1 Language
    ALMA        : Joint deconvolution of ALMA and ACA dirty images
    CLARK       : Deconvolve a dirty image using the CLARK clean algorithm
    DUMP        : Dump the control parameters of the deconvolution algorithms
    FIT         : Fit the dirty beam
    FLUX        ! Cross-Check flux scales (experimental)
    HOGBOM      : Deconvolve a dirty image using the basic clean algorithm
    LOAD        : Load an image or cube into the W SIC variable
    MODIFY      : Change the Frequency / Velocity scale
    MOSAIC      : Toggle the mosaic mode
    MULTI       : Deconvolve a dirty image using the MULTI-SCALE Clean
    MRC         : Deconvolve a dirty image using the MULTI-RESOLUTION Clean
    MX          : Iteratively image and deconvolve a dirty image
    READ        : Read the input files in internal buffers
    SDI         : Deconvolve a dirty image using the Steer-Dewdney-Ito Clean
    SHOW        : Display (in a plot) some internal buffer result
    STATISTIC   : Compute statistics on image
    SUPPORT     : Define the support used to search clean components
    UV_BASELINE : Subtract a continuum baseline from a Line UV data
    UV_COMPRESS : Compress a Line UV data into another Line UV data
    UV_CONT     : Compress a Line UV data into a Continuum UV data
    UV_FILTER   : Filter out (line) channels
    UV_FLAG     : Interactively flag UV data
    UV_MAP      : Build the dirty image and beam from a UV table
    UV_RESAMPLE : Resample (in Velocity) the UV data
    UV_RESTORE  : Restore a Clean image from UV data and Clean Components
    UV_SORT     : Sort and Transpose UV data for plotting
    UV_STAT     : Gives beam sizes and noise properties as a function of
                   tapering or robust weighting parameter
    VIEW        : Show (in a GO VIEW-like plot) some internal buffer result
    WIPE        : Image and deconvolve a uv table using the wipe algorithm
    WRITE       : Save internal buffers into output files

1 ALMA
        [CLEAN\]ALMA [FirstPlane LastPlane] [/PLOT Clean|Residu] [/FLUX Fmin
    Fmax] [/QUERY] [/NOISE] [/METHOD]

    Joint deconvolution methods specific to ALMA+ACA observations.

    The ALMA simulator can be accessed either by  typing  "@  alma"  at  the
    prompt or from the MAPPING main menu.

1 CLARK
        [CLEAN\]CLARK  [FirstPlane  LastPlane]  [/PLOT  Clean|Residu] [/FLUX
    Fmin Fmax] [/QUERY]

    A Major-Minor cycles CLEAN method, originally developed by  B.Clark,  in
    which  clean components are selected using a limited beam patch, and de-
    convolved through Fourier transform at each major cycle. In mosaic  mode
    (See  command  MOSAIC), a mosaic clean is performed. Rings and/or strips
    may appear on extended sources.  Faster than the Hogbom method for  sin-
    gle  fields  but  maybe  slower  for mosaics. The strategy to search for
    CLEAN components in CLARK does not work properly when the secondary side
    lobes are too large (e.g. larger than 0.3).

    Clean  the  specified  plane interval (default: planes between variables
    FIRST and LAST). If option /PLOT is given, a display  of  the  CLEAN  or
    RESIDUAL  map  will be shown at each major cycle, depending on the argu-
    ment (default: Residual). The user will  be  prompted  for  continuation
    when  the /QUERY option is present. The cumulative, already cleaned flux
    is displayed in real time in an additional window while cleaning goes on
    when  the  /FLUX  option  is present. Parameters of the /FLUX option are
    then used to give the flux limits for this display.

