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\citation{mai00,kim03}
\citation{gil00}
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\citation{gil03}
\citation{brz04}
\citation{brz04}
\citation{eto04,iwa06}
\citation{lew03,dal06}
\citation{gra03,gra04}
\citation{brz04}
\citation{brz04}
\@writefile{toc}{\contentsline {section}{\numberline {1}INTRODUCTION}{1}}
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\citation{gil03}
\citation{brz04}
\@writefile{lof}{\contentsline {figure}{\numberline {1}{\ignorespaces  Left) drawing of one module of the fiber positioner from Fig. 4 of Ref\citen  {brz04}. One module has 20$\times $2 science-fibers and 2 guide-bundles at both ends of the module. Science-fibers are 100$\mu $m diameter core fiber, and guide-bundles are bundles of 7 50$\mu $m-core fibers with 80$\mu $m spacing, which corresponds to $0.96^{\prime \prime }$ at the focal plane. A fiber is attached to a carbon-fiber tubing, called ``spine'', with a pivoting ball and a tungsten counter weight. The pivoting ball is sitting on a three-point mount with a ring magnet at the top of a quadrant tube piezo actuator. Spines for the science-fibers and the guide-bundles have the same structure. Middle) close up view of the focal plane. 12 modules of the 40 science-fibers cover the FoV. 400 science-fibers within the 30$^{\prime }$ diameter FoV are connected to the spectrographs. The spacing between neighboring spines is 7mm. Each spine is designed to be able to reach the home positions the 6 neighboring spines. Right) structure of the Echidna unit around the focal plane. The positions of the tips of the fibers are measured with the fiber camera of the Focal Plane Imager (FPI) on the XY gantry. }}{2}}
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\@writefile{toc}{\contentsline {section}{\numberline {2}MECHANICAL PROPERTIES}{2}}
\@writefile{toc}{\contentsline {subsection}{\numberline {2.1}Accuracy of the measurements of the fiber positions}{2}}
\citation{brz04}
\@writefile{lof}{\contentsline {figure}{\numberline {2}{\ignorespaces  Left) Echidna unit on the testing jig (orange frame structure). The bottom of the unit corresponds to the focal plane. The black box on the table in front of the unit is the fiber connector assembly. Right) Echidna under installation into the prime-focus unit. The installation is done off the telescope in the prime-focus unit storage area and attached to the telescope, Echidna being enclosed in the unit. }}{3}}
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\@writefile{lof}{\contentsline {figure}{\numberline {3}{\ignorespaces  Plots of percentage energy encircled within a 100$\mu $m diameter circle as a function of misalignment for three different seeing conditions. }}{3}}
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\@writefile{lof}{\contentsline {figure}{\numberline {4}{\ignorespaces  Left) Residuals in one FoV of the spine-camera after removing third order distortion. No systematic residual. Middle) residuals in the entire focal plane after removing the camera distortion model and the gantry XY movement non-orthogonality model. Right) The differences of the measured positions of spine tips in two measurements. }}{4}}
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\@writefile{lof}{\contentsline {figure}{\numberline {5}{\ignorespaces  Results of the parfocality measurements. The black dots and blue circles represents the measurements for the science-fibers and the guide-bundles, respectively. The red solid line represent the best focus position, and the thin sold lines indicate $\pm 100\mu $m and $\pm 150\mu $m from the best focus. }}{4}}
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\@writefile{toc}{\contentsline {subsection}{\numberline {2.2}Length of the spines}{4}}
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\@writefile{lof}{\contentsline {figure}{\numberline {6}{\ignorespaces  Variation of the positions of the tips of the science-fibers (black dots) and the guide-bundles (light-blue circles) following the change of the tilt angle. The tilt angle changes are indicated at top of the each panel. In these measurements, X-axis corresponds to the direction of gravity. Several spines show very large offset due to slippages of their pivot ball during the tilt movement. }}{5}}
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\@writefile{toc}{\contentsline {subsection}{\numberline {2.3}Flexure of the spines}{5}}
\@writefile{toc}{\contentsline {subsection}{\numberline {2.4}Fiber position stability}{5}}
\@writefile{lof}{\contentsline {figure}{\numberline {7}{\ignorespaces  The magnitude of relative deflection between the tilt angle of 0 degrees to 60 degrees. Measurements at 4 different rotation angles are shown with different line types. }}{6}}
