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Caltech Authors (147.820 recursos)

Repository of works by Caltech published authors.

Group = Thirty Meter Telescope

Mostrando recursos 1 - 10 de 10

  1. New developments in instrumentation at the W. M. Keck Observatory

    Adkins, Sean M.; McLean, Ian S.; Fitzgerald, Michael P.; Larkin, James E.; Lewis, Hilton A.; Martin, Christopher; Mawet, Dimitri; Prochaska, J. X.; Wizinowich, Peter
    The W. M. Keck Observatory is committed to maintaining the scientific leadership of our observing community by matching our observers' skills and passions in their fields of astronomical science with a continuing dedication by the Observatory and its collaborators to the development of state of the art instrumentation and systems. Our science driven strategic plan guides these developments and informs our plans for the future. In this paper we describe the performance of recently completed new instruments, instrument upgrades, and infrastructure upgrade projects. We also describe the expected performance of projects currently in the development or construction phases. Projects recently...

  2. Thirty Meter Telescope science instruments: a status report

    Simard, Luc; Ellerbroek, Brent; Bhatia, Ravinder; Radovan, Matthew; Chisholm, Eric
    An overview of the current status of the science instruments for the Thirty Meter Telescope is presented. Three first-light instruments as well as a science calibration unit for AO-assisted instruments are under development. Developing instrument collaborations that can design and build these challenging instruments remains an area of intense activity. In addition to the instruments themselves, a preliminary design for a facility cryogenic cooling system based on gaseous helium turbine expanders has been completed. This system can deliver a total of 2.4 kilowatts of cooling power at 65K to the instruments with essentially no vibrations. Finally, the process for developing...

  3. The Infrared Imaging Spectrograph (IRIS) for TMT: multi-tiered wavefront measurements and novel mechanical design

    Dunn, Jennifer; Andersen, David; Chapin, Edward; Reshetov, Vlad; Wierzbicki, Ramunas; Herriot, Glen; Chalmer, Dean; Isbrucker, Victor; Larkin, James E.; Moore, Anna M.; Suzuki, Ryuji
    The InfraRed Imaging Spectrograph (IRIS) will be the first light adaptive optics instrument on the Thirty Meter Telescope (TMT). IRIS is being built by a collaboration between Caltech, the University of California, NAOJ and NRC Herzberg. In this paper we present novel aspects of the Support Structure, Rotator and On-Instrument Wavefront Sensor systems being developed at NRC Herzberg. IRIS is suspended from the bottom port of the Narrow Field Infrared Adaptive Optics System (NFIRAOS), and provides its own image de-rotation to compensate for sidereal rotation of the focal plane. This arrangement is a challenge because NFIRAOS is designed to host...

  4. Investigation of primary mirror segment's residual errors for the Thirty Meter Telescope

    Seo, Byoung-Joon; Nissly, Carl; Angeli, George; MacMynowski, Doug; Sigrist , Norbert; Troy, Mitchell; Williams, Eric
    The primary mirror segment aberrations after shape corrections with warping harness have been identified as the single largest error term in the Thirty Meter Telescope (TMT) image quality error budget. In order to better understand the likely errors and how they will impact the telescope performance we have performed detailed simulations. We first generated unwarped primary mirror segment surface shapes that met TMT specifications. Then we used the predicted warping harness influence functions and a Shack-Hartmann wavefront sensor model to determine estimates for the 492 corrected segment surfaces that make up the TMT primary mirror. Surface and control parameters, as...

  5. The Infrared Imaging Spectrograph (IRIS) for TMT: motion planning with collision avoidance for the on-instrument wavefront sensors

    Chapin, Edward L.; Dunn, Jennifer; Weiss, Jason; Gillies, Kim; Hayano, Yutaka; Johnson, Chris; Larkin, James; Moore, Anna; Riddle, Reed L.; Sohn, Ji Man; Smith, Roger; Suzuki, Ryuji; Walth, Gregory; Wright, Shelley
    The InfraRed Imaging Spectrograph (IRIS) will be a first-light client instrument for the Narrow Field Infrared Adaptive Optics System (NFIRAOS) on the Thirty Meter Telescope. IRIS includes three configurable tip/tilt (TT) or tip/tilt/focus (TTF) On-Instrument Wavefront Sensors (OIWFS). These sensors are positioned over natural guide star (NGS) asterisms using movable polar-coordinate pick-ofi arms (POA) that patrol an approximately 2-arcminute circular field-of-view (FOV). The POAs are capable of colliding with one another, so an algorithm for coordinated motion that avoids contact is required. We have adopted an approach in which arm motion is evaluated using the gradient descent of a scalar...

