ABOUT LAMBDA

FITS Headers

DIRBE_BEAM1B_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 = 'BEAM1B'             / DIRBE Band 1B 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 1B.                                       
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 1B 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 1B used in the Pass3B data             
COMMENT    processing is  1.174 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                                                                             

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