NOAO Mosaic Camera FITS Keyword Dictionary: Version 1

This is a draft. Changes are still being made. There may be errors.

This keyword dictionary defines all keywords which may be used in image data recorded by the data acquisition system. Not all keywords need to be used. New parameters must be added to the logical class heirarchy and then a keyword defined in this dictionary before use in image data. The logical class heirarchy is defined in the NOAO Image Data Structure Definitions.

Each keyword definition has the following fields.

NAME
The logical class name as given in the NOAO Image Data Structure Definitions.
KEYWORD
The FITS keyword. The convention for the numerically indexed keywords is given below.
DEFAULT
If a value is given it is either the name of another keywords or the value assumed if no keyword is present.
HDU
A recommendation for whether the keyword should be part of the primary or extension header-data unit when image extensions are used with multiple amplifiers and CCDs. For a single amplifier observation there is only a primary header with data and the HDU recommendation is not applicable.
VALUE
The data type of the value field and units. The datatypes are 'integer' or 'real' for FITS integer or real numbers, boolean for FITS boolean with values T and F, 'string' for FITS string values, 'sexagesimal' for numbers encoded as FITS strings in integer hours/degrees, integer minutes, and real seconds using colons for the field separators, 'date' for FITS format date string, 'section' for IRAF-style section given as a FITS string, and 'checksum'/'datasum' for the proposed check sum encoding as a FITS string. The units, in parenthesis, are as specified or may be be substituted by the applicable units.
COMMENT
The default comment in a FITS card. This is only a default and a more appropriate and detailed comment may be used.
EXAMPLE
An example keyword value.
DESCRIPTION
The description of the keyword and logical parameter.

The entries in the dictionary have the following conventions and rules.

A table of the keywords, defaults, and logical names is given in Table 1: FITS Keyword to Logical Name Mapping.


NAME:         Telescope.Adc.Version.hardware
KEYWORD:      ADC
HDU:          primary
VALUE:        string
COMMENT:      ADC Identification
EXAMPLE:      'Mayall ADC'
DESCRIPTION:
    Atmospheric dispersion compensator hardware identification.


NAME:         Observation.airmass[n]
KEYWORD:      AIRMASSn
HDU:          primary
VALUE:        real
COMMENT:      Airmass
EXAMPLE:      1.080
DESCRIPTION:
    The computed airmass(es) at the time(s) given by the AMMJDn keywords. 


NAME:         Detector.Ccd[n].Amp[n].Controller.integration
KEYWORD:      AMPINTEG
HDU:          primary | extension
VALUE:        real (ns)
COMMENT:      Amplifier integration/sample time (ns)
EXAMPLE:      15000.
DESCRIPTION:
    Amplifier integration or sample time.


NAME:         Detector.Ccd[n].Amp[n].name
KEYWORD:      AMPNAME
HDU:          extension
VALUE:        AMPNAME Dictionary
COMMENT:      Amplifier name
EXAMPLE:      'Amplifier 1'
DESCRIPTION:
    Amplifier name.


NAME:         Detector.Ccd[n].Amp[n].Amptrans.section
KEYWORD:      AMPSEC
HDU:          extension
VALUE:        section
COMMENT:      Amplifier section
EXAMPLE:      '[1:2048,2048:1]'
DESCRIPTION:
    Mapping of the CCD section to amplifier coordinates.


NAME:         Detector.Ccd[n].Amp[n].Controller.Arcon.gain
KEYWORD:      ARCONG
HDU:          extension
VALUE:        real (e/ADU)
COMMENT:      Predicted gain (e/ADU)
EXAMPLE:      3.2
DESCRIPTION:
    Arcon predicted gain.  This is the gain measured in the laboratory.
    The GAIN keyword may also have this value initially but it is
    updated to the most recent estimate of the gain.


NAME:         Detector.Ccd[n].Amp[n].Controller.Arcon.gainindex
KEYWORD:      ARCONGI
HDU:          extension
VALUE:        integer
COMMENT:      Gain selection (index into Gain Table)
EXAMPLE:      2
DESCRIPTION:
    Arcon gain index value.


NAME:         Detector.Ccd[n].Amp[n].Controller.Arcon.readnoise
KEYWORD:      ARCONRN
HDU:          extension
VALUE:        real (e)
COMMENT:      Predicted readout noise (e)
EXAMPLE:      3.9
DESCRIPTION:
    Arcon predicted RMS readout noise.  This is the value measured in
    the laboratory.  The RDNOISE keyword may also have this value initially
    but it is updated to the most current estimate.


