Appendix X.3 Sample FITS Headers

IRAS Explanatory Supplement
X. The Formats of the IRAS Catalogs and Atlases
Appendix X.3 Sample FITS Headers


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Header for Sky Plate Intensity

SIMPLE =                        T    / STANDARD FITS FORMAT
BITPIX =                       32    / 4 BYTE TWOS COMPL INTEGER
NAXIS =                         3    / NUMBER OF AXES
NAXIS1 =                       nn    / # SAMPLES PER LINE (FASTEST
VARY INDEX)
NAXIS2 =                       mm    / # LINES OF DATA IN IMAGE
FILE
NAXIS3 =                        1    / # WAVELENGTHS
BSCALE =             S.ssssssE-ee    / TRUE=TAPE*SCALE+BZERO
BZERO =                       0.0    /
BUNIT =       'JY/SR'                / INTENSITY
BLANK =               -2000000000    / TAPE VALUE FOR EMPTY PIXEL
CRVAL1 =                    DD.dd    / RA AT ORIGIN (DEGREES)
CRPIX1 =                      xxx.    / SAMPLE AXIS ORIGIN (PIXEL)
CTYPE1 =      'RA--TAN'               / DECREASES IN VALUE AS
SAMPLE INDEX
COMMENT                             INCREASES (GNOMONIC PROJECTION
CDELT1 =             -3.333333E-02   / COORD VALUE INCREMENT DEG/PIXEL
COMMENT                                 AT ORIGIN ON SAMPLE AXIS
CRVAL2 =                    DD.dd    / DEC AT ORIGIN (DEGREES)
CRPIX =                      yyy.    / LINE AXIS ORIGIN (PIXEL)
CTYPE2 =     'DEC--TAN'              / DECREASES IN VALUE AS LINE
INDEX
COMMENT                                INCREASES (GNOMONIC PRJECTION)
CDELTA2 =             -3.333333E-02   / COORD VALUE INCREMENT
DEG/PIXEL
COMMENT                                AT ORIGIN ON LINE AXIS
CRVAL3 =                     zzzE-6   / WAVELENGTH IN METERS
CRPIX3 =                         1.
CTYPE3 =    'LAMBDA '
CDELT3 =                         0.
DATAMIX =           D.ddddddE ee      / JY/SR (TRUE VALUE)
DATAMIN =           D.ddddddE ee      / JY/SR (TRUE VALUE)
EPOCH =                      1950.    / EME.50
DATE-MAP =    '01/11/84'              / MAP RELEASE DATE
DATE =        'DD/MM/YY'              / DATE THIS TAPE WRITTEN
ORIGIN =      'JPL-IRAS'              / INSTITUTION
TELESCOP =    'IRAS'
INSTRUME =    'SKYPLATE'              / IRAS SKY PLATE
OBJECT =      'PLnnn Hn'              / PLATE NUMBER/ HCON
PROJTYE =     'GNOMONIC'              / PROJECTION TYPE
COMMENT                                MINSOP = MMM; MAXSOP =
NNN
COMMENT                                LOGTAG = VSFLOG(7.6)
COMMENT                                GEOMTAG = GEOM(7.5)
COMMENT
COMMENT      PROJECTION FORMULAE:
COMMENT         FORWARD FORMULA; RA0 AND DEC0 ARE THE PLATE CENTER
COMMENT      R2D = 45./ ATAN(1.)
COMMENT      PIX = 30.
COMMENT      A = COS(DEC) * COS(RA0 - RA)
COMMENT      F = PIX * R2D/(SIN(DEC0) * SIN(DEC) + A * COS(DEC0))
COMMENT      SAMPLE = -F * COS(DEC) * SIN(RA-RA0)
COMMENT      XLINE = -F * (COS(DEC0) * SIN(DEC) - A * SIN(DEC0))
COMMENT
COMMENT        INVERSE FORMULA; REQUIRES ARCSINE
COMMENT      X = SAMPLE/ (PIX * R2D)
COMMENT      Y = LINE/ (PIX * R2D)
COMMENT      DELTA = ATAN(SQRT(X*X + Y*Y))
COMMENT      BETA = ATAN2(-X,Y)
COMMENT      DEC = ASIN(SIN(DEC0)*COS(DELTA)-COS(DEC0)*SIN(DELTA)*COS(BETA))
COMMENT      XX = SIN(DEC0)*SIN(DELTA)*COS(BETA)+COS(DEC0)*COS(DELTA)
COMMENT      YY = SIN(DELTA)*SIN(BETA)
COMMENT      RA = RA0 + ATAN2(YY,XX)
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

