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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