NAME:         Detector.Ccd[n].Amp[n].Controller.Arcon.wavedate
KEYWORD:      ARCONWD
HDU:          primary | extension
VALUE:        string
COMMENT:      Date CCD waveforms last compiled
EXAMPLE:      'Obs Fri Nov 10 22:50:17 1995'
DESCRIPTION:
    Arcon waveform complilation date.


NAME:         Detector.Ccd[n].Amp[n].Controller.Arcon.wavemode
KEYWORD:      ARCONWM
HDU:          primary | extension
VALUE:        string
COMMENT:      Arcon waveform options enabled
EXAMPLE:      'OverlapXmit EarlyReset'
DESCRIPTION:
    Arcon waveform options enabled.


NAME:         Detector.Ccd[n].Amp[n].Amptrans.tm[i,j]
KEYWORD:      ATMi_j
DEFAULT:      0.0 (i!=j), 1.0 (i=j)
HDU:          extension
VALUE:        real
COMMENT:      Amplifier transformation matrix
EXAMPLE:      1.00
DESCRIPTION:
    Transformation matrix between CCD and amplifier coordinates.
    Normally only two values will be non-zero and will have values of
    1 or -1.  If missing the default is an identify matrix.


NAME:         Detector.Ccd[n].Amp[n].Amptrans.tv[i]
KEYWORD:      ATVi
DEFAULT:      0.0
HDU:          extension
VALUE:        real
COMMENT:      Amplifier transformation vector
EXAMPLE:      1.00
DESCRIPTION:
    Transformation origin vector between CCD and amplifier coordinates.


NAME:         Detector.Ccd[n].Amp[n].biassec[1]
KEYWORD:      BIASSEC
HDU:          extension
VALUE:        section
COMMENT:      Bias section
EXAMPLE:      '[2049:2080,1:2048]'
DESCRIPTION:
    Section of the recorded image containing overscan or prescan data.  This
    will be in binned pixels if binning is done.  Multiple regions may be
    recorded and specified, such as both prescan and overscan, but the
    first section given by this parameter is likely to be the one used
    during calibration.


NAME:         Image.bitpix
KEYWORD:      BITPIX
HDU:          primary & extension
VALUE:        integer
COMMENT:      Number of bits per pixel
EXAMPLE:      16
DESCRIPTION:
    Required FITS format keyword.


NAME:         Detector.Ccd[n].Badpixels.badpixels
KEYWORD:      BPM
HDU:          primary | extension
VALUE:        string (filename)
COMMENT:      Bad pixels
EXAMPLE:      'mosccd7.pl'
DESCRIPTION:
    Description of bad pixels.  The value is an IRAF bad pixel mask name.


NAME:         Image.bscale
KEYWORD:      BSCALE
DEFAULT:      1.
HDU:          primary & extension
VALUE:        real
COMMENT:      Scale factor
EXAMPLE:      2.
DESCRIPTION:
    Conversion from file value to data value: data = BSCALE * file + BZERO.
    Only used if BITPIX is positive.


NAME:         Image.bzero
KEYWORD:      BZERO
DEFAULT:      0.
HDU:          primary & extension
VALUE:        real
COMMENT:      Zero factor
EXAMPLE:      -32768.
DESCRIPTION:
    Conversion from file value to data value: data = BSCALE * file + BZERO.
    Only used if BITPIX is positive.  A value of -32768 is used to record
    unsigned short integer data.


NAME:         Detector.Ccd[n].name
KEYWORD:      CCDNAME
DEFAULT:      DETECTOR
HDU:          primary | extension
VALUE:        CCDNAME Dictionary
COMMENT:      CCD identification
EXAMPLE:      'T2KA    '
DESCRIPTION:
    CCD identification.


NAME:         Detector.Ccd[n].Amp[n].section
KEYWORD:      CCDSEC
DEFAULT:      CCDSIZE
HDU:          extension
VALUE:        section
COMMENT:      Region of CCD read
EXAMPLE:      '[1:2048,1:2048]'
DESCRIPTION:
    The unbinned section of the logical CCD pixel raster covered by the
    amplifier readout in section notation.  The section must map directly
    to the specified data section through the binning and CCD to
    image coordiante transformation.  The image data section (DATASEC)
    is specified with the starting pixel less than the ending pixel.
    Thus the order of this section may be flipped depending on the
    coordinate transformation (which depends on how the CCD coordinate
    system is defined).


NAME:         Detector.Ccd[n].ccdsize
KEYWORD:      CCDSIZE
DEFAULT:      DETSIZE
HDU:          primary | extension
VALUE:        section
COMMENT:      CCD size
EXAMPLE:      '[1:2048,1:2048]'
DESCRIPTION:
    The logical unbinned size of the CCD in section notation.  Normally
    this would be the physical size of the CCD unless drift scanning
    is done.  This is the full size even when subraster readouts are
    done.


