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ROSAT : The Roentgen Satellite

artist concept of ROSAT
Credit: NASA

The Roentgen Satellite, ROSAT, a Germany/US/UK collaboration, was launched on June 1, 1990 and operated for almost 9 years. The first 6 months of the mission were dedicated to the all sky-survey (using the Position Sensitive Proportional Counter detector), followed by the pointed phase. The survey obtained by ROSAT was the first X-ray and XUV all-sky survey using an imaging telescope with an X-ray sensitivity of about a factor of 1000 better than that of UHURU. During the pointed phase ROSAT made deep observations of a wide variety of objects.

Mission Characteristics

* Lifetime: 1 June 1990 - 12 February 1999
* Energy Range: X-ray 0.1 - 2.5 keV , EUV 62-206 eV
* Special Feature: All sky-survey in the soft X-ray band
* Payload:
  • An X-ray telescope used in conjunction with one of the following instruments (0.1-2.5 keV)
    • Position Sensitive Proportional Counter
      (PSPC) 2 units : detector B, used for the pointed phase, & detector C ,used for the survey
      FOV 2 ° diameter eff area 240 cm2 at 1 keV
      energy resolution of deltaE/E=0.43 (E/0.93)-0.5
    • High Resolution Imager (HRI)
      FOV 38 ' square ; eff area 80 cm2 at 1 keV
      ~ 2 arcsec spatial resolution (FWHM)
  • A Wide Field Camera with its own mirror system
    (62-206 eV) FOV 5 ° diameter
* Science Highlights:
  • X-ray all-sky survey catalog, more than 150000 objects
  • XUV all-sky survey catalog (479 objects)
  • Source catalogs from the pointed phase (PSPC and HRI) containing ~ 100000 serendipitous sources
  • Detailed morphology of supernova remnants and clusters of galaxies.
  • Detection of shadowing of diffuse X-ray emission by molecular clouds.
  • Detection (Finally!) of pulsations from Geminga.
  • Detection of isolated neutron stars.
  • Discovery of X-ray emission from comets.
  • Observation of X-ray emission from the collision of Comet Shoemaker-Levy with Jupiter.
* Archive: Catalogs, Spectra, Lightcurves, Images and Raw data

[ROSAT Guest Observer Facility] (

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