Dr. Saku Tsuneta Profile

Dr. Saku Tsuneta

at National Astronomical Observatory of Japan

SPIE Involvement:

Author

Publications (22)

Proceedings Article | 21 November 2017 Open Access

Instrument design and on-orbit performance of the solar optical telescope aboard hinode (Solar-B)

Yoshinori Suematsu, Kiyoshi Ichimoto, Yukio Katsukawa, Saku Tsuneta, Toshifumi Shimizu

Proceedings Volume 10566, 105662Z (2017) https://doi.org/10.1117/12.2308204

KEYWORDS: Mirrors, Space telescopes, Telescopes, Secondary tip-tilt mirrors, Optical instrument design, Wavefronts, Optical telescopes, Polarization, Space operations, Spatial resolution

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Proceedings Article | 17 November 2017 Open Access

Development of compact integral field unit for spaceborne solar spectro-polarimeter

Y. Suematsu, M. Koyama, T. Sukegawa, Y. Enokida, K. Saito, Y. Okura, T. Nakayasu, S. Ozaki, S. Tsuneta

Proceedings Volume 10563, 105634M (2017) https://doi.org/10.1117/12.2304257

KEYWORDS: Mirrors, Micromirrors, Spectrographs, Optics manufacturing, Surface roughness, Iterated function systems, Metals, Cutting equipment, Astronomical imaging, Image quality

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A 1.5-m class aperture Solar Ultra-violet Visible and IR telescope (SUVIT) and its instruments for the Japanese next space solar mission SOLAR-C [1] are under study to obtain critical physical parameters in the lower solar atmosphere. For the precise magnetic field measurements covering field-of-view of 3 arcmin x3 acmin, a full stokes polarimetry at three magnetic sensitive lines in wavelength range of 525 nm to 1083 nm with a four-slit spectrograph of two dinesional image scanning mechanism is proposed: one is a true slit and the other three are pseudo-slits from integral field unit (IFU). To suit this configuration, besides a fiber bundle IFU, a compact mirror slicer IFU is designed and being developed.

Integral field spectroscopy (IFS), which is realized with IFU, is a two dimensional spectroscopy, providing spectra simultaneously for each spatial direction of an extended two-dimensional field. The scientific advantages of the IFS for studies of localized and transient solar surface phenomena are obvious. There are in general three methods [2][3] to realize the IFS depending on image slicing devices such as a micro-lenslet array, an optical fiber bundle and a narrow rectangular image slicer array.

So far, there exist many applications of the IFS for ground-based astronomical observations [4]. Regarding solar instrumentations, the IFS of micro-lenslet array was done by Suematsu et al. [5], the IFS of densely packed rectangular fiber bundle with thin clads was realized [6] and being developed for 4-m aperture solar telescope DKIST by Lin [7] and being considered for space solar telescope SOLAR-C by Katsukawa et al. [8], and the IFS with mirror slicer array was presented by Ren et al. [9] and under study for up-coming large-aperture solar telescope in Europe by Calcines et al. [10]

From the view point of a high efficiency spectroscopy, a wide wavelength coverage, a precision spectropolarimetry and space application, the image slicer consisting of all reflective optics is the best option among the three. However, the image slicers are presently limited either by their risk in the case of classical glass polishing techniques (see Vivès et al. [11] for recent development) or by their optical performances when constituted by metallic mirrors. For space instruments, small sized units are much advantageous and demands that width of each slicer mirror is as narrow as an optimal slit width (< 100 micron) of spectrograph which is usually hard to manufacture with glass polishing techniques. On the other hand, Canon is developing a novel technique for such as high performance gratings which can be applicable for manufacturing high optical performance metallic mirrors of small dimensions.