NAME:         Detector.Ccd[n].Amp[n].binning
KEYWORD:      CCDSUM
DEFAULT:      '1 1'
HDU:          extension
VALUE:        string (integer integer [integer integer])
COMMENT:      CCD on-chip summing
EXAMPLE:      '1 1     '
DESCRIPTION:
    CCD on-chip summing given as two or four integer numbers.  These define
    the summing of CCD pixels in the amplifier readout order.  The first
    two numbers give the number of pixels summed in the serial and parallel
    directions respectively.  If the first pixel read out consists of fewer
    unbinned pixels along either direction the next two numbers give the
    number of pixels summed for the first serial and parallel pixels.  From
    this it is implicit how many pixels are summed for the last pixels
    given the size of the CCD section (CCDSEC).  It is highly recommended
    that controllers read out all pixels with the same summing in which
    case the size of the CCD section will be the summing factors times the
    size of the data section.


NAME:         Detector.Ccd[n].Sensors.temperature[n]
KEYWORD:      CCDTEMn
HDU:          primary | extension
VALUE:        real (deg C)
COMMENT:      CCD temperature (deg C)
EXAMPLE:      -104.
DESCRIPTION:
    CCD temperature sensor measurements in degrees Celsius.


NAME:         Detector.Ccd[n].Amp[n].Wcs.cd[i,j]
KEYWORD:      CDi_j
DEFAULT:      0.0
HDU:          extension
VALUE:        real
COMMENT:      Coordinate scale matrix
EXAMPLE:      1.00
DESCRIPTION:
    Coordinate scale matrix for image world coordinates.  This describes
    the scales and rotations of the coordinate axes.  The IRAF WCS
    standards are used.


NAME:         Image.Checksum.header
KEYWORD:      CHECKSUM
HDU:          primary & extension
VALUE:        checksum
COMMENT:      Header checksum
EXAMPLE:      '0WDA3T940TA90T99'
DESCRIPTION:
    Header checksum value for verifying the data.  This follows the
    proposed FITS checksum standard.


NAME:         Image.Checksum.version
KEYWORD:      CHECKVER
HDU:          primary & extension
VALUE:        string
COMMENT:      Checksum version
EXAMPLE:      'complement'
DESCRIPTION:
    Version of checksum method used for the checksums.


NAME:         Detector.Ccd[n].Amp[n].Controller.hardware
KEYWORD:      CONHWV
HDU:          primary | extension
VALUE:        string
COMMENT:      Controller hardware version
EXAMPLE:      'Arcon V1.0'
DESCRIPTION:
    Controller hardware version.


NAME:         Detector.Ccd[n].Amp[n].Controller.software
KEYWORD:      CONSWV
HDU:          primary | extension
VALUE:        string
COMMENT:      Controller software version
EXAMPLE:      'Arcon V1.0'
DESCRIPTION:
    Controller software version.


NAME:         Detector.Ccd[n].Amp[n].Controller.name
KEYWORD:      CONTROLR
HDU:          primary | extension
VALUE:        string
COMMENT:      Detector controller
EXAMPLE:      'Arcon V1.0'
DESCRIPTION:
    Detector controller name.


NAME:         Telescope.Corrector[1]
KEYWORD:      CORRCTOR
HDU:          primary
VALUE:        string
COMMENT:      Corrector Identification
EXAMPLE:      'doublet '
DESCRIPTION:
    Correctors in the optical path.


NAME:         Detector.Ccd[n].Amp[n].Wcs.crpix[i]
KEYWORD:      CRPIXi
DEFAULT:      0.0
HDU:          extension
VALUE:        real (pixels)
COMMENT:      Coordinate reference pixel
EXAMPLE:      1.00
DESCRIPTION:
    Coordinate reference pixel for image world coordinates.  The IRAF
    WCS standards are used (which is the FITS standard).


NAME:         Detector.Ccd[n].Amp[n].Wcs.crval[i]
KEYWORD:      CRVALi
DEFAULT:      0.0
HDU:          extension
VALUE:        real
COMMENT:      Coordinate reference value
EXAMPLE:      1.00
DESCRIPTION:
    Coordinate reference value for image world coordinates.  For celestial
    coordinates the coordinate system, equinox, and epoch are given by the
    keywords WCSRADEC, WCSEQUIN, and WCSEPOCH.  The units follow the IRAF
    standard (which is the FITS standard); i.e. right ascension
    and declination in decimal degrees.


