登录
 机构网站
  1. 首页
  2. 情报产品
  3. 快讯详情

《美国三十米望远镜宽视场光谱仪（WFOS）评估》

  • 来源专题：天文仪器与技术信息
  • 编译者： zwg@niaot.ac.cn
  • 发布时间：2017-05-11

  • The TMT Wide-Field Optical Spectrometer (WFOS) team held a key review at the TMT Project Office on May 2-3, 2017. WFOS is planned to be one of TMT’s first-light instruments, together with the Infrared Imaging Spectrograph (IRIS). An external committee reviewed the work performed during the Opto-Mechanical Design and Requirements (OMDR) phase, which focused on the end-to-end optical design configuration, key mechanical design elements and the designs of the two cameras.

    The international team updated the review committee on the latest WFOS science priorities. WFOS’s design will offer extraordinary new capabilities to study the early, distant universe, including the first stars and galaxies. The spectrometer will also allow new understanding of the composition of the intergalactic medium that fills space, revealing how heavy elements were spread by early star formation.

    Technical advances and performance analyses were presented and discussed, including, for example, ways to reduce the distortion through the optical chain.

    The technical review was followed by a one-day planning session to explore how to bridge the OMDR phase and the follow-up phase. Alternative architectures for the WFOS were discussed and priorities generated on different tasks to explore the viability of those alternatives. The team members volunteered to take up tasks that were closest to their own areas of technical expertise, and generated a roadmap toward down selecting one design. The goal is to move into a formal conceptual design phase as soon as possible.

    The TMT partnership promotes strong international participation in the development of its science instrument suite, and WFOS represents a collaboration among Caltech, the Indian Institute of Astrophysics (IIA), the Nanjing Institute of Astronomical Optics and Technology (NIAOT), the National Astronomical Observatory of Japan (NAOJ), the University of California Observatories (UCO) and the Lawrence Livermore National Laboratory (LLNL).

    The Principal Investigator is Kevin Bundy (UCO), the Project Manager is Maureen Savage (UCO), the Lead Engineer is Matthew Radovan (UCO) and the WFOS Project Scientist is Charles Steidel (Caltech).

    Presentations and discussions on TMT’s WFOS instrument at the TMT Project Office in Pasadena

  • 原文来源：http://www.tmt.org/news-center/tmt-wide-field-optical-spectrometer-wfos-review
188浏览量
原文链接
相关报告

