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Proceedings Paper

Improvement of the pointing accuracy of the Subaru Telescope by suppressing vibrations
Author(s): Tomio Kanzawa; Daigo Tomono; Tomonori Usuda; Naruhisa Takato; Satoru Negishi; Shinji Sugahara; Noboru Itoh
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Paper Abstract

The Subaru Telescope has been operated smoothly for eight years after its first light. With the advent of instruments with high spatial resolution such as the adaptive optics, elongation of images has been noticed towards specific azimuth (AZ) and elevation (EL). With accelerometers with high time resolution, we detected vibrations of the telescope and could attribute the elongation of images to the vibrations. The detected vibrations are at 3.6 Hz and at 7-9 Hz in AZ direction and at 5-6 Hz in EL direction. Image motion due to these vibrations is 0.4 arcsec peak-to-peak at maximum, which is not negligible compared to image motion of 0.063 arcsec rms in quiescent state. The motion, which can not be canceled with the auto guider, results in elongation of images. The 3.6 Hz vibration in AZ direction is only excited while culmination EL of above 80 degrees. The 7-9 Hz vibration in AZ direction and the 5-6 Hz vibration in EL direction are excited by periodic errors in incremental encoders which are used to measure velocity of telescope rotation. We investigated possibilities to reduce the vibrations with tuning control loops of the AZ and EL axes.

Paper Details

Date Published: 11 July 2006
PDF: 10 pages
Proc. SPIE 6267, Ground-based and Airborne Telescopes, 62673J (11 July 2006); doi: 10.1117/12.670629
Show Author Affiliations
Tomio Kanzawa, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Daigo Tomono, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Tomonori Usuda, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Naruhisa Takato, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Satoru Negishi, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Shinji Sugahara, Mitsubishi Electric Corp. (Japan)
Noboru Itoh, Mitsubishi Electric Corp. (Japan)


Published in SPIE Proceedings Vol. 6267:
Ground-based and Airborne Telescopes
Larry M. Stepp, Editor(s)

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