Header for 16.5° Image Weight

SIMPLE =                          T    / STANDARD FITS FORMAT
BITPIX =                         16    / 2 BYTE TWOS COMPL INTEGER
NAXIS =                           3    / NUMBER Of AXES
NAXIS1 =                         nn    / # SAMPLES PER LINE (FASTEST
VARY INDEX
NAXIS2 =                         mm    / # LINES OF DATA IN IMAGE
FILE
NAXIS3 =                          1    / # WAVELENGTHS
BSCALE =                         1.    / TRUE=TAPE*SCALE+BZERO
BZERO =                         0.0    /
BUNIT =       '       '                / STATISTICAL WEIGHT
BLANK =                           0    / TAPE VALUE FOR EMPTY
PIXEL
CRVAL1 =                      DD.dd    / RA AT ORIGIN (DEGREES)
CRPIX1 =                       xxx.    / SAMPLE AXIS ORIGIN (PIXEL)
CTYPE1 =       'RA--TAN'               / DECREASES IN VALUE AS
SAMPLE INDEX
COMMENT                                  INCREASES (GNOMONIC PROJECTION)
CDELT1 0=             -3.333333E-02    / COORD VALUE INCREMENT
DEG/PIXEL
COMMENT                                  AT ORIGIN ON SAMPLE AXIS
CRVAL2 =                      DD.dd    / DEC AT ORIGIN (DEGREES)
CRPIX2 =                        ny.    / LINE AXIS ORIGIN (PIXEL)
CTYPE2 =       'DEC--TAN'              / DECREASES IN VALUE AS
LINE INDEX
COMMENT                                 INCREASES (GNOMONIC PROJECTION)
CDELTA2 =             -3.333333E-02    / COORD VALUE INCREMENT
DEG/PIXEL
COMMENT                                   AT ORIGIN ON LINE AXIS
CRVAL3 =                    z.zzE-6    / WAVELENGTH IN METERS
CRPIX3 =                          1.
CTYPE3 =    'LAMBDA '
CDELT3 =                          0.
DATAMAX =                D.ddddddE ee  / DIMENSIONLESS
DATAMIN =                D.ddddddE ee  / DIMENSIONLESS
EPOCH =                        1950.   / EME50O
DATE-MAP =     '01/11/84'              / MAP RELEASE DATE
DATE =         'DD/MM/YY'              / DATE THIS TAPE WRITTEN
ORIGIN =       'JPL-IRAS'              / INSTITUTION
TELESCOPE =    'IRAS    '
INSTRUME =     'SKYPLATE'              / IRAS SKY PLATE
OBJECT =       'PLnnn Hn'              / PLATE NUMBER/ HCON
PROJTYPE =     'GNOMONIC'              / PROJECTION TYPE
COMMENT                                  MINSOP = MMM; MAXSOP = NN
COMMENT                                  LOGTAG = VSFLOG(7.8)
COMMENT                                  GEOMTAG = GEOM (7.5)
COMMENT
COMMENT         PROJECTION FORMULAE:
COMMENT           FORWARD FORMULA; RAO AND DEC0 ARE THE PLATE
CENTER
COMMENT         R2D = 45. / ATAN(l.)
COMMENT         PIX = 30.
COMMENT         A = COS(DEC) * COS(RA0 - RA)
COMMENT         F = PIX * R2D/ (SM(DEC0) * SIN(DEC) + A * COS(DEC0))
COMMENT         SAMPLE = -F * COS(DEC) * SIN(RA-RA0)
COMMENT         XLINE = -F * (COS(DEC0) - SIN(DEC), A * SIN(DEC0))
COMMENT
COMMENT            INVERSE FORMULA; REQUIRES ARCSINE
COMMENT         X = SAMPLE/ (PIX * R2D)
COMMENT         Y = LINE/ (PIX * R2D)
COMMENT         DELTA = ATAN(SQRT(X*X + Y*Y))
COMMENT      BETA = ATAN2(-X,Y)
COMMENT      DEC = ASIN(SIN(DEC0)*COS(DELTA)-COS(DEC0)*SIN(DELTA)*COS(BETA))
COMMENT      XX = SIN(DEC0)*SIN(DELTA)*COS(BETA)+COS(DEC0)*COS(DELTA)
COMMENT      YY = SIN(DELTA)*SIN(BETA)
COMMENT      RA = RA0 + ATAN2(YY,XX)
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 SFO5 PARMS:
COMMENT      NAXIS1 = (ES - SS + 1); NAXIS2 = (EL - SL + 1);
COMMENT      CRPIX1 = (1 - SS);    CRPIX2 = (1 - SL)
END

