FITS Headers
DIRBE_BEAM04_P3B.FITS
Primary Header
SIMPLE = T / file does conform to FITS standard BITPIX = -32 / REAL*4 data NAXIS = 3 / number of data axes NAXIS1 = 225 / in-scan axis NAXIS2 = 181 / cross-scan axis NAXIS3 = 3 / time-period axis DATE-MAP= '30/06/95' / Date of original data file creation (dd/mm/yy) DATE = '11/02/97' / FITS file creation date (dd/mm/yy) ORIGIN = 'CDAC' / Cosmology Data Analysis Center TELESCOP= 'COBE' / Cosmic Background Explorer satellite INSTRUME= 'DIRBE' / COBE instrument [DIRBE, DMR, FIRAS] OBJECT = 'BEAM' / DIRBE beam profile map REFERENC= 'COBE/DIRBE Explanatory Supplement,' / REFERENC= 'ed. M.G. Hauser, T. Kelsall, D. Leisawitz, and J. Weiland,' / REFERENC= 'COBE Ref. Pub. No. 97-A (Greenbelt,MD: NASA/GSFC),' / REFERENC= 'available in electronic form from the NSSDC.' / COMMENT COMMENT COBE specific keywords DATE-BEG= '11/12/89' / date of initial data represented (dd/mm/yy) DATE-END= '21/09/90' / date of final data represented (dd/mm/yy) COMMENT COMMENT DIRBE specific keywords PRODUCT = 'BEAM04' / DIRBE Band 4 beam profile VERSION = 'Pass 3B' / Version of Data Reduction Software WAVE4 = '4.9 microns' / nominal wavelength of Band 4 SOLELONG= 'ALL' / all available solar elongations used APPVEC = 'COMBINED' / data having different approach vectors COMMENT / are combined during processing COMMENT COMMENT COMMENT ------------------------------------------------------------------- COMMENT ******************************************************************* COMMENT Beam Profile -- DIRBE Band 4. COMMENT This is an effective beam profile, which measures the COMMENT relative response of the DIRBE to a point source, including COMMENT the effects of sky-scanning and data-sampling rates. COMMENT Beam profiles are represented as two-dimensional COMMENT arrays which give the beam response as a COMMENT function of in-scan and cross-scan position. COMMENT In-scan position is defined as positive COMMENT toward the scan direction, and cross-scan position is COMMENT defined as positive toward the spacecraft spin-axis. COMMENT The origin (0,0) corresponds to the nominal boresight COMMENT position as defined from the attitude solution. COMMENT COMMENT Beam profiles for Band 4 were noted to be COMMENT slightly time-dependent. Therefore, 3 beam profiles are COMMENT recorded here, covering the following time intervals (YYDDD): COMMENT beam #1: 89345 - 90175 (inclusive) COMMENT beam #2: 90176 - 90231 (inclusive) COMMENT beam #3: 90232 - 90264 (inclusive) COMMENT COMMENT Beam #1 is normalized to a value of 1.0 at the COMMENT location of peak response. Beams #2 and #3 COMMENT are normalized such that the beam profile solid angle COMMENT is constant during the cold mission, using the solid angle COMMENT found for Beam #1. The peak response of beams #2 and #3 COMMENT differs from unity by at most 1.7%. COMMENT COMMENT The beam solid angle for Band 4 used in the Pass3B data COMMENT processing is 1.463 e-04 sr. COMMENT ******************************************************************* COMMENT ------------------------------------------------------------------- CRVAL1 = 0.000000 / Value at origin (arcmin) CRPIX1 = 113 / position of origin CTYPE1 = 'INSCAN' / in-scan coordinate; range +- 42 arcmin CDELT1 = 0.375000 / in-scan sampling increment, arcmin per pixel COMMENT ------------------------------------------------------------------- CRVAL2 = 0.000000 / Value at origin (arcmin) CRPIX2 = 91 / position of origin CTYPE2 = 'XSCAN' / x-scan coordinate; range +- 36 arcmin CDELT2 = 0.400000 / x-scan sampling increment, arcmin per pixel COMMENT ------------------------------------------------------------------- CRVAL3 = 1 / CRPIX3 = 1 / CTYPE3 = 'BEAM-NO' / beam number; range 1-3 CDELT3 = 1 / COMMENT ------------------------------------------------------------------- END
