The OSO-8 Satellite

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

• 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°

• 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.