NAME:         Detector.Ccd[n].Amp[n].Wcs.ctype[i]
KEYWORD:      CTYPEi
DEFAULT:      'LINEAR'
HDU:          extension
VALUE:        string
COMMENT:      Coordinate type
EXAMPLE:      'LINEAR  '
DESCRIPTION:
    Coordinate type for image world coordinates.  The IRAF WCS standards
    are used (which is generally the FITS standard).


NAME:         Detector.Ccd[n].Amp[n].Exp.darktime
KEYWORD:      DARKTIME
DEFAULT:      EXPTIME
HDU:          primary & extension
VALUE:        real (sec)
COMMENT:      Dark time (sec)
EXAMPLE:      600
DESCRIPTION:
    Total dark time of the observation.  This is the total time during
    which dark current is collected by the detector.  If the times in the
    extension are different the primary HDU gives one of the extension
    times.


NAME:         Detector.Ccd[n].Amp[n].Imagetrans.section
KEYWORD:      DATASEC
HDU:          extension
VALUE:        section
COMMENT:      Image data section
EXAMPLE:      '[33:2080,1:2048]'
DESCRIPTION:
    Mapping of the CCD section to image coordinates.


NAME:         Image.Checksum.data
KEYWORD:      DATASUM
HDU:          primary & extension
VALUE:        datasum
COMMENT:      Data checksum
EXAMPLE:      'aMmjbMkhaMkhaMkh'
DESCRIPTION:
    Data checksum value for verifying the data.  This follows the
    proposed FITS checksum standard.


NAME:         Detector.Ccd[n].Amp[n].Exp.Expstart.date
KEYWORD:      DATE-OBS
HDU:          primary & extension
VALUE:        date
COMMENT:      Date of observation start
EXAMPLE:      '05/04/87'
DESCRIPTION:
    Date of observation in TIMESYS time system at the start of the exposure.
    The format follows the FITS 'date' standard.


NAME:         Coordinate.dec
KEYWORD:      DEC
HDU:          primary & extension
VALUE:        sexagesimal (deg)
COMMENT:      Declination (deg)
EXAMPLE:      '47:15:34.00'
DESCRIPTION:
    Default declination in degrees.


NAME:         Detector.Projection.decposangle
KEYWORD:      DECPANGL
HDU:          primary
VALUE:        real (deg)
COMMENT:      Position angle of Dec axis (deg)
EXAMPLE:      0.0
DESCRIPTION:
    Projected position angle of the positive declination axis on the
    detector.  The position angle is measured clockwise from the image y
    axis.


NAME:         Detector.name
KEYWORD:      DETECTOR
HDU:          primary
VALUE:        DETECTOR Dictionary
COMMENT:      Detector name
EXAMPLE:      'T2KA    '
DESCRIPTION:
    Detector name.


NAME:         Detector.Ccd[n].Amp[n].Dettrans.section
KEYWORD:      DETSEC
HDU:          extension
VALUE:        section
COMMENT:      Detector data section
EXAMPLE:      '[2049:4096,1:2048]'
DESCRIPTION:
    Mapping of the CCD section to detector coordinates.


NAME:         Detector.size
KEYWORD:      DETSIZE
HDU:          primary
VALUE:        section
COMMENT:      Detector size
EXAMPLE:      '[1:2048,1:2048]'
DESCRIPTION:
    The logical unbinned size of the  detector in section notation.  This
    is the full pixel raster size including, if applicable, drift scanning
    or a mosaic format.  This is the full size even when subraster
    readouts are done.


NAME:         Detector.Ccd[n].Dewar.name
KEYWORD:      DEWAR
HDU:          primary
VALUE:        DEWAR Dictionary
COMMENT:      Dewar
EXAMPLE:      'Universal Dewar #2'
DESCRIPTION:
    Dewar identification.


NAME:         Detector.Ccd[n].Dewar.Sensors.temperature[n]
KEYWORD:      DEWTEMn
HDU:          primary | extension
VALUE:        real (deg C)
COMMENT:      Dewar temperature (deg C)
EXAMPLE:      -91.
DESCRIPTION:
    Dewar temperature sensor measurements in degrees Celsius.


NAME:         Detector.Ccd[n].Amp[n].Dettrans.tm[i,j]
KEYWORD:      DTMi_j
DEFAULT:      0.0 (i!=j), 1.0 (i=j)
HDU:          extension
VALUE:        real
COMMENT:      Detector transformation matrix
EXAMPLE:      1.00
DESCRIPTION:
    Transformation matrix between CCD and detector coordinates.
    If missing the default is an identify matrix.


