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The OSO-8 Satellite

artist concept of OSO-8
Credit: NASA

The 8th Orbiting Solar Observatory (OSO-8) was launched on 21 June 1975. While OSO-8's primary objective was to observe the Sun, four instruments were dedicated to observations of other celestial X-ray sources brighter than a few milliCrab. OSO-8 ceased operations on 1 October 1978.

Mission Characteristics

* Lifetime: 21 June 1975 - 1 October 1978
* Energy Range: 0.15 keV - 1 MeV
* Payload:
  • GSFC Cosmic X-Ray Spectroscopy Experiment (GCXSE)
    Detector A (2-60 keV): Eff. area = 263 cm2, FOV = 5°
    Detector B (2-20 keV): Eff. area = 37 cm2, FOV = 3°
    Detector C (2-60 keV): Eff. area = 237 cm2, FOV = 5°
  • High Energy Celestial X-ray Experiment
    0.01-1 MeV eff. area 27.5 cm2, FOV 5°
  • Soft X-ray Background Radiation Experiment
    0.15-45 keV eff. area 51.8 cm2, 43.0 cm2, 41.7 cm2, FOV 2.7° with 3° spatial resolution
  • Graphite Crystal X-ray Spectrometer
    2-8 keV, FOV 3°
* Science Highlights:
  • Iron-line detection in the X-ray spectra of a cluster of galaxies.
  • Detection of Black-Body spectrum from X-ray bursts.
  • Set upper limit on the polarization of radiation from several X-ray binaries.
* Archive: Lightcurves and Raw data from the GCXSE.

[About OSO-8] ( [Archive] ( [Gallery] ( [Publications] (

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