Header for Galactic Plane Fields

SIMPLE =                          T    / STAMDARD FITS FORMAT
BITPIX =                         32    / 4 BYTE TWOS COMPL INTEGER
NAXIS =                           3    / NUMBER OF AXES 
NAXIS1 =                         nn    / # SAMPLES PER LINE (FASTEST
VARY INDEX)
NAXIS2 =                         mm    / # LINES OF DATA IN IMAGE
FILE
NAXIS3 =                          1    / # WAVELENGTHS
BSCALE =                 S.SSSSSSEee   / TRUE=TAPE*SCALE+BZERO
BZERO =                         0.0    /
BUNIT =        'JY/SR'                 / INTENSITY
BLANK =                - 2000000000    / TAPE VALUE FOR EMPTY
PIXEL
CRVAL1 =                      DD.dd    / GALACTIC LONGITUDE AT
ORIGIN (DEGREES)
CRPIX1 =                       xxx.    / SAMPLE AXIS ORIGIN (PIXEL)
CTYPE1 =       'GLON  '                / DECREASES IN VALUE AS
SAMPLE INDEX
COMMENT                                  INCREASES  (LAMBERT EQUIVALENT)
COMMENT                                  CYLINDRICAL PROJECTION)
CDELT1 =               -3.333333E-02   / COORD VALUE INCREMENT
DEG/PIXEL
COMMENT                                 AT ORIGIN ON SAMPLE AXIS
CRVAL2 =                         0.0    / GALACTIC LATITUDE AT
ORIGIN (DEGREES)
CRPIX2 =                        yyy.    / LINE AXIS ORIGIN (PIXEL)
CTYPE2 =       'GLAT-SIN'               / DECREASES IN VALUE AS
LINE INDEX
COMMENT                                   INCREASES  (LAMBERT
EQUIVALENT
COMMENT                                   CYLINDRICAL PROJECTION
CDELTA2 =              -3.333333E-02    / COORD VALUE INCREMENT
DEG/PIXEL
COMMENT                                   AT ORIGIN ON LINE AXIS
CRVAL3 =                     zzzE-6     / WAVELENGTH IN METERS
CRPIX3 =                         1.
CTYPE3 =       'LAMBDA '
CDELT3 =                         0.
DATAMAX =               D.ddddddE ee    / JY/SR (TRUE VALUE)
DATAMIN =               D.ddddddE ee    / JY/SR (TRUE VALUE)
EPOCH =                        1950.    / EME5O
DATE-MAP =      '01/11/84'              / MAP RELEASE DATE
DATE =          'DD/MM/YY'              / DATE THIS TAPE WRITTEN
ORIGIN =        'JPL-IRAS'              / INSTITUTION
TELESCOP =      'IRAS  '
INSTRUME =      'GALPLANE'              / IRAS GALACTIC PLANE
OBJECT =        'GPLnn Hn'              / GALACTIC PLANE PLATE
NUMBER/ HCON
PROJTYPE =      'LAMBECYL'              / PROJECTION TYPE
COMMENT
COMMENT          PROJECTION FORMULAE:
COMMENT            FORWARD FORMULA; XLONG IS THE LONGITUDE OF
PLATE CENTER
COMMENT          R2D = 45./ ATAN(1.)
COMMENT          PIX = 30.
COMMENT          XLINE = -SIN(XLAT) * PIX * R2D
COMMENT          SAMPLE = (XLON - XLON0) * PIX
COMMENT
COMMENT            INVERSE FORMULA; ARCSINE IS REQUIRED
COMMENT          XLON = XLON0 - SAMPLE / PIX
COMMENT          XLAT = -ASIN(XLINE / (PIX * R2D))
COMMENT          REFERENCES:
COMMENT          IRAS SDAS SOFTWARE INTERFACE SPECIFICATION(SIS) #623-94/N0. SFO5
COMMENT          ASTRON. ASTROPHYS. SUPPL. SER. 44,(1981) 363-370 (RE:FITS)
COMMENT         RECONCILIATION OF FITS PARMS W/ SIS SFO5 PARMS:
COMMENT         NAXIS1 = (ES - SS + 1); NAXIS2 = (EL - SL + 1);
COMMENT         CRPIX1 = (1 - SS)    CRPIX2 = ( 1 - SL)