  • 《美国三十米望远镜TMT宽视场光谱仪概念设计获进展》
    • 来源专题：天文仪器与技术信息
    • 编译者：zwg@niaot.ac.cn
    • 发布时间：2020-11-02
    • One of TMT’s three “Early Light” instruments, the Wide-Field Optical Spectrometer (WFOS), recently underwent an interim Conceptual Design Review via Zoom. The review’s purpose was to assess the instrument’s progress to date and to provide guidance on potential work needed to successfully complete the technical and scientific aspects to bring the overall design to a full Conceptual Design level. The review identified additional science cases, recommended additional functional requirements and provided an initial assessment of the new opto-mechanical concept. The scope for the WFOS interim review included assessing the following: Breadth of the proposed science cases Flexibility, efficiency and risks within the operational concepts Consideration given to trade-studies, manufacturability, performance and risks of the optical design Consideration given to trade-studies, functionality, complexity, performance and risks of the mechanical design. WFOS is envisioned as a workhorse instrument and is designed to provide highly flexible scientific capabilities while striving to maintain an overall low risk design. In 2018, WFOS underwent an extensive trade study between two fundamentally different architectures. These two concepts included exploring a bank of small, fiber fed, spectrographs and the current large ‘monolithic optic’ design. Since this down-select the WFOS team have diligently worked to produce an interim design concept that addresses and retires earlier identified risks for the chosen monolithic concept. The key design adaptations are summarized as follows: Exploiting advances in manufacturing techniques for large optics has enabled the WFOS field of view to be centered on the telescope optical axis; as opposed to previous designs where the field was offset by 4.8 arcminutes. This enables the instrument to be physically smaller. Flowing from the first bullet, the more compact on-axis design allowed the team to repackage the instrument so the incoming beam is now deflected downward within the instrument and hence is parallel to gravity. This allows WFOS to rotate around its vertical axis during operation, producing a gravity invariant design that greatly reduces concerns about instrument flexure and likely removes the need for a complicated flexure control system. To maintain a simple and cost-effective design capable of achieving several spectral resolution modes as well as an imaging mode, the WFOS cameras articulate. The cameras’ articulation is also gravity invariant. As described by one of the WFOS review panel members, the “WFOS technical team deserves a huge heartfelt congratulations for improving the design of WFOS on pretty much every axis. The descopes made from the WFOS-2013 design are smart, the instrument looks way more buildable, and the predicted performance is outstanding and realistic. I also want to commend the team for using a high-tech solution (the freeform collimator) to cleverly rebalance the risk! WFOS will be an instrument that will cause, what the young people call, FOMO (fear of missing out).” More about the current design WFOS will support three main modes of operation: direct imaging, long single slit spectroscopy, and multi-slit spectroscopy. The workhorse spectrograph will support several spectral resolutions including R = 1,500 and R = 3,500; with the R = 1,500 mode capturing the entire instrument bandpass in a single exposure. The current design also satisfies a goal of providing a spectral resolution mode of 5,000. The described modes use 0.75” slit widths; however, the instrument optics are designed to preserve image quality for narrower slits down to 0.25”, enabling higher spectral resolutions (up to 15,000) at the expense of throughput. Science programs using narrow slits will benefit most from the implementation of ground layer adaptive optics correction as part of a potential future upgrade to the Observatory. WFOS is also capable of directly imaging its entire science field of view providing the Observatory with a wide-field imaging mode at early light. WFOS will be the only TMT instrument capable of obtaining spectra at optical wavelengths (WFOS’s bandpass is 0.31−1.0 μm) for at least the first several years of TMT operations. For this reason, an important consideration for the design has been versatility, to ensure WFOS will be capable of addressing a very wide range of science. WFOS core science themes include the study of: Tomography of the high-redshift galaxies. How are proto-galaxies shaped by their gaseous environment and how do they affect that environment? The origin and properties of stellar populations in nearby galaxies. The key mechanisms that initiate the final stages of galaxy evolution. The nature of transient sources. WFOS will achieve the most sensitive optical spectroscopy ever attempted. It is expected that WFOS will often be used as the highest sensitivity spectroscopic capability, for the purpose of either initial identification or high-quality follow-up of new discoveries. WFOS will promote advances in many different topics and will serve teams of researchers spanning a broad range of scientific interests. Its most exciting discoveries are likely impossible to predict, but among its many areas of investigations, WFOS will study the distribution and nature of dark matter in the universe, as well as the composition of high-redshift galaxies, the physics of supernovae and gamma-ray burst events. The WFOS collaborating institutions are: The California Institute of Technology (CIT); The Indian Institute of Astrophysics (IIA) on behalf of the India TMT Co-ordination Center (ITCC); The Nanjing Institute of Astronomical Optics and Technology (NIAOT) on behalf of the National Astronomical Observatory of China (NAOC); The National Astronomical Observatory of Japan (NAOJ) on behalf of the National institute of Natural Science (NINS) and The University of California Observatories (UCO).  
    144浏览量
    原文链接

  • 《美国三十米望远镜（TMT）宽视场光谱仪中国合作伙伴会议》
    • 来源专题：天文仪器与技术信息
    • 编译者：zwg@niaot.ac.cn
    • 发布时间：2017-10-31
    • Representatives from the Thirty Meter Telescope’s (TMT’s) Wide-Field Optical Spectrograph (WFOS) team and TMT’s China partners gathered recently in China to discuss potential collaboration during the next stage of the conceptual design of WFOS. WFOS is planned to be one of TMT’s first-light instruments. It will offer extraordinary new capabilities to study the early, distant universe, including the first stars and galaxies, and the intergalactic medium. WFOS is now in its conceptual design phase, studying two different instrument designs: a slicer-based concept, and a fiber-based concept. The final decision will be made in March 2018. The next step will then include optimizing and prototyping the opto-mechanical design, fiber or slicer concepts, cameras, dispersive architecture, large refractive gratings, dichroics, robotics systems, and details of detector design. This will be followed by a two-year preliminary design phase, then final design, fabrication and integration and test phases, prior to fielding and commissioning on the telescope. Dr. Fengchuan Liu, the Deputy Project Manager of TMT, updated the current status of TMT to all attendees remotely. WFOS Instrument Project Manager Maureen Savage (UCO), Lead Engineer Matthew Radovan (UCO) and Dr. Zheng Cai (UCO) introduced the program, the technical opportunities and the science goals of WFOS, respectively. Representatives from several Institutes of Chinese Academy of Sciences and universities introduced their interests and their corresponding abilities, including National Astronomical Observatories of China (NAOC) and its affiliate, Nanjing Institute of Astronomical Optics & Technology (NIAOT); Shanghai Astronomical Observatory (SHAO); Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP); Shanghai Institute of Optics and Fine Mechanics (SIOM), University of Science and Technology of China (USTC); Shanghai Jiao Tong University (STJU); Huazhong University of Science and Technology (HUST); Beijing Institute of Technology (BIT). The TMT WFOS delegation also visited SHAO, SIOM, NIAOT, USTC and Tsinghua University, and held face-to-face discussions with each team.
    72浏览量
    原文链接