    The user can control the algorithm  through  SIC  variables.  Values  of
    those variables can be checked through either "INPUT UV_MAP|CLEAN|UVALL"
    or "EXAMINE
     VARIABLE". New values can be given using "LET VARIABLE value". For ease
    of  use, and whenever it is possible, a sensible value of each parameter
    will automatically be computed from the context if the value of the cor-
    responding  variable  is  set  to its default value, i.e. zero value and
    empty string. A few variables are initialized to "reasonable" values.
    GAIN       [       ] Loop gain
    NITER      [       ] Maximum number of clean components
    FRES       [      %] Maximum value of residual (Fraction of peak)
    ARES       [Jy/Beam] Maximum value of residual (Absolute)
    BLC        [  pixel] Bottom left corner of cleaning box
    TRC        [  pixel] Top right corner of cleaning box
    POSITIVE   [       ] Minimum number of positive components at start
    KEEP       [       ] Keep cleaning after convergence
    MAJOR      [ arcsec] Clean beam major axis
    MINOR      [ arcsec] Clean beam minor axis
    ANGLE      [ degree] Position angle of clean beam
    BEAM_PATCH [  pixel] Size of cleaning beam ** not clear **

2 GAIN

    This is the gain of the subtraction loop.  It should typically be chosen
    in the range 0.05 and 0.3.  Higher values give faster convergence, while
    lower values give a better restitution of the extended structure. A sen-
    sible default is 0.2.

2 NITER

    This is the maximum number of components the program will accept to sub-
    tract.  Once it has been reached, the  program  starts  the  restoration
    phase.

2 FRES

    This  is the minimal fraction of the peak flux in the dirty map that the
    program  will  consider  as  significant.   Alternatively,  an  absolute
    threshold can be specified using ARES.  Once this level has been reached
    the program stops subtracting, and starts the restoration  phase.   This
    parameter is normalized to 1 (neither in % nor in db).  It should usual-
    ly be of the order of magnitude of the inverse of the  expected  dynamic
    range of the intensity.

2 ARES

    This is the minimal flux in the dirty map that the program will consider
    as significant.  Alternatively, the threshold  can  be  specified  as  a
    fraction  of the peak flux using FRES.  Once this level has been reached
    the program stops subtracting, and starts the  restoration  phase.   The
    unit for this parameter is the map unit (Typically Jy/Beam).  The param-
    eter should usually be of the order of magnitude of the  expected  noise
    in the clean map.

2 BLC

    These  are  the  (pixel)  coordinates  of  the Bottom Left Corner of the
    cleaning box.  The actual cleaning support will be the  intersection  of
    the specified window with the inner quarter of the map and with any user
    defined polygon.

2 TRC

    These are the (pixel) coordinates of the Top Right Corner of the  clean-
    ing  box.   The  actual  cleaning window will be the intersection of the
    specified window with the inner quarter of the map and with any user de-
    fined polygon.

2 POSITIVE

    The  minimum  number of positive components before negative ones are se-
    lected.

2 KEEP

    This is a logical flag to keep cleaning after an approximate convergence
    has been reached.  It should usually be set to .TRUE., except may be for
    the SIMPLE method.

2 MAJOR

    This is the major axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 MINOR

    This is the minor axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 ANGLE

    This is the position angle (from North towards East, i.e. anticlockwise)
    of  the  major  axis of the Gaussian restoring beam (in degrees).  If 0,
    the program will fit a Gaussian to the dirty beam. We strongly  discour-
    age to change the default value of 0.

2 BEAM_PATCH

    The  dirty  beam  patch to be used for the minor cycles in CLARK and MRC
    method.  It should be large enough to avoid doing too many major cycles,
    but  has  practically  no  influence on the result.  This size should be
    specified in pixel units.  Reasonable values are between  N/8  and  N/4,
    where N is the number of map pixels in the same dimension.  If set to N,
    the CLARK algorithm becomes identical to the SIMPLE algorithm.

1 DUMP
        [CLEAN\]DUMP [U]

    Dump on screen the control parameters of the different CLEAN  deconvolu-
    tion algorithms, mainly for debugging purpose. "DUMP U" dumps the param-
    eters as input by the user while "DUMP" dumps the parameters really used
    and/or modified by the deconvolution algorithm.

1 FIT
        [CLEAN\]FIT [Field]

    Fit  the  dirty  beam to obtain the clean beam parameters.  This is done
    automatically by all CLEAN algorithm when needed. Clean beam  parameters
    can also be specified by the users, by setting the variables MAJOR_AXIS,
    MINOR_AXIS and ANGLE to values other than their default values  (0,0,0).
    In  this case, no automatic fit will be performed.  We strongly discour-
    age the use of those variables.

