Kinematic optimization of upgrade to the Hobby-Eberly Telescope through novel use of commercially available three-dimensional CAD package

Wedeking, G.A.; Zierer, Joseph; Jackson, Jerry

doi:10.1117/12.857178

Cited by 12 publications

(6 citation statements)

References 22 publications

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“…It will be a third generation evolution of the trackers for HET and SALT, and is in essence a precision six-axis stage. The tracker is being developed by the Center for Electro-Mechanics (CEM) at the University of Texas at Austin [18][19][20][21][22][23][24][25][26][27] , with integration at the CEM facility scheduled for Fall 2010.…”

Section: Introduction: Het Wide Field Upgrade and Industrial Replicatmentioning

confidence: 99%

VIRUS: a massively replicated 33k fiber integral field spectrograph for the upgraded Hobby-Eberly Telescope

et al. 2010

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The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of a baseline build of 150 identical spectrographs (arrayed as 75 units, each with a pair of spectrographs) fed by 33,600 fibers, each 1.5 arcsec diameter, deployed over the 22 arcminute field of the upgraded 10 m Hobby-Eberly Telescope (HET). The goal is to deploy 96 units. VIRUS has a fixed bandpass of 350-550 nm and resolving power R~700. VIRUS is the first example of industrial-scale replication applied to optical astronomy and is capable of spectral surveys of large areas of sky. The method of industrial replication, in which a relatively simple, inexpensive, unit spectrograph is copied in large numbers, offers significant savings of engineering effort, cost, and schedule when compared to traditional instruments.The main motivator for VIRUS is to map the evolution of dark energy for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX ‡ ) using 0.8M Lyman-α emitting galaxies as tracers. The full VIRUS array is due to be deployed in late 2011 and will provide a powerful new facility instrument for the HET, well suited to the survey niche of the telescope. VIRUS and HET will open up wide field surveys of the emission-line universe for the first time. We present the design, cost, and current status of VIRUS as it enters production, and review performance results from the VIRUS prototype. We also present lessons learned from our experience designing for volume production and look forward to the application of the VIRUS concept on future extremely large telescopes (ELTs). * The Hobby -Eberly Telescope is operated by McDonald Observatory on behalf

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Section: Introduction: Het Wide Field Upgrade and Industrial Replicatmentioning

confidence: 99%

VIRUS: a massively replicated 33k fiber integral field spectrograph for the upgraded Hobby-Eberly Telescope

et al. 2010

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“…This upgrade project consists of three primary elements: also requires the design, fabrication, and deployment of a new prime focus instrument package (PFIP) and tracker [8][9][10][11][12][13][14] , as well as modification to the HET's azimuth bearings, to accommodate the additional weight being added to the telescope.…”

Section: Introductionmentioning

confidence: 99%

Performance verification testing for HET wide-field upgrade tracker in the laboratory

et al. 2010

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To enable the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), the McDonald Observatory (MDO) and the Center for Electro-mechanics (CEM) at the University of Texas at Austin are developing a new HET tracker in support of the Wide-Field Upgrade (WFU) and the Visible Integral-Field Replicable Unit Spectrograph (VIRUS). The precision tracker is required to maintain the position of a 3,100 kg payload within ten microns of its desired position relative to the telescope's primary mirror. The hardware system to accomplish this has ten precision controlled actuators. Prior to installation on the telescope, full performance verification is required of the completed tracker in CEM's lab, without a primary mirror or the telescope's final instrument package. This requires the development of a laboratory test stand capable of supporting the completed tracker over its full range of motion, as well as means of measurement and methodology that can verify the accuracy of the tracker motion over full travel (4m diameter circle, 400 mm deep, with 9 degrees of tip and tilt) at a cost and schedule in keeping with the HET WFU requirements. Several techniques have been evaluated to complete this series of tests including: photogrammetry, laser tracker, autocollimator, and a distance measuring interferometer, with the laser tracker ultimately being identified as the most viable method. The design of the proposed system and its implementation in the lab is presented along with the test processes, predicted accuracy, and the basis for using the chosen method * .

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“…This functionality proved useful in many areas, but one in particular played a key role in the hexapod design. The software user could enter a range of travel for all six hexapod actuators into the spreadsheet and execute a MS Excel macro, thus driving the hexapod actuators to the prescribed position, acquire a distance measurement in the CAD program, log the results in the spreadsheet, move to a new hexapod position and repeat the entire process, completely automated 12 . Once developed, the interference check process took less than 30 s to check each hexapod position.…”

Section: Figure 3 Hexapod Actuator Componentsmentioning

confidence: 99%

Design, testing, and installation of a high-precision hexapod for the Hobby-Eberly Telescope dark energy experiment (HETDEX)

et al. 2012

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Engineers from The University of Texas at Austin Center for Electromechanics and McDonald Observatory have designed, built, and laboratory tested a high payload capacity, precision hexapod for use on the Hobby-Eberly telescope as part of the HETDEX Wide Field Upgrade (WFU). The hexapod supports the 4200 kg payload which includes the wide field corrector, support structure, and other optical/electronic components. This paper provides a recap of the hexapod actuator mechanical and electrical design including a discussion on the methods used to help determine the actuator travel to prevent the hexapod payload from hitting any adjacent, stationary hardware. The paper describes in detail the tooling and methods used to assemble the full hexapod, including many of the structures and components which are supported on the upper hexapod frame. Additionally, details are provided on the installation of the hexapod onto the new tracker bridge, including design decisions that were made to accommodate the lift capacity of the HobbyEberly Telescope dome crane. Laboratory testing results will be presented verifying that the performance goals for the hexapod, including positioning, actuator travel, and speeds have all been achieved. This paper may be of interest to mechanical and electrical engineers responsible for the design and operations of precision hardware on large, ground based telescopes. In summary, the hexapod development cycle from the initial hexapod actuator performance requirements and design, to the deployment and testing on the newly designed HET tracker system is all discussed, including lessons learned through the process.

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Kinematic optimization of upgrade to the Hobby-Eberly Telescope through novel use of commercially available three-dimensional CAD package

Cited by 12 publications

References 22 publications

VIRUS: a massively replicated 33k fiber integral field spectrograph for the upgraded Hobby-Eberly Telescope

VIRUS: a massively replicated 33k fiber integral field spectrograph for the upgraded Hobby-Eberly Telescope

Performance verification testing for HET wide-field upgrade tracker in the laboratory

Design, testing, and installation of a high-precision hexapod for the Hobby-Eberly Telescope dark energy experiment (HETDEX)

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