For the space-borne spectrograph of SUVIT to be aboard SOLAR-C, we designed the IFS made of a micro image slicer of 45 arrayed 30-micron-thick metal mirrors and a pseudo-pupil metal mirror array re-formatting three pseudo-slits; the design is feasible for optical configuration sharing a spectrograph with a conventional real slit. According to the optical deign, Canon manufactured a prototype IFU for evaluation, demonstrating high performances of micro image slicer and pupil mirrors; enough small micro roughness for visible light spectrographs, sharp edges for efficient image slices, surface figure for high image quality, etc. In the following, we describe the optical design of IFU feasible for space-borne spectrograph, manufacturing method to attain high optical performance of metal mirrors developed by Canon, and resulted performance of prototype IFU in detail.

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Proceedings Article | 28 July 2014 Paper

Development of micro image slicer of integral field unit for spaceborne solar spectrograph

Y. Suematsu, T. Sukegawa, Y. Okura, T. Nakayasu, Y. Enokida, M. Koyama, K. Saito, S. Ozaki, S. Tsuneta

Proceedings Volume 9151, 91511S (2014) https://doi.org/10.1117/12.2054569

KEYWORDS: Mirrors, Spectrographs, Micromirrors, Optics manufacturing, Surface roughness, Image quality, Optical design, Prototyping, Iterated function systems, Metals

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Proceedings Article | 21 September 2012 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 | 17 September 2012 Paper

The x-ray/EUV telescope for the Solar-C mission: science and development activities

Taro Sakao, Noriyuki Narukage, Shinsuke Imada, Yoshinori Suematsu, Masumi Shimojo, Saku Tsuneta, Edward DeLuca, Kyoko Watanabe, Shin-nosuke Ishikawa

Proceedings Volume 8443, 84430A (2012) https://doi.org/10.1117/12.926850

KEYWORDS: X-ray telescopes, X-rays, Mirrors, Coronagraphy, Space telescopes, Magnetism, Plasma, Telescopes, Spatial resolution, X-ray imaging

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Proceedings Article | 17 September 2012 Paper

Chromospheric Lyman-alpha spectro-polarimeter (CLASP)

Ryouhei Kano, Takamasa Bando, Noriyuki Narukage, Ryoko Ishikawa, Saku Tsuneta, Yukio Katsukawa, Masahito Kubo, Shin-nosuke Ishikawa, Hirohisa Hara, Toshifumi Shimizu, Yoshinori Suematsu, Kiyoshi Ichimoto, Taro Sakao, Motoshi Goto, Yoshiaki Kato, Shinsuke Imada, Ken Kobayashi, Todd Holloway, Amy Winebarger, Jonathan Cirtain, Bart De Pontieu, Roberto Casini, Javier Trujillo Bueno, Jiří Štĕpán, Rafael Manso Sainz, Luca Belluzzi, Andres Asensio Ramos, Frédéric Auchère, Mats Carlsson

Proceedings Volume 8443, 84434F (2012) https://doi.org/10.1117/12.925991

KEYWORDS: Polarization, Magnetism, Mirrors, Coating, Wave plates, Spectrographs, Scattering, Visible radiation, Cameras, Solar processes

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Proceedings Article | 10 November 2011 Paper

Modeling and verification of the diffraction-limited visible light telescope aboard the solar observing satellite HINODE

Y. Katsukawa, Y. Suematsu, S. Tsuneta, K. Ichimoto, T. Shimizu

Proceedings Volume 8336, 83360F (2011) https://doi.org/10.1117/12.918244

KEYWORDS: Telescopes, Space telescopes, Space operations, Thermal modeling, Mirrors, Performance modeling, Thermography, Optical telescopes, Visible radiation, Temperature metrology

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Proceedings Article | 7 October 2011 Paper

Ly-alpha polarimeter design for CLASP rocket experiment

H. Watanabe, N. Narukage, M. Kubo, R. Ishikawa, T. Bando, R. Kano, S. Tsuneta, K. Kobayashi, K. Ichimoto, J. Trujillo-Bueno

Proceedings Volume 8148, 81480T (2011) https://doi.org/10.1117/12.893241

KEYWORDS: Polarization, Wave plates, Polarimetry, Magnesium fluoride, Beam splitters, Modulation, Prototyping, Transmittance, Ultraviolet radiation, Refractive index

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A sounding-rocket program called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is proposed to be launched in the summer of 2014. CLASP will observe the solar chromosphere in Ly-alpha (121.567 nm), aiming to detect the linear polarization signal produced by scattering processes and the Hanle effect for the first time. The polarimeter of CLASP consists of a rotating half-waveplate, a beam splitter, and a polarization analyzer. Magnesium Fluoride (MgF2) is used for these optical components, because MgF2 exhibits birefringent property and high transparency at ultraviolet wavelength. The development and comprehensive testing program of the optical components of the polarimeter is underway using the synchrotron beamline at the Ultraviolet Synchrotron Orbital Radiation Facility (UVSOR). The first objective is deriving the optical constants of MgF2 by the measurement of the reflectance and transmittance against oblique incident angles for the s-polarized and the p-polarized light. The ordinary refractive index and extinction coefficient along the ordinary and extraordinary axes are derived with a least-square fitting in such a way that the reflectance and transmittance satisfy the Kramers-Krönig relation. The reflection at the Brewster's Angle of MgF2 plate is confirmed to become a good polarization analyzer at Ly-alpha. The second objective is the retardation measurement of a zeroth-order waveplate made of MgF2. The retardation of a waveplate is determined by observing the modulation amplitude that comes out of a waveplate and a polarization analyzer. We tested a waveplate with the thickness difference of 14.57 um. The 14.57 um waveplate worked as a half-waveplate at 121.74 nm. We derived that a waveplate with the thickness difference of 15.71 um will work as a half-waveplate at Ly-alpha wavelength. We developed a prototype of CLASP polarimeter using the MgF2 half-waveplate and polarization analyzers, and succeeded in obtaining the modulation patterns that are consistent with the theoretical prediction. We confirm that the performance of the prototype is optimized for measuring linear polarization signal with the least effect of the crosstalk from the circular polarization.

Proceedings Article | 6 October 2011 Paper

The SOLAR-C mission: current status

Toshifumi Shimizu, Saku Tsuneta, Hirohisa Hara, Kiyoshi Ichimoto, Kanya Kusano, Taro Sakao, Takashi Sekii, Yoshinori Suematsu, Tetsuya Watanabe

Proceedings Volume 8148, 81480B (2011) https://doi.org/10.1117/12.893228

KEYWORDS: Magnetism, Solar processes, Space telescopes, Coronagraphy, Telescopes, Spectroscopy, Extreme ultraviolet, Sun, Solar energy, Wind energy

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Proceedings Article | 6 October 2011 Paper

Photon-counting soft x-ray telescope for the Solar-C mission

Taro Sakao, Noriyuki Narukage, Masumi Shimojo, Saku Tsuneta, Yoshinori Suematsu, Satoshi Miyazaki, Shinsuke Imada, Naoto Nishizuka, Kyoko Watanabe, Tadayasu Dotani, Edward DeLuca, Shin-nosuke Ishikawa

Proceedings Volume 8148, 81480C (2011) https://doi.org/10.1117/12.893276

KEYWORDS: X-rays, X-ray telescopes, Mirrors, Coronagraphy, Telescopes, Plasmas, Space telescopes, Magnetism, Sensors, Photons

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Proceedings Article | 6 October 2011 Paper

Overview of Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP)

Noriyuki Narukage, Saku Tsuneta, Takamasa Bando, Ryouhei Kano, Masahito Kubo, Ryoko Ishikawa, Hirohisa Hara, Yoshinori Suematsu, Yukio Katsukawa, Hiroko Watanabe, Kiyoshi Ichimoto, Taro Sakao, Toshifumi Shimizu, Ken Kobayashi, Brian Robinson, Tony Kim, Amy Winebarger, Edward West, Jonathan Cirtain, Bart De Pontieu, Roberto Casini, Javier Trujillo Bueno, Jiri Stepan, Rafael Manso Sainz, Luca Belluzzi, Andres Asensio Ramos, Mats Carlsson