NAME:         Detector.Ccd[n].Amp[n].Dettrans.tv[i]
KEYWORD:      DTVi
DEFAULT:      0.0
HDU:          extension
VALUE:        real
COMMENT:      Detector transformation vector
EXAMPLE:      1.00
DESCRIPTION:
    Transformation origin vector between CCD and detector coordinates.


NAME:         Image.end
KEYWORD:      END
HDU:          primary & extension
VALUE:        
COMMENT:      
EXAMPLE:      
DESCRIPTION:
    Required FITS keyword ending a header.  This may be moved to the
    end of the last FITS 2880 byte header record leaving blank lines between
    the last card and the END card for runtime expansion.


NAME:         Site.Environment.temperature[n]
KEYWORD:      ENVTEMn
HDU:          primary
VALUE:        real (deg C)
COMMENT:      Site temperature (deg C)
EXAMPLE:      61.10
DESCRIPTION:
    Temperatures outside the dome at times given by ENVMJDn keywords.


NAME:         Coordinate.equinox
KEYWORD:      EQUINOX
DEFAULT:      2000.0
HDU:          primary & extension
VALUE:        real (years)
COMMENT:      Default coordinate equinox
EXAMPLE:      2000.0
DESCRIPTION:
    Default coordinate system equinox.  A values before 1984 is Besselian
    otherwise it is Julian.  If absent the default is J2000.


NAME:         Detector.Ccd[n].Amp[n].Exp.exptime
KEYWORD:      EXPTIME
HDU:          primary & extension
VALUE:        real (sec)
COMMENT:      Exposure time (sec)
EXAMPLE:      600
DESCRIPTION:
    Total exposure time of the observation.  This is the total time during
    which photons are collected by the detector.  It includes any shutter
    correction.  If the times in the extension are different the primary
    HDU gives one of the extension times.


NAME:         Image.extend
KEYWORD:      EXTEND
HDU:          primary
VALUE:        boolean
COMMENT:      File contains extensions
EXAMPLE:      T
DESCRIPTION:
    Required FITS keyword when there are extensions.


NAME:         Image.extname
KEYWORD:      EXTNAME
HDU:          extension
VALUE:        string
COMMENT:      Extension name
EXAMPLE:      'im1     '
DESCRIPTION:
    The extension name which can be used to reference a specific image in
    the image extension format.  For ease of use it should be short.  The
    recommended name is im#, where # is the amplifier/extension version
    number.


NAME:         Image.extver
KEYWORD:      EXTVER
HDU:          extension
VALUE:        integer
COMMENT:      Extension version
EXAMPLE:      3
DESCRIPTION:
    The extension version number which is identical to IMAGEID.
    For detectors with CCDs this would be the unique amplifier number
    within the detector.


NAME:         Image.filename
KEYWORD:      FILENAME
HDU:          primary
VALUE:        string
COMMENT:      Original host filename
EXAMPLE:      'dflat313'
DESCRIPTION:
    Filename used to record the original data.


NAME:         Filter[n].position
KEYWORD:      FILPOSn
HDU:          primary
VALUE:        real (instrumental)
COMMENT:      Filter system position
EXAMPLE:      5.
DESCRIPTION:
    Filter position given as filter wheel number or other filter system
    position measurement.


NAME:         Filter[n].name
KEYWORD:      FILTERn
HDU:          primary & extension
VALUE:        FILTER Dictionary
COMMENT:      Filter name
EXAMPLE:      'V       '
DESCRIPTION:
    Filter names.  This name is the astronomical standard name if
    applicable; i.e. U, B, Gunn I, etc.  The filter type and filter device
    position are given by other keywords.


NAME:         Detector.Ccd[n].Amp[n].Controller.gain
KEYWORD:      GAIN
HDU:          extension
VALUE:        real (electrons/ADU)
COMMENT:      Amplifier gain (e/ADU)
EXAMPLE:      4.3
DESCRIPTION:
    Amplifier gain in electrons per analog unit.  This is the most current
    estimate of the gain.


NAME:         Image.gcount
KEYWORD:      GCOUNT
HDU:          extension
VALUE:        integer
COMMENT:      Number of groups
EXAMPLE:      1
DESCRIPTION:
    Required FITS standard keyword in extensions.


NAME:         Observation.imageid
KEYWORD:      IMAGEID
HDU:          extension
VALUE:        integer
COMMENT:      Image identification
EXAMPLE:      1
DESCRIPTION:
    The image identification when there are multiple images within
    an observation.  For detectors with CCDs this would be a unique
    number assigned to each amplifier in the detector.


