The Soft X-Ray Telescope for the Solar a Mission

  1. J. H. Waite Jr.,
  2. J. L. Burch and
  3. R. L. Moore
  1. M.E. Bruner1,
  2. L.W. Acton1,
  3. W.A. Brown1,
  4. R.A. Stern1,
  5. T. Hirayama2,
  6. S. Tsuneta2,
  7. T. Watanabe2 and
  8. Y. Ogawara3

Published Online: 18 MAR 2013

DOI: 10.1029/GM054p0187

Solar System Plasma Physics

Solar System Plasma Physics

How to Cite

Bruner, M.E., Acton, L.W., Brown, W.A., Stern, R.A., Hirayama, T., Tsuneta, S., Watanabe, T. and Ogawara, Y. (1989) The Soft X-Ray Telescope for the Solar a Mission, in Solar System Plasma Physics (eds J. H. Waite, J. L. Burch and R. L. Moore), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM054p0187

Author Information

  1. 1

    Lockheed Palo Alto Research Laboratory, Palo Alto, California, U.S.A. 94304

  2. 2

    National Astronomical Observatory of Japan, Mitaka, Tokyo, Japan

  3. 3

    Institute for Space and Astronautical Sciences, Sagamihara, Japan

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875900742

Online ISBN: 9781118664315



  • Space plasmas;
  • Sun;
  • Magnetosphere;
  • Astrophysics


The Solar A mission, being conducted by the Japanese Institute for Astronautical and Space Sciences, is a project to study solar flares using a cluster of instruments on an orbiting satellite. It is scheduled to be launched in September or October of 1991. The emphasis of the mission is on imaging and spectroscopy of hard and soft X-rays. The Soft X-Ray Telescope (SXT), one of two major imaging instruments on the satellite, is a joint U.S.-Japan project. It is being prepared at Lockheed under NASA sponsorship. The electronic control system for the SXT is based on microprocessors and is a joint effort between Lockheed and the National Astronomical Observatory of Japan (NAOJ). The SXT uses a glancing incidence telescope of 1.55 m effective focal length to form images in the 0.25 to 3.0 keV range on a 1024×1024 virtual phase CCD detector. A selection of thin metallic filters located near the focal plane provides the capability for electron temperature diagnostics. Knowledge of the alignment of soft X-ray images with respect to features observable in visible light is provided by a coaxially mounted aspect telescope which forms its image on the CCD sensor when the thin metallic filter is replaced by an appropriate glass filter. A novel mechanical design has permitted a very lightweight structure that remains stiff enough to survive the severe launch environment. Other Solar A instruments include a hard X-ray telescope, a Bragg crystal spectrometer, a wide band spectrometer, and a radiation belt monitor.