Proceedings Volume 8148, 81480H (2011) https://doi.org/10.1117/12.894290

KEYWORDS: Magnetism, Polarization, Magnesium fluoride, Mirrors, Wave plates, Solar processes, Rockets, Spectrographs, Scattering, Telescopes

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Proceedings Article | 6 August 2010 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 | 12 October 2004 Paper

Development of ultra-light-weight mirror with carbon/carbon composites for optical-IR astronomy

Hajime Takeya, Masami Kume, Steven Hahn, Tsuyoshi Ozaki, Naoki Kohara, Masashi Otsubo, Saku Tsuneta

Proceedings Volume 5487, (2004) https://doi.org/10.1117/12.552304

KEYWORDS: Mirrors, Surface finishing, Composites, Carbon, Plating, Photography, Spherical lenses, Polishing, Electroless plating, Astronomy

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Proceedings Article | 12 October 2004 Paper

The Solar Optical Telescope onboard the Solar-B

Kiyoshi Ichimoto, Saku Tsuneta, Yoshinori Suematsu, Toshifumi Shimizu, Masashi Otsubo, Yoshihiro Kato, Motokazu Noguchi, Masao Nakagiri, Tomonori Tamura, Yukio Katsukawa, Masahito Kubo, Yasushi Sakamoto, Hirohisa Hara, Kenji Minesugi, Akira Ohnishi, Hideo Saito, Noboru Kawaguchi, Tadashi Matsushita, Toshitaka Nakaoji, Kazuhiro Nagae, Joji Sakamoto, Yoshihiro Hasuyama, Izumi Mikami, Keizo Miyawaki, Yasushi Sakurai, Nobuaki Kaido, Toshihida Horiuchi, Sadanori Shimada, Toshio Inoue, Masaaki Mitsutake, Norimasa Yoshida, Osamu Takahara, Norihide Takeyama, Masaharu Suzuki, Shunichi Abe

Proceedings Volume 5487, (2004) https://doi.org/10.1117/12.550989

KEYWORDS: Mirrors, Polarization, Space telescopes, Telescopes, Space operations, Optical telescopes, Optical components, Wavefronts, Temperature metrology, Coating

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Proceedings Article | 12 October 2004 Paper

Image stabilization system on SOLAR-B Solar Optical Telescope

Toshifumi Shimizu, Shin'ichi Nagata, Chris Edwards, Theodore Tarbell, Yasuhiro Kashiwagi, Kazuhide Kodeki, Osamu Ito, Hiroyuki Miyagawa, Masayuki Nagase, Syunsaku Inoue, Kazumasa Kaneko, Yasushi Sakamoto, Kiyoshi Ichimoto, Saku Tsuneta, Shiro Miki, Makoto Endo, Masaki Tabata, Toshitaka Nakaoji, Keiichi Matsuzaki, Ken Kobayashi, Masashi Otsubo, Yoshinori Suematsu, Kazuyoshi Kumagai, Motokazu Noguchi, Tomonori Tamura, Masao Nakagiri

Proceedings Volume 5487, (2004) https://doi.org/10.1117/12.551368

KEYWORDS: Servomechanisms, Mirrors, Control systems, Electronics, Optical telescopes, Space telescopes, Ferroelectric materials, CCD cameras, Telescopes, Sun

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Proceedings Article | 12 October 2004 Paper

Focal plane CCD camera for the X-Ray Telescope (XRT) aboard SOLAR-B

Taro Sakao, Ryouhei Kano, Hirohisa Hara, Keiichi Matsuzaki, Masumi Shimojo, Saku Tsuneta, Takeo Kosugi, Kiyoto Shibasaki, Kazuyoshi Kumagai, Masaki Sawa, Tomonori Tamura, Satoru Iwamura, Mitsuhiko Nakano, Zhangong Du, Kenji Hiyoshi, Michihiro Horii, Leon Golub, Jay Bookbinder, Peter Cheimets, Lawrence Hill, Jerry Owens

Proceedings Volume 5487, (2004) https://doi.org/10.1117/12.551742

KEYWORDS: CCD cameras, Charge-coupled devices, Cameras, Quantum efficiency, X-ray telescopes, Plasmas, Electronics, Telescopes, X-rays, Magnetism