NAME:         Image.Version.software
KEYWORD:      IMAGESWV
HDU:          primary
VALUE:        string
COMMENT:      Image creation software version
EXAMPLE:      'DCA (Jun96) with mosaic.tcl (Aug97)'
DESCRIPTION:
    Image creation system software version.


NAME:         Image.inherit
KEYWORD:      INHERIT
HDU:          extension
VALUE:        boolean
COMMENT:      Inherit global keywords?
EXAMPLE:      T
DESCRIPTION:
    Parameter to indicate whether the global keywords are to be inherited
    by the image extension.


NAME:         Archive.dictionary
KEYWORD:      KWDICT
HDU:          primary
VALUE:        string
COMMENT:      Keyword dictionary
EXAMPLE:      'NOAO FITS Keyword Dictionary (Aug97)'
DESCRIPTION:
    The keyword dictionary defining the keywords.  This dictionary
    should be archived with the data.


NAME:         Image.Header.lst
KEYWORD:      LSTHDR
DEFAULT:      LST-OBS
HDU:          primary & extension
VALUE:        sexagesimal (hours)
COMMENT:      LST of header creation
EXAMPLE:      '14:53:42.00'
DESCRIPTION:
    Local siderial time of the header creation.


NAME:         Detector.Ccd[n].Amp[n].Imagetrans.tm[i,j]
KEYWORD:      LTMi_j
DEFAULT:      0.0 (i!=j), 1.0 (i=j)
HDU:          extension
VALUE:        real
COMMENT:      Image transformation matrix
EXAMPLE:      1.00
DESCRIPTION:
    Transformation matrix between CCD and image coordinates.
    If missing the default is an identify matrix.


NAME:         Detector.Ccd[n].Amp[n].Imagetrans.tv[i]
KEYWORD:      LTVi
DEFAULT:      0.0
HDU:          extension
VALUE:        real
COMMENT:      Image transformation vector
EXAMPLE:      1.00
DESCRIPTION:
    Transformation origin vector between CCD and image coordinates.


NAME:         Detector.Ccd[n].Amp[n].Exp.Expstart.mjd
KEYWORD:      MJD-OBS
HDU:          primary & extension
VALUE:        real (days)
COMMENT:      MJD of observation
EXAMPLE:      46890.394063
DESCRIPTION:
    Modified Julian date at the start of the exposure.  The fractional
    part of the date is given to better than a second of time.


NAME:         Image.Header.mjd
KEYWORD:      MJDHDR
DEFAULT:      MJD-OBS
HDU:          primary & extension
VALUE:        real (days)
COMMENT:      MJD of header creation
EXAMPLE:      46890.394063
DESCRIPTION:
    Modified Julian date when the image header was created by the software.
    The fractional part of the date is given to better than a second of time.
    Many header keywords may be sampled or computed at this time and this
    keyword is the default for these.


NAME:         Detector.namps
KEYWORD:      NAMPS
DEFAULT:      1
HDU:          primary
VALUE:        integer
COMMENT:      Number of Amplifiers
EXAMPLE:      1
DESCRIPTION:
    The number of amplifiers in the detector.  When there is only a single
    amplifier used it may be absent since the default value is 1.


NAME:         Image.naxis
KEYWORD:      NAXIS
HDU:          primary & extension
VALUE:        integer
COMMENT:      Number of image axes
EXAMPLE:      2.
DESCRIPTION:
    Required FITS format keyword.


NAME:         Image.naxis[i]
KEYWORD:      NAXISi
HDU:          primary & extension
VALUE:        integer
COMMENT:      Number of pixels along axis
EXAMPLE:      2048
DESCRIPTION:
    Required FITS format keywords.


NAME:         Detector.nccds
KEYWORD:      NCCDS
DEFAULT:      1
HDU:          primary
VALUE:        integer
COMMENT:      Number of CCDs
EXAMPLE:      1
DESCRIPTION:
    The number of CCDs in the detector.  This is used with mosaics of CCD
    detectors.  For a single CCD it may be absent since the default value
    is 1.


NAME:         Image.nextend
KEYWORD:      NEXTEND
HDU:          primary
VALUE:        integer
COMMENT:      Number of extensions
EXAMPLE:      8
DESCRIPTION:
    Number of extensions in FITS file.


NAME:         Observation.title
KEYWORD:      OBJECT
HDU:          primary & extnsion
VALUE:        string
COMMENT:      Observation title
EXAMPLE:      'm51 V 600s'
DESCRIPTION:
    The observation title given by the observer.  This will often be
    the name of the astronomical target object but the standard
    object name should be given in the OBJNAME keyword.


