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Table 1 shows the header of the ALLSKY_GC_H1B4 image, the map centered at l = 0°, b = 0°, for HCON 1 and the 100 micron band.

 

Table 1. Sample FITS header
 


SIMPLE  =                    T          / STANDARD FITS FORMAT
BITPIX  =                   32          / 4-BYTE TWOS-COMPL INTEGERS
NAXIS   =                    3          / NUMBER OF AXES
NAXIS1  =                  649          / # SAMPLES PER LINE (FASTEST VARY NDEX)
NAXIS2  =                  325          / # LINES OF DATA IN IMAGE FILE
NAXIS3  =                    1          / # WAVELENGTHS
BSCALE  =         2.499999E+05          / TRUE=TAPE*BSCALE+BZERO
BZERO   =                  0.0          /
BUNIT   = 'JY/SR   '                    / INTENSITY
BLANK   =          -2000000000          / TAPE VALUE FOR EMPTY PIXEL
CRVAL1  =                  0.0          / GALACTIC LONGITUDE AT ORIGIN (DEGREES)
CRPIX1  =                 325.          / SAMPLE AXIS ORIGIN (PIXEL)
CTYPE1  = 'LON--ATF'                    / DECREASES IN VALUE AS SAMPLE INDEX
COMMENT                                   INCREASES  (AITOFF PROJECTION)
CDELT1  =                 -0.5          / COORD VALUE INCREMENT DEG/PIXEL
COMMENT                                   AT ORIGIN ON SAMPLE AXIS
CRVAL2  =                  0.0          / GALACTIC LATITUDE AT ORIGIN (DEGREES)
CRPIX2  =                 163.          / LINE AXIS ORIGIN (PIXEL)
CTYPE2  = 'LAT--ATF'                    / DECREASES IN VALUE AS LINE INDEX
COMMENT                                   INCREASES  (AITOFF PROJECTION)
CDELT2  =                 -0.5          / COORD VALUE INCREMENT DEG/PIXEL
COMMENT                                   AT ORIGIN ON LINE AXIS
CRVAL3  =              1.0E-04          / WAVELENGTH IN METERS
CRPIX3  =                   1.
CTYPE3  = 'LAMBDA  '
CDELT3  =                   0.
DATAMAX =         8.191746E+09          / JY/SR  (TRUE VALUE)
DATAMIN =         5.499999E+06          / JY/SR  (TRUE VALUE)
EPOCH   =                1950.          / EME50
DATE-MAP= '01/11/84'                    / MAP RELEASE DATE (DD/MM/YY)
DATE    = '12/05/86'                    / DATE THIS TAPE WRITTEN (DD/MM/YY)
ORIGIN  = 'JPL-IRAS'                    / INSTITUTION
TELESCOP= 'IRAS    '
INSTRUME= 'ALL SKY '                    / IRAS LOW RES ALL-SKY
OBJECT  = 'CENTER 1'                    / ALL-SKY GALACTIC CENTER / HCON
PROJTYPE= 'AITOFF  '                    / PROJECTION TYPE
COMMENT                                   MINSOP =  29; MAXSOP = 425
COMMENT
COMMENT   PROJECTION FORMULAE:
COMMENT    FORWARD FORMULA; XLON0 IS THE CENTER LONGITUDE OF THE
COMMENT        MAP.  ARC-SINE AND ARC-COSINE FUNCTIONS ARE REQUIRED.
COMMENT     R2D = 45. / ATAN(1.)
COMMENT     PIX = 2.
COMMENT     RHO = ACOS( COS(XLAT) * COS((XLON-XLON0)/2.) )
COMMENT     THETA = ASIN( COS(XLAT) * SIN((XLON-XLON0)/2.) / SIN(RHO) )
COMMENT     F = 2. * PIX * R2D * SIN(RHO/2.)
COMMENT     SAMPLE = -2. * F * SIN(THETA)
COMMENT     XLINE = -F * COS(THETA)
COMMENT     IF(XLAT .LT. 0.)  XLINE = -XLINE
COMMENT
COMMENT    REVERSE FORMULA; XLON0 IS THE CENTER LONGITUDE OF THE MAP.
COMMENT         ARC-SINE AND ARC-COSINE FUNCTIONS NEEDED.
COMMENT     R2D = 45. / ATAN(1.)
COMMENT     PIX = 2.
COMMENT     Y = -XLINE / (PIX * 2. * R2D)
COMMENT     X = -SAMPLE / (PIX * 2. * R2D)
COMMENT     A = SQRT(4.-X*X-4.*Y*Y)
COMMENT     XLAT = R2D * ASIN(A*Y)
COMMENT     XLON = XLON0 + 2. * R2D * ASIN(A*X/(2.*COS(XLAT)))
COMMENT
COMMENT   REFERENCES:
COMMENT    IRAS SDAS SOFTWARE INTERFACE SPECIFICATION(SIS)  #623-94/NO. SF05
COMMENT    ASTRON. ASTROPHYS. SUPPL. SER. 44,(1981) 363-370 (RE:FITS)
COMMENT   RECONCILIATION OF FITS PARMS W/ SIS SF05 PARMS:
COMMENT    NAXIS1 = (ES - SS + 1); NAXIS2 = (EL - SL + 1);
COMMENT    CRPIX1 = (1 - SS);      CRPIX2 = (1 - SL)
END