Cosmic Background Explorer/DIRBE

Product Name
Beam Characteristics


A single file which tabulates Beam Centroids and Solid Angles for all 16 DIRBE detectors for the duration of the Cryogenic Mission (11-Dec-1989 to 21-Sep-1990). Centroids are expressed as (in-scan, cross-scan) offsets from the origin (0,0) defined by the attitude solution. The centroids for bands 1-4 are time dependent, and have been tabulated for three time intervals. The centroids were used as offsets from the position of the line-of-sight given by the attitude solution to determine the sky pixel in which each DIRBE data sample was placed. Beam solid angles were computed based on the beam response over an area +/- 42.2 arcminutes in-scan and +/-36.2 arcmin cross-scan.

See the COBE/DIRBE Explanatory Supplement and BEAM_PROFILE data product for further explanation of beam coordinates and normalization of the beam profile. See the description of the CIO data product in Chapter 5 of the Explanatory Supplement for an explanation of how to use these offsets in the construction of resolution 15 coordinates.

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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