Header for Low-Resolution All-Sky Image (Galactic Center)

SIMPLE =                      T   / STANDARD FITS FORMAT
BITPIX =                     32   / 4 BYTE TWOS COMPL INTEGERS
NAXIS =                       3   / NUMBER OF AXES
NAXIS1 =                     nn   / # SAMPLES PER LINE (FASTEST
VARY NDEX)
NAXIS2 =                     mm   / # LINES OE DATA IN IMAGE FILE
NAXIS3 =                      1   / # WAVELENGTHS
BSCALE =           S.ssssssE-ee   / TRUE=TAPE*SCALE+BZERO
BZERO =                     0.0   /
BUNIT =     'JY/SR'               / INTENSITY
BLANK =             -2000000000   / TAPE VALUE FOR EMPTY PIXEL
CRVAL1l =                 DD.dd   / GALACTIC LONGITUDE AT ORIGIN
(DEGREES)
CRPIX1 =                    xxx.   / SAMPLE AXIS ORIGIN (PIXEL)
CTYPE1 =     'LON-AFT'             / DECREASES IN VALUE AS SAMPLE
INDEX
COMMENT                              INCREASES (AITOFF PROJECTION)
CDELTA1 =    'LON-AFT '      0.5   / COORD VALUE INCREMENT DEG/PIXEL
COMMENT                               AT ORIGIN ON SAMPLE AXIS
CRVAL2 =                     0.0   / GALACTIC LATITUDE AT ORIGIN
(DEGREES)
CRPIX2 =                    yyy.   / LINE AXIS ORIGIN (PIXEL)
CTYPE2 =      'LAT-ATF'            / DECREASES IN VALUE AS LINE
INDEX
COMMENT                              INCREASES (AITOFF PROJECTION)
CDELT2 =      'LAT-AFT'     -0.5   / COORD VALUE INCREMENT DEG/PIXEL
COMMENT                               AT ORIGIN ON LINE AXIS
CRVAL3 =                  z.zzE-6   / WAVELENGTH IN METERS
CRPIX3 =                       1.
CTYPE3 =       'LAMBDA '
CDELT3 =                       0.
DATAMAX =            D.ddddddE ee   / JY/SR (TRUE VALUE)
DATAMIN =            D.ddddddE ee   / JY/SR (TRUE VALUE)
EPOCH =                     1950.   / EME5O
DATE-MAP =   'O1/11/84'             / MAP RELEASE DATE
DATE =       'DD/MM/YY'             / DATE THIS TAPE WRITTEN
ORIGIN =     'JPL-IRAS'             / INSTITUTION
INSTRUME =   'ALL SKY'              / IRAS LOW RES ALL-SKY
OBJECT =     'CENTER n'             / ALLLSKY GALACTIC CENTER/
HCON
PROJTYPE =   'AITOFF '              / PROJECTION TYPE
COMMENT                               MINSOP = MMM; MAXSOP = NNN
COMMENT
COMMENT       PROJECTION FORMULAE:
COMMENT       FORWARD FORMULA; XLONO 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       THEATA = 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) #623-94N0. SF05
COMMENT       ASTRON. ASTROPHYS. SUPPL. SER. 44,(1981) 363-370 (RE:FITS)
COMMENT       RECONCILIATION OF FITS PARMS W/ SIS Ff05 PARMS:
COMMENT       NAXIS1 = (ES - SS + 1); NAXIS2 = (EJ - SL + 1);
COMMENT       CRPIX1 = (1 - SS);    CRPIX2 = (1 - SL)
END

