FITS Headers
DMR_SKYMAP_90A_4YR.FITS
Primary Header
SIMPLE = T / file does conform to FITS standard
BITPIX = 32 / number of bits per data pixel
NAXIS = 0 / number of data axes
EXTEND = T / FITS dataset may contain extensions
COMMENT FITS (Flexible Image Transport System) format defined in Astronomy and
COMMENT Astrophysics Supplement Series v44/p363, v44/p371, v73/p359, v73/p365.
COMMENT Contact the NASA Science Office of Standards and Technology for the
COMMENT FITS Definition document #100 and other FITS information.
DATE = '01/09/95' / FITS file creation date (dd/mm/yy)
COMMENT FITS optional reserved keywords:
DATE-MAP= '18/04/95' / Date when the sky maps were created
ORIGIN = 'CDAC ' / NASA Cosmology Data Analysis Center
TELESCOP= 'COBE ' / Cosmic Background Explorer
INSTRUME= 'DMR ' / Differential Microwave Radiometers
OBJECT = 'ALL-SKY ' /
EQUINOX = 2000.0 /
REFERENC= 'C.L.Bennett, et al., 1995, COBE Preprint 95-04.' /
COMMENT Other related references:
COMMENT 'C.L.Bennett, et al., 1994, APJ, 436, 423.'
COMMENT 'G.F.Smoot, et al., 1992, APJ, 396, L1.'
COMMENT 'C.L.Bennett, et al., 1992, APJ, 396, L7.'
COMMENT 'E.L.Wright, et al., 1992, APJ, 396, L13.'
COMMENT 'A.Kogut, et al., 1992, APJ, 401, 1.'
COMMENT 'C.L.Bennett, et al., 1992, APJ, 391, 466.'
COMMENT 'G.F.Smoot, et al., 1990, APJ, 360, 685.'
COMMENT 'M.A.Janssen and S.Gulkis, 1992, in "The Infrared and Submillimeter
COMMENT Sky after COBE", eds. M.Signore and C.Dupraz (Dordrecht: Kluwer).'
COMMENT COBE/DMR specific keywords:
CHAN_ID = '90A ' / DMR Channel name
COMMENT Channel name is one of 31A, 31B, 53A, 53B, 90A, or 90B
COMMENT The thermodynamic and antenna temperature scales are related by
COMMENT a frequency-dependent factor corresponding to the deviation of the
COMMENT Rayleigh-Jeans law from the Planck function. See DMR calibration
COMMENT paper (Bennett et.al., 1992, APJ, 391, 466) for details.
TEMPTYPE= 'ANTENNA ' / Scale used for temperature fields,
COMMENT / one of 'ANTENNA ' or 'THERMO '
PLNCKCOR= 1.225941 / Thermodynamic temperature =
COMMENT / PLNCKCOR * antenna temperature
FREQ = 9.0E+10 / Frequency in Hz at which data were taken
COMMENT / Also used to define conversion from antenna
COMMENT / to thermodynamic temperature
MAP_TYPE= 'SOLVED ' / Map derives from sparse matrix solution
COORDSYS= 'E ' / Pixelization coordinate system
COMMENT Coordinate system is one of E = Ecliptic, G = Galactic,
COMMENT C = Celestial, i.e. Equatorial, or S = Special
PIXRESOL= 6 / Quad tree pixel resolution
DATE-BEG= '22/12/89' / Data set start date
JSTART = '89356000000000' / Start time YYDDDHHMMSSHHH
DATE-END= '21/12/93' / Data set stop date
JSTOP = '93355235959000' / Stop time YYDDDHHMMSSHHH
COMMENT DATE-BEG and DATE-END give the date during which
COMMENT the earliest and the latest data used in this product
COMMENT were obtained.
COMMENT JSTART and JSTOP delimit in a form expected by COBE software
COMMENT the interval of time during which the data used
COMMENT in this product were obtained.
BASELINE= 'MEAN ' / Baseline used
RMS_NOML= 40.307106 / Nominal rms noise level (mK in 0.5 sec)
RMS_FLGT= 39.097415 / Flight rms noise level (from Chi-squared)
CHI_SQ = 0.94087701 / Chi-squared value per degree of freedom
B_DOT_M = 0.00008795 / B*M value per degree of freedom
S_DOT_S = 0.94096496 / S*S value per degree of freedom
COMMENT Chi-squared is an approximation to SUM (S - T)**2/RMS_NOML**2
COMMENT where S is the calibrated, corrected measurement,
COMMENT T is the predicted measurement based on sky temperature pattern
COMMENT and couplings to systematic error model functions,
COMMENT and RMS_NOML is the nominal RMS.
COMMENT See the references, especially Janssen and Gulkis, for details.
COMMENT Analogously, S*S is SUM S**2/RMS_NOML**2 and B*M is the dot product
COMMENT between the measurement vector and the solution skymap.
COMMENT CHI_SQ = S*S - B*M
COMMENT RMS_FLGT = RMS_NOML*SQRT(CHI_SQ)
D_O_F = 218386196 / Total degree of freedom
TOT_OBS = 218398620 / Total number of observations
COMMENT / i.e. number of data points used
COMMENT / in calculation of this map
SUM_OBS = 436797240 / Sum of number of observations field
COMMENT / for each pixel in this map
COMMENT For SOLVED maps SUM_OBS = 2*TOT_OBS because each observation
COMMENT is attributed to two pixels. For COADDED maps there is no
COMMENT direct relation between the two.
