&lt;title&gt;Edge Sensors For A Segmented Mirror&lt;/title&gt;

Mast, Terry S.; Gabor, George; Nelson, Jerry

doi:10.1117/12.937989

“…Many engineering efforts and practical mathematics were behind the success of the segmented mirror technology. The development of edge sensors, 18) careful mathematical analyses, 14) and polishing the aspheric surface by bending mirrors during polishing 19) were all indispensable. This technology became a legacy for next-generation telescopes: Spanish 10.4 m telescope (GTC, 2009), 20) Thirty Meter Telescope (TMT), 21) and European Extremely Large Telescope (E-ELT).…”

Section: Japan National Large Telescope Working Groupmentioning

confidence: 99%

Subaru Telescope —History, active/adaptive optics, instruments, and scientific achievements—

Iye

¹

2021

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

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The Subaru Telescope a) is an 8.2 m optical/infrared telescope constructed during 1991-1999 and has been operational since 2000 on the summit area of Maunakea, Hawaii, by the National Astronomical Observatory of Japan (NAOJ). This paper reviews the history, key engineering issues, and selected scientific achievements of the Subaru Telescope. The active optics for a thin primary mirror was the design backbone of the telescope to deliver a high-imaging performance. Adaptive optics with a laser-facility to generate an artificial guide-star improved the telescope vision to its diffraction limit by cancelling any atmospheric turbulence effect in real time. Various observational instruments, especially the wide-field camera, have enabled unique observational studies. Selected scientific topics include studies on cosmic reionization, weak/strong gravitational lensing, cosmological parameters, primordial black holes, the dynamical/chemical evolution/interactions of galaxies, neutron star mergers, supernovae, exoplanets, proto-planetary disks, and outliers of the solar system. The last described are operational statistics, plans and a note concerning the culture-and-science issues in Hawaii.

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“…Many engineering efforts and practical mathematics were behind the success of the segmented mirror technology. The development of edge sensors (18), careful mathematical analyses (14), and polishing the aspheric surface by bending mirrors (19) were all indispensable. This technology became a legacy for next-generation telescopes: Spanish 10.4 m telescope (GTC, 2009) (20), Thirty Meter Telescope (TMT) (21), and European Extremely Large Telescope (E-ELT) (22).…”

Section: Japan National Large Telescope Working Groupmentioning

confidence: 99%

Subaru Telescope -- History, Active/Adaptive Optics, Instruments, and Scientific Achievements

Iye

2021

Preprint

0

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The Subaru Telescope a) is an 8.2 m optical/infrared telescope constructed during 1991-1999 and has been operational since 2000 on the summit area of Maunakea, Hawaii, by the National Astronomical Observatory of Japan (NAOJ). This paper reviews the history, key engineering issues, and selected scientific achievements of the Subaru Telescope. The active optics for a thin primary mirror was the design backbone of the telescope to deliver a high-imaging performance. Adaptive optics with a laser-facility to generate an artificial guide-star improved the telescope vision to its diffraction limit by cancelling any atmospheric turbulence effect in real time. Various observational instruments, especially the wide-field camera, have enabled unique observational studies. Selected scientific topics include studies on cosmic reionization, weak/strong gravitational lensing, cosmological parameters, primordial black holes, the dynamical/chemical evolution/interactions of galaxies, neutron star mergers, supernovae, exoplanets, proto-planetary disks, and outliers of the solar system. The last described are operational statistics, plans and a note concerning the culture-and-science issues in Hawaii.

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“…Typically two edge sensors are required per edge to provide the relative height and twist of adjacent segments. On the Keck telescope, the edge sensors have an operating range of 20 9m, a bandwidth of 100 Hz and a noise level of about 0.5 nm (Mast et al, 1983). Edge sensors are best at defining the positions of segments with respect to their neighbors, but not over the scale of the overall mirror because of error propagation.…”

Section: Edge Sensor and Measurement Noisementioning

confidence: 99%

H₂ Control of Large Segmented Telescopes

Jiang

¹

,

Voulgaris

²

,

Holloway

³

et al. 2009

Journal of Vibration and Control

9

0

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In this paper we conduct a preliminary study of control of the primary mirror of a large segmented telescope, i.e. aligning the segments to form a paraboloid. This work is motivated by the need of astronomers to study faint objects and to reach the highest possible angular resolution. First, we present background information about large segmented telescopes and our collaborative research program on large telescopes. Second, we formulate a model of the primary mirror system in state space. Third, we design a centralized controller using H2 methods for a seven-segment system which establishes the best possible performance characteristics for the laboratory-type of unit that we plan to build. Simulation results are displayed. Finally, we apply spatially-invariant distributed control techniques to an infinite segmented system that approximates a large mirror. Through the H2 norm, we calculate upper bounds for the relative displacements between adjacent segments with either a spatially-invariant infinite controller or a truncated local controller. Simulation results are also presented with a truncated local controller applied to a 19-segment system. In all cases, the results indicate that the required mirror-to-mirror surface position accuracy of 10-8 m can be achieved.

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<title>Edge Sensors For A Segmented Mirror</title>

Cited by 11 publications

References 6 publications

Subaru Telescope —History, active/adaptive optics, instruments, and scientific achievements—

Subaru Telescope —History, active/adaptive optics, instruments, and scientific achievements—

Subaru Telescope -- History, Active/Adaptive Optics, Instruments, and Scientific Achievements

H₂ Control of Large Segmented Telescopes

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<title>Edge Sensors For A Segmented Mirror</title>

Cited by 11 publications

References 6 publications

Subaru Telescope —History, active/adaptive optics, instruments, and scientific achievements—

Subaru Telescope —History, active/adaptive optics, instruments, and scientific achievements—

Subaru Telescope -- History, Active/Adaptive Optics, Instruments, and Scientific Achievements

H2 Control of Large Segmented Telescopes

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H₂ Control of Large Segmented Telescopes