Image Stabilization System for Hinode (Solar-B) Solar Optical Telescope

Shimizu, Toshifumi; Nagata, Shinji; Tsuneta, S.; Tarbell, T. D.; Edwards, Christopher G.; Shine, R. A.; Hoffmann, C.; Thomas, Emma Miriam; Sour, S.; Rehse, R.; Ito, Osamu; Kashiwagi, Yukiyasu; Tabata, Masaki; Kodeki, Kazuhide; Nagase, Masayuki; Matsuzaki, Keiichi; Kobayashi, K.; Ichimoto, Kiyoshi; Suematsu, Y.

doi:10.1007/978-0-387-88739-5_10

Cited by 16 publications

(19 citation statements)

References 3 publications

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“…The OTA is a diffraction-limited Gregorian telescope with a diameter of 50 cm which is the largest solar optical telescope in space, and the FPP includes the Narrowband Filter Imager (NFI), the Broadband Filter Imager (BFI), and the Spectro-Polarimeter (SP). The SOT provides unprecedented high-resolution photometric and vector magnetic images of the photosphere and chromosphere with a very stable point spread function and is equipped with an image stabilization system (Shimizu et al 2008) with the performance better than 0.01 arcsec rms. The BFI produces photometric images with broad spectral resolution in six bands (CN band, Ca II H line, G band, and three continuum bands) at the highest spatial resolution available from the SOT (0.0541 arcsec pixel −1 sampling) and at a rapid cadence (< 10 s) over a 218 × 109 arcsec FOV.…”

Section: Observation and Data Analysismentioning

confidence: 99%

Estimation of Spicule Magnetic Field Using Observed MHD Waves by the Hinode Sot

Kim

Bong²,

Park³

et al. 2008

Journal of The Korean Astronomical Society

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Using the MHD coronal seismology technique, we estimated the magnetic field for three spicules observed in 2008 June. For this study, we used the high resolution Ca II H line (3968.5Å) images observed by the Hinode SOT and considered a vertical thin flux tube as a spicule model. To our knowledge, this is the first attempt to estimate the spicule magnetic field using the Hinode observation. From the observed oscillation properties, we determined the periods, amplitudes, minimum wavelengths, and wave speeds. We interpreted the observed oscillations as MHD kink waves propagating through a vertical thin flux tube embedded in a uniform field environment. Then we estimated spicule magnetic field assuming spicule densities. Major results from this study are as follows : (1) we observed three oscillating spicules having durations of 5-7 minutes, oscillating periods of 2-3 minutes, and transverse displacements of 700-1000 km. (2) The estimated magnetic field in spicules is about 10-18 G for lower density limit and about 43-76 G for upper density limit. (3) In this analysis, we can estimate the minimum wavelength of the oscillations, such as 60000 km, 56000 km, and 45000 km. This may be due to the much longer wavelength comparing with the height of spicules. (4) In the first event occurred on 2008 June 03, the oscillation existed during limited time (about 250 s). This means that the oscillation may be triggered by an impulsive mechanism (like low atmospheric reconnection), not continuous. Being compared with the ground-based observations of spicule oscillations, our observation indicates quite different one, i.e., more than one order longer in wavelength, a factor of 3-4 larger in wave speed, and 2-3 times longer in period.

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Section: Observation and Data Analysismentioning

confidence: 99%

Estimation of Spicule Magnetic Field Using Observed MHD Waves by the Hinode Sot

Kim

Bong²,

Park³

et al. 2008

Journal of The Korean Astronomical Society

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“…The research has focused on many aspects related to microvibrations, starting with the sources [7,8], and throughout the years various methodologies have been proposed for their modelling and control [9][10][11][12], e.g., simulating the interface between sources and spacecraft structures and predicting payload pointing errors [13,14]. Among the difficulties related to microvibrations, one of the main ones is their analysis, having to deal with extremely low amplitudes (µg) and a bandwidth that goes up to several hundred Hz.…”

Section: Introductionmentioning

confidence: 99%

Modelling the effect of electrical harness on microvibration response of structures

2015

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“…The microvibrations produced by reaction/momentum wheel assemblies (R/MWA) onboard spacecraft, for example reaction/momentum wheel assemblies (R/MWA), cryo-coolers, thrusters, solar array drive mechanisms, and mobile mirrors, can degrade the performance of instruments with high pointing precision and stability [1][2][3][4]. These disturbances are attracting more and more attentions, because they are significant in the 1k Hz frequency range [5] and excite flexible modes of the spacecraft, which cannot be controlled or reduced by the attitude and orbit control systems.…”

Section: Introductionmentioning

confidence: 99%

Improving Performance of Cantilevered Momentum Wheel Assemblies by Soft Suspension Support

Zhou

2013

Shock and Vibration

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Abstract. This paper focuses on improving the performance of the rigid support cantilevered momentum wheel assemblies (CMWA) by soft suspension support. A CMWA, supported by two angular contact ball bearings, was modeled as a Jeffcott rotor. The support stiffness, before and after in series with a linear soft suspension support, were simplified as two Duffing's type springs respectively. The result shows that the rigid support CMWA produces large disturbance force at the resonance speed range. The soft suspension CMWA can effectively reduce the force on the bearing (also disturbance forces produced by the CMWA) at high rotational speed, and also reduce the nonlinear characteristic of the stiffness. However, the instability of the soft suspension CMWA will limit the maximum rotational speed of the CMWA. Thus, a "proper" stiffness of the soft suspension system is a trade-off strategy between reduction of the force and extension of the speed range simultaneously.Keywords: Cantilevered momentum wheel assemblies, ball bearing, soft suspension support, in series, instability, imbalance Radius obtained by liner model r:Displacement of the axis centre r 0

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Image Stabilization System for Hinode (Solar-B) Solar Optical Telescope

Cited by 16 publications

References 3 publications

Estimation of Spicule Magnetic Field Using Observed MHD Waves by the Hinode Sot

Estimation of Spicule Magnetic Field Using Observed MHD Waves by the Hinode Sot

Modelling the effect of electrical harness on microvibration response of structures

Improving Performance of Cantilevered Momentum Wheel Assemblies by Soft Suspension Support

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