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Diffuse Infrared Background Experiment (DIRBE)

NSSDCA ID: 1989-089A-02

Mission Name: COBE
Principal Investigator:Dr. Michael G. Hauser


The diffuse IR background experiment (DIRBE) consists of a cryogenically cooled (to 2 deg K) multiband radiometer used to investigate diffuse infrared radiation from 1 to 300 micrometers. The instrument measures the absolute flux in 10 wavelength bands with a 1-deg field of view pointed 30 deg off the spin axis. Detectors (photoconductors) and filters for the 8 to 100 micrometer channels are the same as for the IRAS mission. Bolometers are used for the longest wavelength channel (120 to 300 micrometers). The DIRBE sensitivity will be better than 2E-12 W/(sq cm-sr) in channels 1 to 3. Channels 4 to 8 will reach 6E-13 while channels 9 and 10, with their less sensitive bolometers but larger etendue, will reach 4E-12. These limits are achievable with existing detectors cooled to near the cryostat temperature of 1.6 deg K. The telescope is a well baffled, off-axis, Gregorian flux collector with re-imaging. The instrument weighs approximately 34 kg, uses 100 W and has a data rate of 1700 bps.

Alternate Names


Facts in Brief

Mass: 14 kg
Power (avg): 100 W
Bit rate (avg): 1.7 kbps

Funding Agency

  • NASA-Office of Space Science (United States)


  • Astronomy: Infrared

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Samuel GulkisOther InvestigatorNASA Jet Propulsion
Dr. John C. MatherOther InvestigatorNASA Goddard Space Flight
Dr. Rainer WeissOther InvestigatorMassachusetts Institute of
Dr. George F. Smoot, IIIOther InvestigatorLawrence Berkeley
Dr. David T. WilkinsonOther InvestigatorPrinceton University
Dr. Michael G. HauserPrincipal InvestigatorNASA Goddard Space Flight

Selected References

  • Wright, E. L., Preliminary results from the FIRAS and DIRBE experiments on COBE, Preprint No. 91-05, Proc. The Infrared and Submillimetre Sky After COBE, Les Houches, doi:10.1007/978-94-011-2448-5_13, Mar. 1991.
  • Hauser, M. G., Ed, et al., COBE Diffuse Infrared Background Experiment (DIRBE) Explanatory Supplement, Version 2.3, NASA-GSFC, COBE Publ. No. 98-A, Greenbelt, MD, Jan. 1998.
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