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Galactic Monitor Experiment (GME)

NSSDCA ID: 1975-037A-02

Mission Name: SAS-C
Principal Investigator:Dr. George W. Clark


The objectives of this experiment were to locate galactic X-ray sources to 15 arc-s and to monitor these sources for intensity variations. The source positions were determined with the use of the modulation collimators of the Extragalactic Experiment during the nominal 2-month observation of the galactic equator. The monitoring of the X-ray sky was accomplished by the use of three slat collimators. One collimator, 1- by 70-deg FWHM, was oriented perpendicular to the equatorial plane of the satellite, while the other two, each 0.5- by 45-deg FWHM, were oriented 30 deg above and 30 deg below the first. The detector behind each collimator was a proportional counter, sensitive from 1.5 to 13 keV, with an effective area of about 100 sq cm. The 1.0-deg collimator had an additional counter of the same area, sensitive from 8 to 50 keV. Three lines of position were obtained for any given source when the satellite was being spun at a steady rotation of 4 arc-min/s about the Z axis. For additional information, see W. H. G. Lewin et al., Ap. J., v. 207, p. L95, 1976.

Alternate Names

  • GME

Facts in Brief

Mass: 75.3 kg
Power (avg): 17.5 W

Funding Agency

  • NASA-Office of Space Science (United States)


  • Astronomy: X-Ray

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Robert W. RascheGeneral ContactMassachusetts Institute of
Dr. Hale V. BradtOther InvestigatorMassachusetts Institute of
Dr. Walter H. G. LewinOther InvestigatorMassachusetts Institute of
Dr. Herbert W. SchnopperOther InvestigatorDanish Space Research Institute
Dr. George W. ClarkPrincipal InvestigatorMassachusetts Institute of
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