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X-ray Source Catalog on Microfilm


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)


This data set is a catalog of sources on microfiche as observed by the HEAO A-1 Large Area Sky Survey Experiment. The catalog is derived from the first six months of data from HEAO A-1, during which time one scan of the entire sky was completed. Positions and intensities for 842 sources are cataloged, with a limiting flux of 250 nJy at 5 keV, or about 0.25 UFU. The catalog is more than 90% complete at a flux level equivalent to 1.5 Jy at 5 keV, for a Crablike spectrum. Included are source positions in 1950.0 RA and Dec, plus the four corners of a 95% confidence error box and the solid angle enclosed by the error box, position in galactic and ecliptic longitude and latitude, apparent source intensity, and identification of the source with other cataloged objects.

Included in the data set is a description of the HEAO A-1 instrument, a description of data summation, and source-fitting techniques used to extract the source specifications appearing in the catalog. A machine-readable version of this data set is available under NSSDC data set ID ASXR-00066. For further information on data listed in this catalog, contact Dr. Kent Wood, Code 4121, Naval Research Laboratory, Washington, DC 20375.

Alternate Names

  • HEAO A-1 X-ray Source Catalog


  • Astronomy: X-Ray


  • 77-075A-01A
  • SX-D1G

Additional Information



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



NameRoleOriginal AffiliationE-mail
Dr. Kent S. WoodData ProviderUS Naval Research
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