.. _bat-headers:

**************************************************************
Swift BAT FITS Headers (:mod:`gdt.missions.swift.bat.headers`)
**************************************************************
This module defines all of the FITS headers for the public data files. While
these classes are not usually directly called by the user, we may load one up
and see the contents and default values.  For example, here is the set of
header definitions for PHA files:

    >>> from gdt.missions.swift.bat.headers import PhaHeaders
    >>> hdrs = PhaHeaders()
    >>> hdrs
    <PhaHeaders: 4 headers>

Here is the ``PRIMARY`` header and default values (retrieved by index):

    >>> hdrs[0]
    TELESCOP= 'SWIFT   '           / Telescope (mission) name
    INSTRUME= 'BAT     '           /  Instrument name
    OBS_ID  = '' / Observation ID
    TARG_ID =                    0 / Target ID
    SEG_NUM =                    0 / Segment number
    TIMESYS = 'TT      '           / time system
    MJDREFI =                51910 / MJD reference day Jan 2001 00:00:00
    MJDREFF = '7.428703703703703e-4' / MJD reference (fraction of day) 01 Jan 2001 0
    CLOCKAPP= '' / If clock correction are applied (F/T)
    TIMEUNIT= 's       '           / Time unit for timing header keywords
    TSTART  =                  0.0 / As in the TIME column
    TSTOP   =                  0.0 / As in the TIME column
    DATE-OBS= ''
    DATE-END= ''
    ORIGIN  = 'NASA/GSFC'          / file creation location
    CREATOR = '' / file creator
    TLM2FITS= '' / Telemetry converter version number
    DATE    = '2024-02-12T20:02:15.863' / file creation date (YYYY-MM-DDThh:mm:ss UT
    NEVENTS =                    0 / Number of events
    DATAMODE= '' / Datamode
    OBJECT  = '' / Object name
    MJD-OBS =                  0.0 / MJD of data start time
    TIMEREF = 'LOCAL   '           / reference time
    EQUINOX =               2000.0 / Equinox for pointing RA/Dec
    RADECSYS= 'FK5     '           / Coordinates System
    USER    = '' / User name of creator
    FILIN001= '' / Input file name
    TIMEZERO=                  0.0 / Time Zero
    CHECKSUM= '' / HDU checksum updated 2020-06-07T06:49:01
    DATASUM = '' / data unit checksum updated 2020-06-07T06:32:34
    PROCVER = '' / Processing script version
    SOFTVER = ''
    CALDBVER= '' / CALDB index versions used
    SEQPNUM =                    0 / Number of times the dataset processed
    RA_OBJ  =                  0.0 / [deg] R.A. Object
    DEC_OBJ =                  0.0 / [dec] Dec Object
    RA_PNT  =                  0.0 / [deg] RA pointing
    DEC_PNT =                  0.0 / [deg] Dec pointing
    PA_PNT  =                  0.0 / [deg] Position angle (roll)
    TRIGTIME=                  0.0 / MET TRIGger Time for Automatic Target
    CATSRC  = ''
    ATTFLAG =                  100 / Attitude origin: 100=sat/spacecraft
    UTCFINIT=                  0.0 / [s] UTCF at TSTART


And here is the ``SPECTRUM`` header and default values:

    >>> EXTNAME = 'SPECTRUM'           / name of this binary table extension
    HDUCLASS= '' / Conforms to OGIP/GSFC standards
    HDUCLAS1= '' / Contains spectrum
    GAINAPP = '' / Gain correction has been applied
    TIMESYS = 'TT      '           / time system
    MJDREFI =                51910 / MJD reference day Jan 2001 00:00:00
    MJDREFF = '7.428703703703703e-4' / MJD reference (fraction of day) 01 Jan 2001 0
    TIMEREF = 'LOCAL   '           / reference time
    TASSIGN = 'SATELLITE'          / Time assigned by clock
    TIMEUNIT= 's       '           / Time unit for timing header keywords
    TIERRELA=                  0.0 / [s/s] relative errors expressed as rate
    TIERABSO=                  0.0 / [s] timing  precision  in seconds
    TRIGTIME=                  0.0 / MET TRIGger Time for Automatic Target
    TSTART  =                  0.0 / As in the TIME column
    TSTOP   =                  0.0 / As in the TIME column
    DATE-OBS= ''
    DATE-END= ''
    CLOCKAPP= '' / If clock correction are applied (F/T)
    TELAPSE =                  0.0 / [s] Total elapsed time from start to stop
    ONTIME  =                  0.0 / [s] Accumulated on-time
    LIVETIME=                  0.0 / [s] ONTIME multiplied by DEADC
    EXPOSURE=                  0.0 / [s] Accumulated exposure
    DEADC   =                  0.0 / Dead time correction factor
    TIMEPIXR=                  0.0 / Time bin alignment
    TIMEDEL =                  0.0 / [s] time resolution of data
    TELESCOP= 'SWIFT   '           / Telescope (mission) name
    INSTRUME= 'BAT     '           /  Instrument name
    DATAMODE= '' / Datamode
    OBS_ID  = '' / Observation ID
    TARG_ID =                    0 / Target ID
    SEG_NUM =                    0 / Segment number
    EQUINOX =               2000.0 / Equinox for pointing RA/Dec
    RADECSYS= 'FK5     '           / Coordinates System
    OBS_MODE= '' / default
    ORIGIN  = 'NASA/GSFC'          / file creation location
    CREATOR = '' / file creator
    TLM2FITS= '' / Telemetry converter version number
    DATE    = '2024-02-12T20:02:15.863' / file creation date (YYYY-MM-DDThh:mm:ss UT
    PROCVER = '' / Processing script version
    SOFTVER = ''
    CALDBVER= '' / CALDB index versions used
    SEQPNUM =                    0 / Number of times the dataset processed
    RA_OBJ  =                  0.0 / [deg] R.A. Object
    DEC_OBJ =                  0.0 / [dec] Dec Object
    RA_PNT  =                  0.0 / [deg] RA pointing
    DEC_PNT =                  0.0 / [deg] Dec pointing
    PA_PNT  =                  0.0 / [deg] Position angle (roll)
    CATSRC  = ''
    ATTFLAG =                  100 / Attitude origin: 100=sat/spacecraft
    UTCFINIT=                  0.0 / [s] UTCF at TSTART
    CHECKSUM= '' / HDU checksum updated 2020-06-07T06:49:01
    DATASUM = '' / data unit checksum updated 2020-06-07T06:32:34

See :external:ref:`Data File Headers<core-headers>` for more information about
creating and using FITS headers.

Reference/API
=============

.. automodapi:: gdt.missions.swift.bat.headers
   :inherited-members: