Data Extension

XTENSION= 'BINTABLE'           / binary table extension
BITPIX  =                    8 / 8-bit bytes
NAXIS   =                    2 / 2-dimensional binary table
NAXIS1  =                    8 / width of table in bytes
NAXIS2  =                 1024 / number of rows in table
PCOUNT  =                    0 / size of special data area
GCOUNT  =                    1 / one data group (required keyword)
TFIELDS =                    3 / number of fields in each row
TTYPE1  = 'CHANNEL '           / label for field   1
TFORM1  = 'I       '           / data format of the field: 2-byte INTEGER
TTYPE2  = 'COUNTS  '           / label for field   2
TFORM2  = 'J       '           / data format of the field: 4-byte INTEGER
TUNIT2  = 'count   '           / physical unit of field
TTYPE3  = 'GROUPING'           / label for field   3
TFORM3  = 'I       '           / data format of the field: 2-byte INTEGER
EXTNAME = 'SPECTRUM'           / name of this binary table extension
TLMIN1  =                    0 / Lowest legal channel number
TLMAX1  =                 1023 / Highest legal channel number
POISSERR=                    T / Poissonian errors to be assumed
STAT_ERR=                    0 / no statistical error specified
SYS_ERR =                    0 / no systematic error specified
QUALITY =                    0 / no data quality information specified
DETCHANS=                 1024 / Total No. of Detector Channels available

Additional Mandatory keywords for XSPEC (in addition to those above)

EXPOSURE=  2.91189522666037082672E+04 / Exposure time
AREASCAL=  0.1000000000000E+01  /nominal effective area
CORRSCAL=  0.1000000000000E+01  /correlation scale factor
BACKSCAL=  0.2815246582031E-01  /background scale factor
BACKFILE= 'back.sp '           / background FITS file for
CORRFILE= 'none    '           / correlation FITS file for
RESPFILE= 'none    '           / redistribution
ANCRFILE= 'none    '           / ancillary response
CHANTYPE= 'PI      '           / Channels assigned by detector electronics
HDUCLASS= 'OGIP    '           / format conforms to OGIP standard
HDUCLAS1= 'SPECTRUM'           / PHA dataset (OGIP memo OGIP-92-007)
HDUVERS = '1.2.1   '           / Version of format (OGIP memo OGIP-92-007)
TELESCOP= 'ASCA    '           / Telescope (mission) name
INSTRUME= 'GIS2    '           / Instrument name
FILTER  = 'none    '           / Instrument filter in use

Additional Optional (but recommended) keywords

DATAMODE= 'PH      '           / Datamode
XFLT0001= 'none    '           / XSPEC selection filter description
OBJECT  = 'BD +30 3639'        / Name of observed object
USER    = 'kaa     '           / User name of creator
FILIN001= 'screen.evt'         / Input file name
ORIGIN  = 'NASA/GSFC'          / origin of fits file
DATE    = '1995-02-07'         / FITS file creation date (yyyy-mm-dd)
EQUINOX =               2000.0 / Equinox of celestial coord system
RADECSYS= 'FK4     '           / coord frame used for EQUINOX
DATE-OBS= '1994-10-29'         / Date observations were made (yyyy-mm-dd)
TIME-OBS= '23:34:56'           / Time observations were made (hh:mm:ss)
DATE-END= '1994-10-30'         / Date observations ended (yyyy-mm-dd)
TIME-END= '18:30:56'           / Time observations ended (hh:mm:ss)
HDUCLAS2= '        '           / WARNING This is NOT an OGIP-approved value
HDUCLAS3= 'COUNT   '           / PHA data stored as Counts (not count/s)
HDUVERS1= '1.2.1   '           / Obsolete - included for backwards compatibility
TOTCTS  =                 1080 / Total counts in spectrum
END

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Last modified: Thursday, 21-Oct-2021 12:50:38 EDT