  6. The Infrared Imaging Spectrograph (IRIS) for TMT: Data Reduction System

    Walth, Gregory; Wright, Shelley A.; Weiss, Jason; Larkin, James E.; Moore, Anna M.; Chapin, Edward L.; Do, Tuan; Dunn, Jennifer; Ellerbroek, Brent; Gillies, Kim; Hayano, Yucata; Johnson, Chris; Marshall, Daniel; Riddle, Reed L.; Simard, Luc; Sohn, Ji Man; Suzuki, Ryuji; Wincensten, James
    IRIS (InfraRed Imaging Spectrograph) is the diffraction-limited first light instrument for the Thirty Meter Telescope (TMT) that consists of a near-infrared (0.84 to 2.4 μm) imager and integral field spectrograph (IFS). The IFS makes use of a lenslet array and slicer for spatial sampling, which will be able to operate in 100’s of different modes, including a combination of four plate scales from 4 milliarcseconds (mas) to 50 mas with a large range of filters and gratings. The imager will have a field of view of 34×34 arcsec^2 with a plate scale of 4 mas with many selectable filters. We...

  7. Thirty Meter Telescope (TMT) Narrow Field Infrared Adaptive Optics System (NFIRAOS) real-time controller preliminary architecture

    Kerley, Dan; Smith, Malcolm; Dunn, Jennifer; Herriot, Glen; Véran, Jean-Pierre; Boyer, Corinne; Ellerbroek, Brent; Gilles, Luc; Wang, Lianqi
    The Narrow Field Infrared Adaptive Optics System (NFIRAOS) is the first light Adaptive Optics (AO) system for the Thirty Meter Telescope (TMT). A critical component of NFIRAOS is the Real-Time Controller (RTC) subsystem which provides real-time wavefront correction by processing wavefront information to compute Deformable Mirror (DM) and Tip/Tilt Stage (TTS) commands. The National Research Council of Canada - Herzberg (NRC-H), in conjunction with TMT, has developed a preliminary design for the NFIRAOS RTC. The preliminary architecture for the RTC is comprised of several Linux-based servers. These servers are assigned various roles including: the High-Order Processing (HOP) servers, the Wavefront...

  8. A sodium laser guide star coupling efficiency measurement method

    Feng, Lu; Shen, Zhi-Xia; Xue, Suijian; Li, Yang-Peng; Jin, Kai; Otarola, Angel; Bo, Yong; Zuo, Jun-Wei; Bian, Qi; Wei, Kai; Hu, Jing-Yao
    A large telescope's adaptive optics (AO) system requires one or more bright artificial laser guide stars to improve its sky coverage. The recent advent of a high power sodium laser is perfect for such application. However, besides the output power, other parameters of the laser also have a significant impact on the brightness of the generated sodium laser guide star, mostly in non-linear relationships. When tuning and optimizing these parameters it is necessary to tune based on a laser guide star generation performance metric. Although return photon fluxis widely used, variability of the atmosphere and sodium layer makes it difficult...

  9. Control System Modeling for the Thirty Meter Telescope Primary Mirror

    MacMynowski, Douglas G.; Thompson, Peter M.; Shelton, J. Chris; Roberts, Lewis C., Jr.; Colavita, M. Mark; Sirota, Mark J.
    The Thirty Meter Telescope primary mirror is composed of 492 segments that are controlled to high precision in the presence of wind and vibration disturbances, despite the interaction with structural dynamics. The higher bandwidth and larger number of segments compared with the Keck telescopes requires greater attention to modeling to ensure success. We focus here on the development and validation of a suite of quasi-static and dynamic modeling tools required to support the design process, including robustness verification, performance estimation, and requirements flowdown. Models are used to predict the dynamic response due to wind and vibration disturbances, estimate achievable bandwidth...

  10. Robustness of the Thirty Meter Telescope Primary Mirror Control System

    MacMynowski, Douglas G.; Thompson, Peter M.; Shelton, Chris; Roberts, Lewis C.
    The primary mirror control system for the Thirty Meter Telescope (TMT) maintains the alignment of the 492 segments in the presence of both quasi-static (gravity and thermal) and dynamic disturbances due to unsteady wind loads. The latter results in a desired control bandwidth of 1Hz at high spatial frequencies. The achievable bandwidth is limited by robustness to (i) uncertain telescope structural dynamics (control-structure interaction) and (ii) small perturbations in the ill-conditioned influence matrix that relates segment edge sensor response to actuator commands. Both of these effects are considered herein using models of TMT. The former is explored through multivariable sensitivity...

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