ECLIPSE = T / If "T", eclipse data are included
COR_MAGS= T / If "T", magnetic susceptibility corrected
COR_MEMO= T / If "T", LIA memory corrected
COR_ECLI= T / If "T", eclipse effect corrected
COR_EART= F / If "T", Earth limb corrected
COR_MOON= T / If "T", Moon corrected
COR_MARS= T / If "T", Mars corrected
COR_JUPI= T / If "T", Jupiter corrected
COR_SATU= T / If "T", Saturn corrected
VEL_SUN = T / If "T", Sun velocity corrected
VEL_EART= T / If "T", Earth velocity corrected
VEL_COBE= T / If "T", satellite velocity corrected
COMMENT
COMMENT
COMMENT The following vector defines the dipole which has been removed
COMMENT from this dataset ("sun velocity correction"). The purpose of
COMMENT this correction is to minimize the gradient over a pixel due
COMMENT to the dipole; this vector is neither a definitive DMR value
COMMENT for the dipole nor the best fit dipole derived from this dataset.
COMMENT To restore the dipole to the SIGNAL for each pixel add the dot
COMMENT product of this vector with the pointing for the pixel.
COMMENT The vector is in mK antenna temperature in Ecliptic coordinates.
DIP_MAG = 2.737677 / Magnitude in mK antenna
COMMENT / of value used to remove dipole
DIP_ELON= 171.8793 / Ecliptic longitude in degrees
COMMENT / of value used to remove dipole
DIP_ELAT= -11.67802 / Ecliptic latitude in degrees
COMMENT / of value used to remove dipole
END
DMR_SKYMAP
XTENSION= 'BINTABLE' / Extension type is Binary Table
BITPIX = 8 / Binary data
NAXIS = 2 / Data are in a table
NAXIS1 = 40 / Number of 8 bit bytes in each row
NAXIS2 = 6144 / Number of rows
PCOUNT = 0 / Number of bytes of data following table
GCOUNT = 1 / Group count (always 1 for bintable extensions)
TFIELDS = 10 / Number of fields (columns) in the table
COMMENT DMR Project Data Set FITS Skymap
COMMENT
EXTNAME = 'DMR_SKYMAP' / name of this binary table extension
COMMENT
COMMENT Pixel number
TFORM1 = '1J ' / data format of the field: 4-byte INTEGER
TTYPE1 = 'PIXEL ' / entire fieldname = PIXEL
TUNIT1 = ' ' /
COMMENT
COMMENT Antenna temperature for this pixel in mK
TFORM2 = '1E ' / data format of the field: 4-byte REAL
TTYPE2 = 'SIGNAL ' / entire fieldname = SIGNAL
TUNIT2 = 'mK ' / physical unit of field
COMMENT
COMMENT Number of observations for this pixel
TFORM3 = '1J ' / data format of the field: 4-byte INTEGER
TTYPE3 = 'N_OBS ' / entire fieldname = N_OBS
TUNIT3 = ' ' /
COMMENT
COMMENT Estimated pixel uncertainty
COMMENT as RMS_FLGT/SQRT(N_OBS)
TFORM4 = '1E ' / data format of the field: 4-byte REAL
TTYPE4 = 'SERROR ' / entire fieldname = SERROR
TUNIT4 = 'mK ' / physical unit of field
COMMENT
COMMENT The following geometric quantities refer to the nominal
COMMENT pixel center, not the average of actual lines of sight.
COMMENT
COMMENT Ecliptic longitude of pixel center in degrees (0, 360)
TFORM5 = '1E ' / data format of the field: 4-byte REAL
TTYPE5 = 'ECLON ' / entire fieldname = ECLON
TUNIT5 = 'DEGREES ' / physical unit of field
COMMENT
COMMENT Ecliptic latitude of pixel center in degrees (-90, 90)
TFORM6 = '1E ' / data format of the field: 4-byte REAL
TTYPE6 = 'ECLAT ' / entire fieldname = ECLAT
TUNIT6 = 'DEGREES ' / physical unit of field
COMMENT
COMMENT Galactic longitude of pixel center in degrees (0, 360)
TFORM7 = '1E ' / data format of the field: 4-byte REAL
TTYPE7 = 'GALON ' / entire fieldname = GALON
TUNIT7 = 'DEGREES ' / physical unit of field
COMMENT
COMMENT Galactic latitude of pixel center in degrees (-90, 90)
TFORM8 = '1E ' / data format of the field: 4-byte REAL
TTYPE8 = 'GALAT ' / entire fieldname = GALAT
TUNIT8 = 'DEGREES ' / physical unit of field
COMMENT
COMMENT Right ascension of pixel center in degrees (0, 360)
TFORM9 = '1E ' / data format of the field: 4-byte REAL
TTYPE9 = 'RA ' / entire fieldname = RA
TUNIT9 = 'DEGREES ' / physical unit of field
COMMENT
COMMENT Declination of pixel center in degrees (-90, 90)
TFORM10 = '1E ' / data format of the field: 4-byte REAL
TTYPE10 = 'DEC ' / entire fieldname = DEC
TUNIT10 = 'DEGREES ' / physical unit of field
COMMENT
END
