ABOUT LAMBDA

COBE

Cosmic Background Explorer/FIRAS

Product Name
FIRAS instantaneous Beam Profile
Mission
COBE/FIRAS

Description

A representative instantaneous FIRAS beam radial profile was determined using multiple on-orbit observations of the Moon. In practice, the finite dwell time of each FIRAS interferogram results in an effective beam which is elongated in the scan direction. The in-scan elongation is not incorporated in the tabulated instantaneous beam.

For an example of calibration comparison between FIRAS and another instrument, including treatment of the beam, see Fixsen et. al (1997).

References:

FIRAS Explanatory Supplement, Chapter 7 "Errors and Uncertainty Estimation"
Fixsen, D.J., et. al, 1997 ApJ 490,482 "Comparison of the COBE FIRAS and DIRBE Calibrations"

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A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Alan P. Smale
LAMBDA Director: Dr. Eric R. Switzer
NASA Official: Dr. Eric R. Switzer
Web Curator: Mr. Michael R. Greason