FITS Headers
DIRBE_BEAM1A_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 = 'BEAM1A' / DIRBE Band 1A beam profile VERSION = 'Pass 3B' / Version of Data Reduction Software WAVE1 = '1.25 microns' / nominal wavelength of Band 1 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 1A. 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 1A 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 less than 1%. COMMENT COMMENT The beam solid angle for Band 1A used in the Pass3B data COMMENT processing is 1.198 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