NAME:         Site.observatory
KEYWORD:      OBSERVAT
HDU:          primary
VALUE:        OBSERVAT Dictionary
COMMENT:      Observatory
EXAMPLE:      'KPNO    '
DESCRIPTION:
    Observatory identification for the site of the observation.


NAME:         Observer.name[1]
KEYWORD:      OBSERVER
HDU:          primary
VALUE:        string
COMMENT:      Observer(s)
EXAMPLE:      'G. Jacoby, D. Tody, F. Valdes'
DESCRIPTION:
    Name(s) of the observers.


NAME:         Observation.obsid
KEYWORD:      OBSID
HDU:          primary & extension
VALUE:        string
COMMENT:      Observation identification
EXAMPLE:      'kpno.36in.870405.257752'
DESCRIPTION:
    The unique observatory observation identification.  This serves
    to identify all data from the same observation.


NAME:         Observation.Obstype.type
KEYWORD:      OBSTYPE
HDU:          primary & extension
VALUE:        OBSTYPE Dictionary
COMMENT:      Observation type
EXAMPLE:      'OBJECT  '
DESCRIPTION:
    The type of observation such as an astronomical exposure or a
    particular type of calibration exposure.


NAME:         Image.pcount
KEYWORD:      PCOUNT
HDU:          extension
VALUE:        integer
COMMENT:      Number of pixels following data
EXAMPLE:      0
DESCRIPTION:
    Required FITS standard keyword in extensions.


NAME:         Detector.Projection.pixscale[i]
KEYWORD:      PIXSCALi
HDU:          primary
VALUE:        real (arcsec/pixel)
COMMENT:      Pixel scale (arcsec/pixel)
EXAMPLE:      15.9
DESCRIPTION:
    Projected pixel scale along axis n in arc seconds per pixel.


NAME:         Detector.Ccd[n].pixsize[i]
KEYWORD:      PIXSIZEi
HDU:          primary | extension
VALUE:        real (arbitrary)
COMMENT:      Pixel size ()
EXAMPLE:      
DESCRIPTION:
    Unbinned pixel size along each dimension given in appropriate units.
    The units should be indicated in the comment.  The projected pixel
    size in arc seconds or wavelength are given by other parameters.


NAME:         Detector.Ccd[n].preflash
KEYWORD:      PREFLASH
DEFAULT:      0.
HDU:          primary & extension
VALUE:        real (sec)
COMMENT:      Preflash time (sec)
EXAMPLE:      2.0
DESCRIPTION:
    CCD preflash time.  If the times in the extension are different the primary
    HDU gives one of the extension times.


NAME:         Observer.proposalid
KEYWORD:      PROPID
HDU:          primary
VALUE:        string
COMMENT:      Proposal identification
EXAMPLE:      'KPNO 12345'
DESCRIPTION:
    The unique observatory proposal identification.


NAME:         Observer.proposal
KEYWORD:      PROPOSAL
HDU:          primary
VALUE:        string
COMMENT:      Proposal title
EXAMPLE:      'Search for primeval galaxies'
DESCRIPTION:
    The name or title of the proposal.


NAME:         Observer.proposer[1]
KEYWORD:      PROPOSER
HDU:          primary
VALUE:        string
COMMENT:      Proposer(s)
EXAMPLE:      'G. Jacoby, D. Tody, F. Valdes'
DESCRIPTION:
    Name(s) of the proposers.


NAME:         Coordinate.ra
KEYWORD:      RA
HDU:          primary & extension
VALUE:        sexagesimal (hours)
COMMENT:      Right ascension (hours)
EXAMPLE:      '13:29:24.00'
DESCRIPTION:
    Default right ascension in hours.


NAME:         Coordinate.system
KEYWORD:      RADECSYS
DEFAULT:      'FK5'
HDU:          primary
VALUE:        RADECSYS Dictionary
COMMENT:      Default coordinate system
EXAMPLE:      'FK5     '
DESCRIPTION:
    Default coordinate system type.  If absent the default value is 'FK5'.


NAME:         Detector.Projection.raposangle
KEYWORD:      RAPANGL
HDU:          primary
VALUE:        real (deg)
COMMENT:      Position angle of RA axis (deg)
EXAMPLE:      -90.0
DESCRIPTION:
    Projected position angle of the positive right ascension axis on the
    detector.  The position angle is measured clockwise from the image y
    axis.


NAME:         Detector.Ccd[n].Amp[n].Controller.readnoise
KEYWORD:      RDNOISE
HDU:          extension
VALUE:        real (e)
COMMENT:      Readout noise (e)
EXAMPLE:      12.
DESCRIPTION:
    CCD readout noise in rms electrons.  This is the most current estimate.