Header for Low-Resolution All-Sky Intensity Galactic Antit-Center

SIMPLE =                      T   / STANDARD FITS FORMAT
BITPIX =                     32   / 4 BYTE TWOS COMPL INTEGER
NAXIS =                       3   / NUMBER OF AXES
NAXIS1 =                     nn   / # SAMPLES PER LINE (FASTEST
VARY NDEX
NAXIS2 =                     mm   / # LINES Of DATA IN IMAGE FILE
NAXIS3 =                      1   / # WAVELENGTHS
BSCALE =           S.ssssssE-ee   / TRUE=TAPE*SCALE+BZERO
BZERO =                     0.0   /
BUNIT =    'JY/SR'                / INTENSITY
BLANK =             -2000000000   / TAPE VALUE FOR EMPTY PIXEL
CRVAL1 =                  150.0   / GALACTIC LONGITUDE AT ORIGIN
(DEGREES)
CRPIX1 =                   xxx.   / SAMPLE AXIS ORIGIN (PIXEL)
CTYPE1 =   'LON-ATF'              / DECREASES IN VALUE AS SAMPLE
INDEX
COMMENT                             INCREASES (AITOF PROJECTION)
CDELT1 =                    -0.5  / COORD VALUE INCREMENT DEG/PIXEL
COMMENT                             AT ORIGIN ON SAMPLE AXIS
CRVAL2 =                     0.0  / GALACTIC LATITUDE AT ORIGIN
(DEGREES)
CRPIX2 =                    yyy.  / LINE AXIS ORIGIN (PIXEL)
CTYPE2 =    'LAT-ATF'             / DECREASES IN VALUE AS LINE
INDEX
COMMENT                             INCREASES (AITOFF PROJECTION)
CDELLT2 =                   -0.5  / COORD VALUE INCREMENT DEG/PIXEL
COMMENT                             AT ORIGIN ON LINE AXIS
CRVAL3 =                z.zzE-6   / WAVELENGTH IN METERS
CRPIX3 =                      1.
CTYPE3 =     'LAMBDA '
CDELT3 =                      0.
DATAMAX =          D.ddddddE ee   / JY/SR (TRUE VALUE)
DATAMIN =          D.ddddddE ee   / JY/SR (TRUE VALUE)
EPOCH =                    1950.  / EME50
DATE-MAP =    '01/11/84'          / MAP RELEASE DATE
DATE =        'DD/MM/YY'          / DATE THISS TAPE WRITTEN
ORIGIN =      'JPL-IRAS'          / INSTITUTION
TELESCOP =    'IRAS   '
INSTRUME =    'ALL SKY'           / IRAS LOW RES ALL-SKY
OBJECT =      'ACENTERN'          / ALL-SKY GALACTIC ANTI-CENTER/
HCON
PROJTYPE =    'AITOFF'            / PROJECTION TYPE
COMMENT                             MINSOP = MMM; MAXSOP = NNN
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 FORMULAA; XLON0 IS THE CENTER LONGITUDE OF THE MAP.
COMMENT        ARC-SINE AND ARC-COSINE FUCTIONS NEEDED.
COMMENT    R2D = 45./ ATAN(1.)
COMMENT    PIX = 2.
COMMENT    Y = -XLINE/ (PIX * 2. * R2D)
COMMENT    X = -SAMPLE/ (P(X * 2. * R2D)
COMMENT    A = SQRT(4.-X*X-4.*YY)
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 SFO5 PARMS:
COMMENT    NAXIS1 = (ES - SS + 1); NAXIS2 = (EL - SL + 1);
COMMENT    CRPIXl = (1 - SS);     CRPIX2 = (1 - SL)
END

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