Conceptual Design of a Compact Fizeau Interferometer

download Conceptual Design of a Compact Fizeau Interferometer

of 9

  • date post

    03-Jan-2016
  • Category

    Documents

  • view

    16
  • download

    1

Embed Size (px)

description

Conceptual Design of a Compact Fizeau Interferometer. Neng-hong Zhu, Xin-yang Chen Shanghai Astronomical Observatory 2014/11/2. Background & Goal. Dream: Optical long baseline interferometer based in space Reality: Optical interferometry of China is just in inital stage - PowerPoint PPT Presentation

Transcript of Conceptual Design of a Compact Fizeau Interferometer

  • Conceptual Design of a Compact Fizeau InterferometerNeng-hong Zhu, Xin-yang Chen

    Shanghai Astronomical Observatory*

  • Background & GoalDream: Optical long baseline interferometer based in spaceReality: Optical interferometry of China is just in inital stage + limited moneyOption: Compact Fizeau Space Interferometershort baselinedirect instantaneous imagingsmall scale Step 1: gound prototype with diameter equivalent to 1m Step 2:Fizeau space Interferometer with diameter equivalent to 2~4m future:longer baseline & more elements...

  • Array configurationGeometric ArrayModulation Transfer Function: MTF=|FT(PSF)|

  • Beam combining errors (1/2)PSF vs. piston error piston=-0.2piston=-0.4piston=0.2piston=0.4MTF vs. pistonStrehl Ratio vs. pistonSR0.9 -----> piston P-V0.1

    [Cao Fang, et al, 2008]

  • Beam combining errors (2/2)PSF vs. tip/tilt error

    X tip=0

    aY Tilt Error=0 bY Tilt Error=0.1 (cY Tilt Error=0.2 (d) Y Tilt Error=0.3 X tip=0.2 X tip=0.1 X tip=0.3 Y tilt=0 Y tilt=0.2 Y tilt=0.1 Y tilt=0.3MTF vs. tip/tiltStrel Ratio vs. tip/tiltSR0.9 -----> tip/tilt P-V0.0550.3"

    [Cao Fang, et al, 2008]

  • Spec. of the ground prototype

    Y-4 array -----> (1) high stability due to symmetric structure (2) optimal MTF (3) tubes modulizationcommon mounting -----> without optical delay line for compensating outer OPDC-shape board & triangle flatform -----> high stiffness & resonance freq. wide FOV ~ 2 'Direct Drive -----> no backlash, high tracking accuracy ~ RMS:0.01"(Dec=45)

  • FEA of structure

  • Optics designsub-telescope opticsfolding & combiner opticsconfusion circle 0.7"

    Primary mirror Outer diameter(mm)420Inner diameter(mm)80Thickness(mm)60Weight (Kg)20f/D ratio 2Eccentricity1.020466Secondary mirrorOuter diameter(mm)80Curvature radii336Thickness(mm)15Weight (Kg)0.15Eccentricity2.076363

  • ChallengeHow to measure and eliminate co-phasing errors between sub-telescopes?pyramid wavefront sensorfringe tracking

    How to improve image quality?interferometric image restoration method -> better MTF