Dr. Chihiro Tokoku Profile

Dr. Chihiro Tokoku

Research Engineer at National Astronomical Observatory of Japan

Publications (20)

Proceedings Article | 5 August 2024 Presentation + Paper

Presentation + Paper

Project overview and update on ULTIMATE-Subaru: the next-generation wide-field AO instrument for the Subaru telescope

Yosuke Minowa, Yusei Koyama, Masayuki Akiyama, Sadman Ali, Takamasa Bando, Joshua Carter, David Chandler, Chi-Yi Chou, Jesse Cranney, Celine D'Orgeville, Yutaka Hayano, Takashi Hattori, Roger Haynes, Dionne Haynes, Angela Hernandez Delgado, Nicholas Herrald, Masayuki Hirabayashi, Junichi Katakura, Masahiko Kimura, Tadayuki Kodama, Masahiro Konishi, Andrew Kruse, Noelia Martinez Rey, Kumiko Morihana, Masaki Morita, Kentaro Motohara, Yoshiyuki Obuchi, Hajime Ogane, Hirofumi Okita, Yoshito Ono, Shin Oya, Naohisa Sato, Yuhei Takagi, Hideki Takami, Ichi Tanaka, Yoko Tanaka, Koki Terao, Chihiro Tokoku, Fumihiro Uraguchi, Lu Wang, Shiang-Yu Wang, Kenshi Yanagisawa, Hiroshige Yoshida, Michitoshi Yoshida

Proceedings Volume 13096, 130961A (2024) https://doi.org/10.1117/12.3018698

KEYWORDS: Telescopes, Equipment, Wavefront sensors, Design, Adaptive optics, Near infrared, Imaging systems, Spectrographs, Prototyping, Sensors

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Proceedings Article | 18 July 2024 Presentation + Paper

Presentation + Paper

Development of novel high-efficiency and wideband medium-dispersion grisms for MOIRCS at Subaru Telescope

Ichi Tanaka, Noboru Ebizuka, Chihiro Tokoku, Takashi Hattori, Yusei Koyama, Kentaro Motohara, Michael Lemmen, Brian Elms, Koji Omata, Yosuke Minowa, Tadayuki Kodama

Proceedings Volume 13096, 130961N (2024) https://doi.org/10.1117/12.3019508

KEYWORDS: Prisms, Telescopes, Optical gratings, Fabrication, Antireflective coatings, Zinc selenide, Equipment, Diffraction gratings, Volume Bragg gratings

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Proceedings Article | 18 July 2024 Poster + Paper

Poster + Paper

Exo-NINJA at Subaru: fiber-fed spectro-imaging of exoplanets and circumstellar disks at R~4000

M. El Morsy, J. Lozi, O. Guyon, T. Currie, S. Vievard, J. Bryant, C. Tokoku, V. Deo, K. Ahn, F. Crous, A. Wang, Z. Sathi

Proceedings Volume 13096, 130966S (2024) https://doi.org/10.1117/12.3019179

KEYWORDS: Exoplanets, Spectrographs, Telescopes, Adaptive optics, Planets, Equipment, Single mode fibers, Wavefront sensors, Near infrared, Cameras

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Proceedings Article | 18 July 2024 Poster + Paper

Poster + Paper

Compensation of defective pixels by mechanical shift of an NIR array detector used in the NINJA echelle spectrograph

Kenshi Yanagisawa, Chihiro Tokoku, Kentaro Motohara, Shinobu Ozaki, Yoshito Ono, Yosuke Minowa, Takashi Moriya, Masami Ouchi, Nozomu Tominaga, Masayuki Tanaka, Yutaka Hayano, Yusei Koyama, Sadman Ali, Masaomi Tanaka, Masayuki Akiyama, Tohru Nagao, Yoshiki Matsuoka, Kosuke Kushibiki, Shogo Homan, Akino Yasuda, Tomoya Yukino, Riku Sato, Kensho Tanaka, Tomoyasu Yamamuro, Michitoshi Yoshida

Proceedings Volume 13096, 130966R (2024) https://doi.org/10.1117/12.3016873

KEYWORDS: Sensors, Spectrographs, Detector arrays, Simulations, Airglow, Adaptive optics, Telescopes, Near infrared, Motion detection, Calibration

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Proceedings Article | 29 August 2022 Poster + Paper

Poster + Paper

NINJA: an LTAO assisted optical and near-infrared spectrograph of Subaru Telescope