    In mosaic mode, you can specify on which field the fit has to  be  made,
    using the first argument.

1 FLUX_SCALE
        [CLEAN\]FLUX Find|Apply|List|Calibrate [VarName]

    A  set  of  commands to check flux calibration on a day to day basis.  A
    supervising procedure, check_flux.map, allows  self-calibration  of  the
    flux  by using as intermediate model a table generated by the Clean Com-
    ponent list.

    FLUX FIND DateTolerance
    determines, by linear regression, the best scaling factor to match  date
    by date the UV data set with the MODEL data set. Dates are assumed iden-
    tical if separated by less than DateTolerance

    FLUX APPLY VarName
    apply previously determined flux scale factors to the  MODEL  data  set,
    previously read by READ MODEL.  This is in general used only in an iter-
    ative search way, e.g. by procedure check_flux. The  resulting  UV  data
    set is loaded into the specified VarName SIC variable.

    FLUX LIST
    print out dates, baselines and determined flux factors

    FLUX CALIBRATE
    apply  previously determined flux scale factors to the UV data set. This
    may then be written using command WRITE UV .


1 HOGBOM
        [CLEAN\]HOGBOM [FirstPlane LastPlane] [/FLUX Fmin Fmax]

    The simplest CLEAN algorithm, originally developed by Hogbom. In  mosaic
    mode  (See  command  MOSAIC), a mosaic clean is performed.  Rings and or
    strips may appear on extended sources. It is slower  than  CLARK  for  a
    single  field  but  maybe  faster  for a mosaic. It is extremely robust.
    Cleaning can be interrupted by pressing C at any time.

    Clean the specified plane interval (default:  Planes  between  variables
    FIRST  and  LAST).  The cumulative, already cleaned flux is displayed in
    real time in an additional window while cleaning goes on when the  /FLUX
    option  is present. Parameters of the /FLUX option are then used to give
    the flux limits for this display.

    The user can control the algorithm  through  SIC  variables.  Values  of
    those variables can be checked through either "INPUT UV_MAP|CLEAN|UVALL"
    or "EXAMINE
     VARIABLE". New values can be given using "LET VARIABLE value". For ease
    of  use, and whenever it is possible, a sensible value of each parameter
    will automatically be computed from the context if the value of the cor-
    responding  variable  is  set  to its default value, i.e. zero value and
    empty string. A few variables are initialized to "reasonable" values.

    GAIN       [       ] Loop gain
    NITER      [       ] Maximum number of clean components
    FRES       [      %] Maximum value of residual (Fraction of peak)
    ARES       [Jy/Beam] Maximum value of residual (Absolute)
    BLC        [  pixel] Bottom left corner of cleaning box
    TRC        [  pixel] Top right corner of cleaning box
    POSITIVE   [       ] Minimum number of positive components at start
    KEEP       [       ] Keep cleaning after convergence
    MAJOR      [ arcsec] Clean beam major axis
    MINOR      [ arcsec] Clean beam minor axis
    ANGLE      [ degree] Position angle of clean beam
    BEAM_PATCH [  pixel] Size of cleaning beam ** not clear **

2 GAIN

    This is the gain of the subtraction loop.  It should typically be chosen
    in the range 0.05 and 0.3.  Higher values give faster convergence, while
    lower values give a better restitution of the extended structure. A sen-
    sible default is 0.2.

2 NITER

    This is the maximum number of components the program will accept to sub-
    tract.  Once it has been reached, the  program  starts  the  restoration
    phase.

2 FRES

    This  is the minimal fraction of the peak flux in the dirty map that the
    program  will  consider  as  significant.   Alternatively,  an  absolute
    threshold can be specified using ARES.  Once this level has been reached
    the program stops subtracting, and starts the restoration  phase.   This
    parameter is normalized to 1 (neither in % nor in db).  It should usual-
    ly be of the order of magnitude of the inverse of the  expected  dynamic
    range of the intensity.

