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Filtering by: Creator Ren, Deqing Remove constraint Creator: Ren, Deqing

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  • 9k41zh65s?file=thumbnail
    Article
    Ren, Deqing
    Solar-adaptive optics (AO) are more challenging than nighttime AO, in some aspects. A portable solar adaptive optics (PSAO) system featuring compact physical size, low cost, and good performance has been proposed and developed. PSAO can serve as a vis . . .
  • 2n49t495j?file=thumbnail
    Article
    Zhu, Yongtian
    High-contrast imaging provided by a coronagraph is critical for the direction imaging of the Earth-like planet orbiting its bright parent star. A major limitation for such direct imaging is the speckle noise that is induced from the wave-front error o . . .
  • Work
    Article
    Dou, Jianpei
    Solar conventional adaptive optics (CAO) with one deformable-mirror uses a small field-of-view (FOV) for wave-front sensing, which yields a small corrected FOV for high-resolution imaging. Solar activities occur in a two-dimensional extended FOV and s . . .
  • G732dd06r?file=thumbnail
    Article
    Zhang, Xi
    An adaptive optics (AO) system based on stochastic parallel gradient descent (SPGD) algorithm is proposed to reduce the speckle noises in the optical system of stellar coronagraph in order to further improve the contrast. The principle of SPGD algorit . . .
  • X920g081c?file=thumbnail
    Article
    Sharples, Ray
    A prototype of a multiway fibre bundle connector for astronomical applications is described. The connector provides for connection and disconnection in the fiber trains that feed an astronomical spectrograph. It also provides the more important functi . . .
  • Work
    Article
    Zhu, Yongtian
    We propose a coronagraph for direct imaging of Earth‐like planets orbiting nearby bright stars. The coronagraph is based on an apodization pupil composed of two stepped‐transmission filters. We show that the coronagraph can achieve 10−10 high‐contrast . . .
  • Work
    Article
    Zhang, Xi
    Multi-conjugate adaptive optics (MCAO) can considerably extend the corrected field of view with respect to classical adaptive optics, which will benefit solar observation in many aspects. In solar MCAO, the Sun structure is utilized to provide multipl . . .
  • Work
    Article
    Zhu, Yongtian
    We propose a coronagraph for direct imaging of Earth‐like planets orbiting nearby bright stars. The coronagraph is based on an apodization pupil composed of two stepped‐transmission filters. We show that the coronagraph can achieve 10−10 high‐contrast . . .
  • Q811kn35g?file=thumbnail
    Article
    Ren, Deqing
    A method based on the Herzberger approach has been investigated for the selection of glasses for the apochromatic correction at near-infrared (NIR) wavelength. The method avoids the algebraic complexity and simplifies the glass selection processes. Do . . .
  • 4x51hm92p?file=thumbnail
    Article
    Zhu, Yongtian
    Polarimetry plays an important role in the measurement of solar magnetic fields. We developed a high-sensitivity and high-accuracy polarimeter (HHP) based on nematic liquid crystal variable retarders (LCVRs), which has a compact setup and no mechanica . . .