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X-Ray and EUV Spectroheliograph (2 to 400 A)

NSSDCA ID: 1971-083A-01

Mission Name: OSO 7
Principal Investigator:Dr. Werner M. Neupert


The objective of this experiment was to determine the distribution of matter and temperature in the corona above solar active regions and determine how this matter changes during solar flares. Four distinct instruments were used. The first was a grazing-incidence spectrometer with a spectral resolution of 1.0 A, used to cover the range 120 to 400 A. The various discrete wavelengths were detected by three Bendix electron multipliers mounted on a moving carriage. Second, a long X-ray spectroheliograph with a bandpass of 2 A was used to cover the range 8 to 15 A. The third instrument was a short X-ray spectroheliograph, used to cover the range 1.7 to 8.0 A. Both X-ray spectroheliographs used the balanced filter method. Fourth, a polarimeter using the scattering technique was used to cover the 20 to 40 keV range. The spatial resolution of the EUV spectroheliograph was 10 x 20 arc seconds. The spatial resolution of X-ray spectroheliographs was 20 x 20 arc seconds. The short EUV detector failed in March 1972. The medium EUV detector sensitivity started dropping during October 1972, and by March 1973 was 60 percent of the original value. The long EUV detector degraded to the point that it no longer produced useful scientific data as of May 1973. Only real-time data were obtained after May 18, 1973 when the spacecraft tape recorder failed.

Alternate Names

  • OSO7/X-RayandEUVSpectroheliograph_2to400A_
  • Solar EUV and Soft X-Ray Radiation in the Ranges between 6-25 A and 170-400 A

Funding Agency

  • NASA-Office of Space Science (United States)


  • Solar Physics: X-Ray
  • Solar Physics: Ultraviolet

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Mr. William A. WhiteGeneral ContactNASA Goddard Space Flight Center
Dr. James H. UnderwoodOther InvestigatorAerospace Corporation
Dr. Robert D. ChapmanOther InvestigatorNASA Goddard Space Flight
Dr. Roger J. ThomasOther InvestigatorNASA Goddard Space Flight Center
Dr. Werner M. NeupertPrincipal InvestigatorNASA Goddard Space Flight
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