Chihiro Tokoku, Shinobu Ozaki, Takashi Moriya, Kenshi Yanagisawa, Kentaro Motohara, Masami Ouchi, Nozomu Tominaga, Masaomi Tanaka, Yoshito Ono, Yosuke Minowa, Yutaka Hayano, Yusei Koyama, Sadman Ali, Masayuki Tanaka, Masayuki Akiyama, Tohru Nagao, Yoshiki Matsuoka, Kosuke Kushibiki, Shogo Homan, Akino Yasuda, Michitoshi Yoshida

Proceedings Volume 12184, 121847R (2022) https://doi.org/10.1117/12.2627749

KEYWORDS: Spectrographs, Adaptive optics, Near infrared, Telescopes, Optical design, Astronomy, Tomography

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Proceedings Article | 15 December 2020 Presentation + Paper

Presentation + Paper

Mechanical cooler system for the infrared space mission SPICA

Keisuke Shinozaki, Yoichi Sato, Chihiro Tokoku, Masaru Saijo, Hiroyuki Ogawa, Takao Nakagawa, Kenichiro Sawada, Hiroyuki Sugita, Tadahito Mizutani, Hideo Matsuhara, Shoji Tsunematsu, Seiji Yoshida, Kenichi Kanao, Akinobu Okabayashi, Katsuhiro Narasaki, Hiroshi Shibai

Proceedings Volume 11443, 1144329 (2020) https://doi.org/10.1117/12.2562175

KEYWORDS: Space operations, Infrared imaging, Infrared radiation, Infrared telescopes, Cryogenics, Telescopes, Space telescopes, Astrophysics, Cooling systems, Failure analysis

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Proceedings Article | 13 December 2020 Presentation + Paper

Presentation + Paper

Cryogenic system of the infrared space mission SPICA

Takao Nakagawa, Ken Goto, Hidehiro Kaneda, Hideo Matsuhara, Jun Matsumoto, Tadahito Mizutani, Hiroyuki Ogawa, Masaru Saijo, Yoichi Sato, Kenichiro Sawada, Hiroshi Shibai, Keisuke Shinozaki, Hiroyuki Sugita, Shinsuke Takeuchi, Chihiro Tokoku, Thierry Tirolien, Hideki Uchida

Proceedings Volume 11443, 1144328 (2020) https://doi.org/10.1117/12.2561882

KEYWORDS: Cryogenics, Infrared radiation, Space operations, Infrared imaging, Cryocoolers, Telescopes, Cooling systems, Sensors

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Proceedings Article | 24 July 2018 Presentation + Paper

Presentation + Paper

Thermal and mechanical design of SPICA payload module

Hiroyuki Ogawa, Takao Nakagawa, Hideo Matsuhara, Chihiro Tokoku, Mitsunobu Kawada, Ken Goto, Shinsuke Takeuchi, Masaru Saijo, Keisuke Shinozaki, Yohichi Sato, Tadahito Mizutani, Hidehiro Kaneda, Hiroshi Shibai

Proceedings Volume 10698, 106980B (2018) https://doi.org/10.1117/12.2313308

KEYWORDS: Space telescopes, Telescopes, Mechanical engineering, Space operations, Cryogenics, Curium, Sensors, Cooling systems, Assembly equipment, Optical instrument design

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Proceedings Article | 21 September 2012 Paper

Paper

WISH for deep and wide NIR surveys

Toru Yamada, Ikuru Iwata, Makiko Ando, Mamoru Doi, Tomotsugu Goto, Yuji Ikeda, Masatoshi Imanishi, Akio Inoue, Satoru Iwamura, Nobuyuki Kawai, Masakazu Kobayashi, Tadayuki Kodama, Yutaka Komiyama, Mariko Kubo, Hideo Matsuhara, Ken Mawatari, Yoshiki Matsuoka, Tomoki Morokuma, Hidehiko Nakaya, Koji Ohta, Atsushi Okamoto, Shinki Oyabu, Yohichi Sato, Hiroyuki Sugita, Ryo Tsutsui, Chihiro Tokoku, Jun Toshikawa, Saku Tsuneta, Takehiko Wada, Kiyoto Yabe, Naoki Yasuda, Daisuke Yonetoku

Proceedings Volume 8442, 84421A (2012) https://doi.org/10.1117/12.925632

KEYWORDS: Galactic astronomy, Near infrared, Telescopes, Satellites, Ultraviolet radiation, Space telescopes, Mirrors, Stars, Astronomy, Optical filters