2 ARES

    This is the minimal flux in the dirty map that the program will consider
    as significant.  Alternatively, the threshold  can  be  specified  as  a
    fraction  of the peak flux using FRES.  Once this level has been reached
    the program stops subtracting, and starts the  restoration  phase.   The
    unit for this parameter is the map unit (Typically Jy/Beam).  The param-
    eter should usually be of the order of magnitude of the  expected  noise
    in the clean map.

2 BLC

    These  are  the  (pixel)  coordinates  of  the Bottom Left Corner of the
    cleaning box.  The actual cleaning support will be the  intersection  of
    the specified window with the inner quarter of the map and with any user
    defined polygon.

2 TRC

    These are the (pixel) coordinates of the Top Right Corner of the  clean-
    ing  box.   The  actual  cleaning window will be the intersection of the
    specified window with the inner quarter of the map and with any user de-
    fined polygon.

2 POSITIVE

    The  minimum  number of positive components before negative ones are se-
    lected.

2 KEEP

    This is a logical flag to keep cleaning after an approximate convergence
    has been reached.  It should usually be set to .TRUE., except may be for
    the SIMPLE method.

2 MAJOR

    This is the major axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 MINOR

    This is the minor axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 ANGLE

    This is the position angle (from North towards East, i.e. anticlockwise)
    of  the  major  axis of the Gaussian restoring beam (in degrees).  If 0,
    the program will fit a Gaussian to the dirty beam. We strongly  discour-
    age to change the default value of 0.

2 BEAM_PATCH

    The  dirty  beam  patch to be used for the minor cycles in CLARK and MRC
    method.  It should be large enough to avoid doing too many major cycles,
    but  has  practically  no  influence on the result.  This size should be
    specified in pixel units.  Reasonable values are between  N/8  and  N/4,
    where N is the number of map pixels in the same dimension.  If set to N,
    the CLARK algorithm becomes identical to the SIMPLE algorithm.

1 LOAD
        [CLEAN\]LOAD Buffer

    Load the internal Buffer (CLEAN, DIRTY, RESIDUAL and BEAM) into the  SIC
    variable  named  W  for future used with standard GREG commands. Used in
    particular by the procedure GO PLOT, and by command SHOW.

1 MODIFY
        [CLEAN\]MODIFY Frequency|Velocity Value

        MODIFY Frequency Value
    Modify the rest frequency and recompute the velocity scale  accordingly.
    Value is the new rest frequency in MHz

        MODIFY Velocity Value
    Modify  the  source  velocity and recompute the rest frequency scale ac-
    cordingly Value is the new velocity in km/s.

1 MOSAIC
        [CLEAN\]MOSAIC [On|Off]

    Turn on or off the mosaic mode (default: On). Note that a  READ  PRIMARY
    command  automatically  switches  on the mosaic mode. The program prompt
    changes to inform the user.

1 MRC
        [CLEAN\]MRC [FirstPlane LastPlane] [/PLOT Clean|Residu] [/FLUX  Fmin
    Fmax] [/QUERY]

    Perform  a  Multi-Resolution CLEAN on the current dirty image.  MRC does
    not support mosaics for theoretical reasons.

    Clean the specified plane interval (default:  planes  between  variables
    FIRST  and  LAST).  If  option /PLOT is given, a display of the CLEAN or
    RESIDUAL map will be shown at each major cycle, depending on  the  argu-
    ment  (default:  Residual).  The  user will be prompted for continuation
    when the /QUERY option is present. The cumulative, already cleaned  flux
    is displayed in real time in an additional window while cleaning goes on
    when the /FLUX option is present. Parameters of  the  /FLUX  option  are
    then  used to give the flux limits for this display. A summary plot with
    the Difference, Smooth, and total CLEANed maps is also displayed.

    The user can control the algorithm  through  SIC  variables.  Values  of
    those variables can be checked through either "INPUT UV_MAP|CLEAN|UVALL"
    or "EXAMINE
     VARIABLE". New values can be given using "LET VARIABLE value". For ease
    of  use, and whenever it is possible, a sensible value of each parameter
    will automatically be computed from the context if the value of the cor-
    responding  variable  is  set  to its default value, i.e. zero value and
    empty string. A few variables are initialized to "reasonable" values.