NAME:         Detector.Ccd[n].Amp[n].Controller.saturate
KEYWORD:      SATURATE
HDU:          extension
VALUE:        real (ADU)
COMMENT:      Saturation value (ADU)
EXAMPLE:      65000.
DESCRIPTION:
    Pixel value above which the detector is saturated.


NAME:         Shutter.status
KEYWORD:      SHUTSTAT
HDU:          primary
VALUE:        SHUTSTAT Dictionary
COMMENT:      Shutter status
EXAMPLE:      'triggered'
DESCRIPTION:
    Shutter status.


NAME:         Image.simple
KEYWORD:      SIMPLE
HDU:          primary
VALUE:        boolean
COMMENT:      File conforms to FITS standard
EXAMPLE:      T
DESCRIPTION:
    Required FITS format keyword.


NAME:         Telescope.Coordinate.dec
KEYWORD:      TELDEC
DEFAULT:      DEC
HDU:          primary
VALUE:        sexagesimal (deg)
COMMENT:      Telescope declination (hours)
EXAMPLE:      '47:15:34.00'
DESCRIPTION:
    Telescope pointing declination in degrees.


NAME:         Telescope.Coordinate.equinox
KEYWORD:      TELEQUIN
DEFAULT:      EQUINOX
HDU:          primary
VALUE:        real (years)
COMMENT:      Telescope coordinate equinox
EXAMPLE:      2000.0
DESCRIPTION:
    Telescope pointing coordinate system equinox.


NAME:         Telescope.name
KEYWORD:      TELESCOP
HDU:          primary
VALUE:        TELESCOP Dictionary
COMMENT:      Telescope
EXAMPLE:      '0.9m    '
DESCRIPTION:
    Telescope used for the observation.


NAME:         Telescope.focus
KEYWORD:      TELFOCUS
HDU:          primary
VALUE:        real (arbitrary)
COMMENT:      Telescope focus
EXAMPLE:      1430
DESCRIPTION:
    Telescope focus value in available units.


NAME:         Telescope.Coordinate.ra
KEYWORD:      TELRA
DEFAULT:      RA
HDU:          primary
VALUE:        sexagesimal (hours)
COMMENT:      Telescope right ascension (hours)
EXAMPLE:      '13:29:24.00'
DESCRIPTION:
    Telescope pointing right ascension in hours.


NAME:         Telescope.Coordinate.system
KEYWORD:      TELRADEC
DEFAULT:      RADECSYS
HDU:          primary
VALUE:        RADECSYS Dictionary
COMMENT:      Telescope coordinate system
EXAMPLE:      'FK5     '
DESCRIPTION:
    Telescope pointing coordinate system type.


NAME:         Detector.Ccd[n].Amp[n].Exp.Expstart.time
KEYWORD:      TIME-OBS
HDU:          primary & extension
VALUE:        sexagesimal (hours)
COMMENT:      Time of observation start
EXAMPLE:      '09:27:27.00'
DESCRIPTION:
    Time of exposure start in the TSYSOBS system.


NAME:         timesys
KEYWORD:      TIMESYS
DEFAULT:      'UTC'
HDU:          primary
VALUE:        TIMESYS Dictionary
COMMENT:      Default time system
EXAMPLE:      'UTC approximate'
DESCRIPTION:
    Default time system.  All the MJD keywords which are not part of
    a TIME class are given in this time system.  This applys to all
    the SENSOR class times.


NAME:         Detector.Ccd[n].Amp[n].trimsec
KEYWORD:      TRIMSEC
DEFAULT:      DATASEC
HDU:          extension
VALUE:        section
COMMENT:      Section of useful data
EXAMPLE:      '[1:2048,1:2048]'
DESCRIPTION:
    Section of the recorded image to be kept after calibration processing.
    This is generally the part of the data section containing useful
    data.  The section is in in binned pixels if binning is done.


NAME:         Tv[n].focus[n]
KEYWORD:      TVnFOCn
HDU:          primary
VALUE:        real (arbitrary)
COMMENT:      Television focus
EXAMPLE:      1430
DESCRIPTION:
    Television focus value in available units.


NAME:         Image.xtension
KEYWORD:      XTENSION
HDU:          extension
VALUE:        string
COMMENT:      FITS extension type
EXAMPLE:      'IMAGE   '
DESCRIPTION:
    Required FITS keyword for extensions.  Extensions for CCD image
    data have the value 'IMAGE'.


NAME:         Telescope.zenith
KEYWORD:      ZD
HDU:          primary
VALUE:        real (deg)
COMMENT:      Zenith distance (deg)
EXAMPLE:      42.359
DESCRIPTION:
    Zenith distance of telescope pointing at TELMJD.