The 1.8 meter spacewatch telescope motion control system

M. Perry, T. Bressi, R. McMillan, A. Tubbiolo, L. Barr

Research output: Contribution to journalConference articlepeer-review

5 Scopus citations


The 1.8 meter Spacewatch telescope and its building on Kitt Peak were dedicated on June 7, 1997 for the purpose of finding previously unknown asteroids and comets. Drift-scanning large areas of sky with a CCD will be done at rates up to 10 times that of the sidereal rate over angles up to 60 degrees of arc along great circles at various orientations. The primary mirror and cell around which the telescope are designed are from the Multi-Mirror Telescope (MMT) on Mt. Hopkins in Arizona. The telescope's friction drive system allows backlash-free control of its altitude-over-azimuth mount. The mount features bearings of small radii and plenty of motor torque to compensate for wind buffeting. Both incremental and absolute encoders will be used; the absolute encoders will update the position derived from incremental encoders to compensate for the microslipping that is an unavoidable consequence of a friction drive. The control system features commercially produced servo controller cards that are programmed from a user interface program running in a PC under DOS. Realtime operation of the drive is controlled by the interface cards, leaving the PC free to run the display of the position readout and accept keyboard input from the observer without interfering with the drive. It is believed that this design offers the greatest flexibility and accuracy for our search programs.

Original languageEnglish (US)
Pages (from-to)450-465
Number of pages16
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1998
EventTelescope Control Systems III - Kona, HI, United States
Duration: Mar 20 1998Mar 21 1998

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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