    GAIN       [       ] Loop gain
    NITER      [       ] Maximum number of clean components
    FRES       [      %] Maximum value of residual (Fraction of peak)
    ARES       [Jy/Beam] Maximum value of residual (Absolute)
    BLC        [  pixel] Bottom left corner of cleaning box
    TRC        [  pixel] Top right corner of cleaning box
    POSITIVE   [       ] Minimum number of positive components at start
    KEEP       [       ] Keep cleaning after convergence
    MAJOR      [ arcsec] Clean beam major axis
    MINOR      [ arcsec] Clean beam minor axis
    ANGLE      [ degree] Position angle of clean beam
    BEAM_PATCH [  pixel] Size of cleaning beam ** not clear **
    RATIO      [       ] Smoothing factor

2 GAIN

    This is the gain of the subtraction loop.  It should typically be chosen
    in the range 0.05 and 0.3.  Higher values give faster convergence, while
    lower values give a better restitution of the extended structure. A sen-
    sible default is 0.2.

2 NITER

    This is the maximum number of components the program will accept to sub-
    tract.  Once it has been reached, the  program  starts  the  restoration
    phase.

2 FRES

    This  is the minimal fraction of the peak flux in the dirty map that the
    program  will  consider  as  significant.   Alternatively,  an  absolute
    threshold can be specified using ARES.  Once this level has been reached
    the program stops subtracting, and starts the restoration  phase.   This
    parameter is normalized to 1 (neither in % nor in db).  It should usual-
    ly be of the order of magnitude of the inverse of the  expected  dynamic
    range of the intensity.

2 ARES

    This is the minimal flux in the dirty map that the program will consider
    as significant.  Alternatively, the threshold  can  be  specified  as  a
    fraction  of the peak flux using FRES.  Once this level has been reached
    the program stops subtracting, and starts the  restoration  phase.   The
    unit for this parameter is the map unit (Typically Jy/Beam).  The param-
    eter should usually be of the order of magnitude of the  expected  noise
    in the clean map.

2 BLC

    These  are  the  (pixel)  coordinates  of  the Bottom Left Corner of the
    cleaning box.  The actual cleaning support will be the  intersection  of
    the specified window with the inner quarter of the map and with any user
    defined polygon.

2 TRC

    These are the (pixel) coordinates of the Top Right Corner of the  clean-
    ing  box.   The  actual  cleaning window will be the intersection of the
    specified window with the inner quarter of the map and with any user de-
    fined polygon.

2 POSITIVE

    The  minimum  number of positive components before negative ones are se-
    lected.

2 KEEP

    This is a logical flag to keep cleaning after an approximate convergence
    has been reached.  It should usually be set to .TRUE., except may be for
    the SIMPLE method.

2 MAJOR

    This is the major axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 MINOR

    This is the minor axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 ANGLE

    This is the position angle (from North towards East, i.e. anticlockwise)
    of  the  major  axis of the Gaussian restoring beam (in degrees).  If 0,
    the program will fit a Gaussian to the dirty beam. We strongly  discour-
    age to change the default value of 0.

2 BEAM_PATCH

    The  dirty  beam  patch to be used for the minor cycles in CLARK and MRC
    method.  It should be large enough to avoid doing too many major cycles,
    but  has  practically  no  influence on the result.  This size should be
    specified in pixel units.  Reasonable values are between  N/8  and  N/4,
    where N is the number of map pixels in the same dimension.  If set to N,
    the CLARK algorithm becomes identical to the SIMPLE algorithm.

2 RATIO

    Used smoothing factor, which must be a power of 2. The default is  esti-
    mated from the image size.

1 MULTI
        [CLEAN\]MULTI [FirstPlane LastPlane] [/FLUX Fmin Fmax]

    Multiscale CLEAN algorithm.

    Clean  the  specified  plane interval (default: Planes between variables
    FIRST and LAST). The cumulative, already cleaned flux  is  displayed  in
    real  time in an additional window while cleaning goes on when the /FLUX
    option is present. Parameters of the /FLUX option are then used to  give
    the flux limits for this display.