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Proceedings Article | 6 August 2010 Paper

Paper

WISH: wide-field imaging surveyor at high redshift

Toru Yamada, Mamoru Doi, Tomotsugu Goto, Yuji Ikeda, Masatoshi Imanishi, Akio Inoue, Satoru Iwamura, Ikuru Iwata, Nobuyuki Kawai, Masakazu A. R. Kobayashi, Tadayuki Kodama, Yutaka Komiyama, Hideo Matsuhara, Yoshiki Matsuoka, Tomoki Morokuma, Kouji Ohta, Shinki Oyabu, Yoichi Sato, Hiroyuki Sugita, Ryo Tsutsui, Chihiro Tokoku, Saku Tsuneta, Takehiko Wada, Kiyoto Yabe, Naoki Yasuda, Daisuke Yonetoku

Proceedings Volume 7731, 77311Q (2010) https://doi.org/10.1117/12.856561

KEYWORDS: Galactic astronomy, Space telescopes, Telescopes, Mirrors, Near infrared, Optical filters, Staring arrays, Ultraviolet radiation, James Webb Space Telescope, Sensors

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Proceedings Article | 28 July 2010 Paper

Paper

MOAO activities in Tohoku University

Masayuki Akiyama, Shin Oya, Kazuhiro Hane, Tong Wu, Chihiro Tohoku

Proceedings Volume 7736, 77362L (2010) https://doi.org/10.1117/12.857415

KEYWORDS: Adaptive optics, Telescopes, Microelectromechanical systems, Deformable mirrors, Wavefronts, Prototyping, Tomography, Digital signal processing, Diffraction, Amplifiers

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Proceedings Article | 23 July 2008 Paper

Paper

Automatic pre-cooling system for large infrared instruments

Koji Omata, Tetsuo Nishimura, Stephen Colley, David Cook, William Gorman, Barney Magrath, Lucio Ramos, Scot Kleinman, Chihiro Tokoku, Masahiro Konishi, Tomohiro Yoshikawa, Ichi Tanaka, Ryuji Suzuki

Proceedings Volume 7018, 70182E (2008) https://doi.org/10.1117/12.787173

KEYWORDS: Nitrogen, Liquids, Control systems, Sensors, Switches, Infrared radiation, Cryogenics, Collimators, Temperature metrology, Cooling systems

Read Abstract +

An infrared instrument used for observation has to keep the detector and optical components in a very cold environment during operation. However, because of maintenance, upgrades, and other routine work, there are situations that require the instrument to be warmed-up and then cooled-down again. At Subaru Observatory, our MOIRCS infrared instrument has required warm-up and cool-down several times a year for routine maintenance and filter replacement. The MOIRCS instrument has a large heat capacity and cool-down using only the closed cycle cooler is impractical due to the huge amount of time it would require. To address this problem Subaru engineers have created a mechanism to allow PRE-COOLING of the instrument via liquid nitrogen - allowing for a much faster pre-cool process. Even with liquid nitrogen, the pre-cool process requires 10 tanks and almost a week of continual monitoring in order to reach the desired target temperature. It is very difficult to work for such a long period of time at the oxygen starved summit of Mauna Kea (4205 meters),and issues of man-power and scheduling conflicts only add to the problems. To address these concerns Subaru developed an automated pre-cooling system which works continuously and remotely at the summit. The strategy was to have basic functionality for pre-cooling and user friendly interface. i.e. (1) Continuous cooling until the target temperature is reached by automated liquid nitrogen tank exchanges and precision temperature control by automated changes to the liquid nitrogen flow. (2) Remote monitoring and control of all parameter setting by Web browser as user interface (UI). The goal of the Subaru pre-cooling system was to make it both inexpensive and quick to implement by using existing technologies. The original goal (to cut down on labor and precision temperature control) has been attained through several pre-cooling and software/hardware modification cycles. We will report on the progress and status of our pre-cooling experiences in this presentation.

