WMAP Beam Map FITS Header Information

A beam map is stored in the primary header/data unit (HDU) of its FITS file as a three dimensional array, allowing four maps to be stored in the HDU through the use of the third dimension. These maps are:

1. The beam map for the A side, in mK (antenna temperature).
2. The statistical error of each bin on the A side map, in mK (antenna temperature).
3. The beam map for the B side, in mK (antenna temperature).
4. The statistical error of each bin on the B side map, in mK (antenna temperature).

Primary Header

SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                  -32 / number of bits per data pixel
NAXIS   =                    3 / number of data axes
NAXIS1  =                  600 / in-scan axis
NAXIS2  =                  600 / cross-scan axis
NAXIS3  =                    4 / array id index
EXTEND  =                    T / FITS dataset may contain extensions
COMMENT   FITS (Flexible Image Transport System) format is defined in 'Astronomy
COMMENT   and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H
DATE    = '2009-12-17T00:00:00' /file creation date (YYYY-MM-DDThh:mm:ss UT)
TELESCOP= 'WMAP     '          / Wilkinson Microwave Anisotropy Probe
OBJECT  = 'JUPITER '           / Beam maps of Jupiter
COMMENT   This file contains hybrid beam maps constructed from data supplemented
COMMENT   with model predictions for the low signal-to-noise pedestals.  Data
COMMENT   consist of sightings of Jupiter during the first 7 years of WMAP
COMMENT   observations.  Model predictions were substituted for data at the
COMMENT   3, 4, 6, 7 and 10 dBi levels of K,Ka,Q,V and W, respectively.
COMMENT   The hybrid beams provided in this file are for the
COMMENT   differencing assembly indicated by the DA keyword. The contents of the
COMMENT   four 600x600 arrays are identified as follows from the CTYPE3 value:
COMMENT   1 = beam map for Side A, in mK, antenna temperature
COMMENT   2 = statistical noise for each side A pixel, in mK, antenna temp.
COMMENT       Model points are assigned 100% error.
COMMENT   3 = beam map for Side B, in mK, antenna temperature
COMMENT   4 = statistical noise for each side B pixel, in mK, antenna temp.
COMMENT       Model points are assigned 100% error.
COMMENT   Beam data are provided out to roughly 7.0, 5.5, 5.0, 4.0 and 3.5
COMMENT   degrees from beam center for K, Ka, Q, V and W bands respectively.
COMMENT   Pixels with no coverage have values of zero.  Beam response has  not
COMMENT   been corrected for the input transmission imbalance (A/B asymmetry).
COMMENT   Origin of the focal plane coordinates [Xbeam,Ybeam] is the primary
COMMENT   optic axis for either the A or B side; the individual antenna feeds
COMMENT   are clustered about this axis.
REFERENC= 'WMAP Explanatory Supplement: http://lambda.gsfc.nasa.gov/
RELEASE = 'DR4     '           / WMAP Release
VERSION = 'PASS 4  '           / Internal WMAP Version
STARTGMT= '20012690000000000000' / Start time of TOD used
ENDGMT  = '20082212359000000000' / End time of TOD used
DA      = 'Q1      '           / Differencing Assembly
STOKES  = 'Intensity'          / i, q, or u
COMMENT
CRVAL1  =         -11.9800000  / Value at first pixel (degrees)
CRPIX1  =                   1  / position of first pixel
CTYPE1  = 'Xbeam'              / in-scan coordinate; range +-12 degrees
CDELT1  =           0.0400000  / in-scan bin increment, degree per pixel
COMMENT
CRVAL2  =         -11.9800000  / Value at first pixel (degrees)
CRPIX2  =                   1  / position of first pixel
CTYPE2  = 'Ybeam'              / cross-scan coordinate, range +-12 degrees
CDELT2  =           0.0400000  / x-scan bin increment, degree per pixel
COMMENT
CRVAL3  =                   1  /
CRPIX3  =                   1  /
CTYPE3  = 'Array id'           / identifier specifying contents of 4 map arrays
CDELT3  =                   1  /
COMMENT
END

More information concerning the contents of this file is available.