemisphere, with science and technology projects as the core. ![](http://localhost:1337/uploads/5_1_65981db9b2.png) Saishiteng Mountain, Lenghu Town: located in the northwestern part of Qinghai province, bordering Qinghai, Xinjiang and Gansu provinces. It is 944 km from the provincial capital of Xining, 430 km from Delingha, and 230 km from Dunhuang. The average altitude is 2700 meters. Coordinates: 93.895278E 38.606944N, Altitude: ranges from 4300 to 4500 meters. Conditions: After more than three years of on-site surveying, experimental observations, historical data analysis, it was found that the Saishiteng Mountain area in Lenghu Town has excellent sky conditions, high atmospheric transparency, and stable weather, making it a potential world-class astronomical observatory site. ![](http://localhost:1337/uploads/5_2_6033246a7c.png) The observation project at 3800 meters and 4200 meters has been underway for more than two years. The conditions here are not much different from those of top international observatories, slightly better than the Kitt Peak National Observatory in Arizona, USA, but slightly worse than the top observatories in Chile and Hawaii. Meteorological conditions: Temperature: The annual average temperature is 2-3℃, with large temperature differences between day and night. The extreme highest temperature is 34.2℃, and the extreme lowest temperature is -34.3℃. Wind: The prevailing winds are from the west or northwest, with an annual average of 6.8 m/s. The median wind speed at the 4200-meter peak is around 5-6m/s. Cloud: The annual cloud cover is about 30%. Precipitation: The annual precipitation is 17 millimeters. Light and atmosphere: Seeing: The median value is 0.77 arcseconds. Sky brightness: 22 mag/arcsec2. Aerosol optical depth: 0.21. Artificial lighting: 0. Engineering and geological conditions: There is a six-month construction period every year, and the foundation is made of granite rock. ![](http://localhost:1337/uploads/5_3_6cea00d45d.png) After this site survey, the following information was obtained: 1) the geographic conditions can basically meet the requirements for the construction, operation, and maintenance of scientific research facilities, as well as the basic living needs of scientific research and operation and maintenance personnel; 2) the preliminary assessment of the natural environment can basically meet the requirements for the construction of this project, and it is a top-quality observation site in China; 3) the local government actively promotes the development of the astronomical industry, and the policy formulation and regional planning meet the basic requirements for the construction and long-term operation of this project. The above provides a theoretical basis for further determining the site and carrying out the project. ![](http://localhost:1337/uploads/5_4_c4209af438.png)