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\@writefile{lof}{\contentsline {figure}{\numberline {8}{\ignorespaces  Fiber position stability measured at tilt angle of 60 degree. Left) Position difference in the first two hours, Right) Position difference between the two and four hours. }}{6}}
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\@writefile{toc}{\contentsline {section}{\numberline {3}DYNAMICAL PROPERTIES}{6}}
\@writefile{toc}{\contentsline {subsection}{\numberline {3.1}Step-size with large step numbers}{6}}
\@writefile{lof}{\contentsline {figure}{\numberline {9}{\ignorespaces  Step sizes measured in the X$+$ movement. Upper panels) for coarse mode operation. Left and right panels are for tilt angle 0 degree vs. 30 degree and 0 degree vs. 60 degree, respectively. Lower panels) for fine mode operation. Left and right panels are for tilt angle 0 degree vs. 30 degree and 0 degree vs. 60 degree, respectively. }}{7}}
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\@writefile{toc}{\contentsline {subsection}{\numberline {3.2}Accuracy of open-loop ``tweaking''}{7}}
\@writefile{toc}{\contentsline {subsection}{\numberline {3.3}Fiber configuration results}{7}}
\@writefile{lof}{\contentsline {figure}{\numberline {10}{\ignorespaces  Left) Average spine step size with 1-step fine-mode movement vs. the difference between one measurement and the mean result, i.e. 0.2 corresponds to 20\% stepsize variation in one measurement. Middle) for 5-step movement. Right) for 10-step movement. }}{8}}
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\@writefile{toc}{\contentsline {section}{\numberline {4}ON SKY COMMISSIONING RESULTS AND PROSPECTS}{8}}
\@writefile{toc}{\contentsline {subsection}{\numberline {4.1}Echidna performance at summit and on-sky commissioning}{8}}
\@writefile{lof}{\contentsline {figure}{\numberline {11}{\ignorespaces  Results of 7-iteration positioning tests from home position to a random position. The horizontal axis shows logarithmic distance from target in microns. Thus 1 and 4 means 10$\mu $m and 10mm, respectively. The number of spines as a function of distance from their targets are shown in the histograms. }}{9}}
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\@writefile{lof}{\contentsline {figure}{\numberline {12}{\ignorespaces  Positioning record of spine residuals larger than 10$\mu $m in a positioning test. Left panels are 14mm$\times $14mm fov and right panels are 120$\mu $m$\times $120$\mu $m fov. The blue points indicate starting position and the red points indicate the final position after 7 iterations. The large circles in the right panels indicate 10$\mu $m from the target. }}{9}}
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\citation{kim06}
\citation{zac04}
\citation{zac04}
\@writefile{lof}{\contentsline {figure}{\numberline {13}{\ignorespaces  Left) Measured position of the center of the distortion pattern on the focal plane. During the observation, the corrector itself was on the optical axis of the primary mirror. It should be noted that the fibers rotate with the instrument rotator, but the optical axis and the distortion pattern do not. Right) Residual distortion pattern after removing the distortion pattern and the shift of the distortion pattern. Measured in NGC2682. The targets are selected from UCAC2 astrometry catalog\cite  {zac04}. The positional errors are about 20mas for the stars in the 10 to 14 magnitude range, with about 70mas at the limiting magnitude of $R$ about 16 mag. }}{10}}
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\@writefile{toc}{\contentsline {subsection}{\numberline {4.2}Distortion pattern measurements with the sky-camera}{10}}
\@writefile{toc}{\contentsline {subsection}{\numberline {4.3}Acquiring stars with the guide-bundles}{10}}
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\@writefile{lof}{\contentsline {figure}{\numberline {14}{\ignorespaces  Guide fiber bundle image taken during the May 2008 commissioning run. 10 stars are acquired with the guide bundle. Each bundle consists of 7$\times $50$\mu $m diameter fibers. The positions of the 7 fibers of the 14 bundles are marked with circles. }}{11}}
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\@writefile{toc}{\contentsline {subsection}{\numberline {4.4}Measuring the distortion pattern using the science fibers}{11}}
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\bibcite{dal06}{10}
\bibcite{gra03}{11}
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\@writefile{lot}{\contentsline {table}{\numberline {1}{\ignorespaces  Summary of the desired and current positioning accuracy of the instrument. }}{12}}
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