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Proceedings Article | 11 March 2003 Paper

Balloon-borne hard x-ray spectrometer for flare observations

Ken Kobayashi, Saku Tsuneta, Tomonori Tamura, Kazuyoshi Kumagai, Yukio Katsukawa, Masahito Kubo, Takamasa Yamagami, Yoshitaka Saito

Proceedings Volume 4851, (2003) https://doi.org/10.1117/12.461284

KEYWORDS: Sensors, Hard x-rays, Solar processes, Sun, Lead, Electronics, Signal processing, Spectroscopy, Solar energy, X-ray telescopes

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Proceedings Article | 28 August 1998 Paper

Development of the tip-tilt mirror system for the solar XUV telescope

Kazuhide Kodeki, Kazuhiko Fukushima, Toshio Kashiwase, Masao Inoue, Toshifumi Shimizu, Tsuyoshi Yoshida, Taro Sakao, Hirohisa Hara, Shin'ichi Nagata, Ryouhei Kano, Saku Tsuneta

Proceedings Volume 3356, (1998) https://doi.org/10.1117/12.324449

KEYWORDS: Rockets, Mirrors, Telescopes, Extreme ultraviolet, Space telescopes, Sun, Actuators, Content addressable memory, Control systems, Control systems design

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Proceedings Article | 11 July 1997 Paper

Development of multilayer mirrors for the XUV Doppler telescope

Shin'ichi Nagata, Hirohisa Hara, Taro Sakao, Toshifumi Shimizu, Saku Tsuneta, Tsuyoshi Yoshida, Wakana Ishiyama, Katsuhiko Murakami, Tetsuya Oshino

Proceedings Volume 3113, (1997) https://doi.org/10.1117/12.278847

KEYWORDS: Mirrors, Reflectivity, Multilayers, Extreme ultraviolet, Doppler effect, Photomasks, Telescopes, Plasma, Silicon, Space telescopes

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Proceedings Article | 11 July 1997 Paper

XUV Doppler telescope with multilayer optics

Hirohisa Hara, Ryouhei Kano, Shin'ichi Nagata, Taro Sakao, Toshifumi Shimizu, Saku Tsuneta, Tsuyoshi Yoshida, Takeo Kosugi

Proceedings Volume 3113, (1997) https://doi.org/10.1117/12.278872

KEYWORDS: Telescopes, Mirrors, Extreme ultraviolet, Reflectivity, Space telescopes, Charge-coupled devices, Rockets, X-ray telescopes, Doppler effect, Iron

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Proceedings Article | 25 November 1996 Paper

Japanese sounding rocket experiment with the solar XUV Doppler telescope

Taro Sakao, Saku Tsuneta, Hirohisa Hara, Ryouhei Kano, Tsuyoshi Yoshida, Shin'ichi Nagata, Toshifumi Shimizu, Takeo Kosugi, Katsuhiko Murakami, Wakuna Wasa, Masao Inoue, Katsuhiro Miura, Koji Taguchi, Kazuo Tanimoto

Proceedings Volume 2804, (1996) https://doi.org/10.1117/12.259721

KEYWORDS: Mirrors, Telescopes, Space telescopes, Extreme ultraviolet, Rockets, Charge-coupled devices, Multilayers, Doppler effect, Solar processes, Coronagraphy

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Proceedings Article | 25 November 1996 Paper

New high-thermal-conductivity composite material for high-precision space optics

Tsuyoshi Ozaki, Chihiro Ikeda, Minoru Isoda, Saku Tsuneta

Proceedings Volume 2804, (1996) https://doi.org/10.1117/12.259709

KEYWORDS: Composites, Optical fibers, Absorption, Astronomical imaging, Thermal modeling, Glasses, Temperature metrology, Mirrors, Optical telescopes, Curium

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Showing 5 of 22 publications

Conference Committee Involvement (1)

Optical, Infrared, and Millimeter Space Telescopes

21 June 2004 | Glasgow, United Kingdom

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