Proceedings Article | 28 June 2006 Paper

Paper

Infrared multi-object spectrograph of MOIRCS

Chihiro Tokoku, Ryuji Suzuki, Koji Omata, Masahiro Konishi, Tomohiro Yoshikawa, Masayuki Akiyama, Ichi Tanaka, Takashi Ichikawa, Tetsuo Nishimura

Proceedings Volume 6269, 62694N (2006) https://doi.org/10.1117/12.672418

KEYWORDS: Molybdenum, Stars, Telescopes, Sensors, Cryogenics, K band, Astronomical imaging, Spectroscopy, Spectrographs, Thermal effects

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Proceedings Article | 28 June 2006 Paper

Paper

MOIRCS: multi-object infrared camera and spectrograph for SUBARU

Takashi Ichikawa, Ryuji Suzuki, Chihiro Tokoku, Yuka Katsuno Uchimoto, Masahiro Konishi, Tomohiro Yoshikawa, Toru Yamada, Ichi Tanaka, Koji Omata, Tetsuo Nishimura

Proceedings Volume 6269, 626916 (2006) https://doi.org/10.1117/12.670078

KEYWORDS: Sensors, Telescopes, Digital signal processing, Optical benches, Imaging spectroscopy, Stars, Astronomical imaging, Molybdenum, Control systems, Spectroscopy

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Proceedings Article | 27 June 2006 Paper

Paper

Application of SQL database to the control system of MOIRCS

Tomohiro Yoshikawa, Koji Omata, Masahiro Konishi, Takashi Ichikawa, Ryuji Suzuki, Chihiro Tokoku, Yuka Katsuno Uchimoto, Tetsuo Nishimura

Proceedings Volume 6274, 62740Y (2006) https://doi.org/10.1117/12.670957

KEYWORDS: Databases, Control systems, Sensors, Data communications, Telescopes, Process control, Imaging spectroscopy, Telecommunications, Human-machine interfaces, Spectroscopes

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Proceedings Article | 7 March 2003 Paper

Paper

Tohoku University focal plane array controller (TOUFPAC)

Takashi Ichikawa, Daigo Matsumoto, Kenshi Yanagisawa, Yuka Katsuno, Ryuji Suzuki, Chihiro Tokoku, Ken'ichiro Asai, Tetsuo Nishimura

Proceedings Volume 4841, (2003) https://doi.org/10.1117/12.459864

KEYWORDS: Digital signal processing, Staring arrays, Clocks, Electronics, Control systems, Data conversion, Control systems design, Astronomy, Signal processing, Optical isolators

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Proceedings Article | 7 March 2003 Paper

Paper

Performance of HAWAII-2 FPAs for multi-object infrared camera and spectrograph

Yuka Katsuno, Takashi Ichikawa, Ken'ichiro Asai, Ryuji Suzuki, Chihiro Tokoku, Tetsuo Nishimura

Proceedings Volume 4841, (2003) https://doi.org/10.1117/12.461919

KEYWORDS: Astronomical imaging, Clocks, Spectrographs, Staring arrays, Control systems, Digital signal processing, Infrared cameras, Mercury cadmium telluride, Astronomy, Cameras

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Proceedings Article | 7 March 2003 Paper

Paper

MOIRCS: muti-object infrared camera and spectrograph for the Subaru Telescope

Chihiro Tokoku, Ryuji Suzuki, Takashi Ichikawa, Ken'ichiro Asai, Yuka Katsuno, Koji Omata, Toru Yamada, Atsuo Sasaki, Tetsuo Nishimura

Proceedings Volume 4841, (2003) https://doi.org/10.1117/12.461911

KEYWORDS: Imaging spectroscopy, Sensors, Astronomical imaging, Spectroscopy, Cryogenics, Telescopes, Control systems, Spectrographs, Astronomy, K band

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Proceedings Article | 7 March 2003 Paper

Paper

Optical design of MOIRCS

Ryuji Suzuki, Chihiro Tokoku, Takashi Ichikawa, Tetsuo Nishimura

Proceedings Volume 4841, (2003) https://doi.org/10.1117/12.461446

KEYWORDS: Chromatic aberrations, Optical design, Collimators, Telescopes, Mirrors, Cameras, Lens design, Tolerancing, Sensors, Silica

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Proceedings Article | 18 December 2002 Paper

Paper

Application of HAWAII-2 FPAs for an astronomical wide-field imager and multi-object spectrograph

Yuka Katsuno, Takashi Ichikawa, Daigo Matsumoto, Ken'ichiro Asai, Ryuji Suzuki, Chihiro Tokoku, Kenshi Yanagisawa, Tetsuo Nishimura

Proceedings Volume 4818, (2002) https://doi.org/10.1117/12.451042

KEYWORDS: Digital signal processing, Astronomy, Astronomical imaging, Control systems, Staring arrays, Electronics, Clocks, Spectrographs, Observatories, Mercury cadmium telluride

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Showing 5 of 20 publications

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