    MULTI does not yet work on mosaics.

    The  user  can  control  the  algorithm through SIC variables. Values of
    those variables can be checked through either "INPUT UV_MAP|CLEAN|UVALL"
    or "EXAMINE
     VARIABLE". New values can be given using "LET VARIABLE value". For ease
    of use, and whenever it is possible, a sensible value of each  parameter
    will automatically be computed from the context if the value of the cor-
    responding variable is set to its default value,  i.e.  zero  value  and
    empty string. A few variables are initialized to "reasonable" values.

    GAIN       [       ] Loop gain
    NITER      [       ] Maximum number of clean components
    FRES       [      %] Maximum value of residual (Fraction of peak)
    ARES       [Jy/Beam] Maximum value of residual (Absolute)
    BLC        [  pixel] Bottom left corner of cleaning box
    TRC        [  pixel] Top right corner of cleaning box
    POSITIVE   [       ] Minimum number of positive components at start
    KEEP       [       ] Keep cleaning after convergence
    MAJOR      [ arcsec] Clean beam major axis
    MINOR      [ arcsec] Clean beam minor axis
    ANGLE      [ degree] Position angle of clean beam
    BEAM_PATCH [  pixel] Size of cleaning beam ** not clear **

2 GAIN

    This is the gain of the subtraction loop.  It should typically be chosen
    in the range 0.05 and 0.3.  Higher values give faster convergence, while
    lower values give a better restitution of the extended structure. A sen-
    sible default is 0.2.

2 NITER

    This is the maximum number of components the program will accept to sub-
    tract.   Once  it  has  been reached, the program starts the restoration
    phase.

2 FRES

    This is the minimal fraction of the peak flux in the dirty map that  the
    program  will  consider  as  significant.   Alternatively,  an  absolute
    threshold can be specified using ARES.  Once this level has been reached
    the  program  stops subtracting, and starts the restoration phase.  This
    parameter is normalized to 1 (neither in % nor in db).  It should usual-
    ly  be  of the order of magnitude of the inverse of the expected dynamic
    range of the intensity.

2 ARES

    This is the minimal flux in the dirty map that the program will consider
    as  significant.   Alternatively,  the  threshold  can be specified as a
    fraction of the peak flux using FRES.  Once this level has been  reached
    the  program  stops  subtracting, and starts the restoration phase.  The
    unit for this parameter is the map unit (Typically Jy/Beam).  The param-
    eter  should  usually be of the order of magnitude of the expected noise
    in the clean map.

2 BLC

    These are the (pixel) coordinates of  the  Bottom  Left  Corner  of  the
    cleaning  box.   The actual cleaning support will be the intersection of
    the specified window with the inner quarter of the map and with any user
    defined polygon.

2 TRC

    These  are the (pixel) coordinates of the Top Right Corner of the clean-
    ing box.  The actual cleaning window will be  the  intersection  of  the
    specified window with the inner quarter of the map and with any user de-
    fined polygon.

2 POSITIVE

    The minimum number of positive components before negative ones  are  se-
    lected.

2 KEEP

    This is a logical flag to keep cleaning after an approximate convergence
    has been reached.  It should usually be set to .TRUE., except may be for
    the SIMPLE method.

2 MAJOR

    This  is  the  major  axis  (FWHP)  in  user coordinates of the Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 MINOR

    This  is  the  minor  axis  (FWHP)  in  user coordinates of the Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 ANGLE

    This is the position angle (from North towards East, i.e. anticlockwise)
    of the major axis of the Gaussian restoring beam (in  degrees).   If  0,
    the  program will fit a Gaussian to the dirty beam. We strongly discour-
    age to change the default value of 0.

2 BEAM_PATCH

    The dirty beam patch to be used for the minor cycles in  CLARK  and  MRC
    method.  It should be large enough to avoid doing too many major cycles,
    but has practically no influence on the result.   This  size  should  be
    specified  in  pixel  units.  Reasonable values are between N/8 and N/4,
    where N is the number of map pixels in the same dimension.  If set to N,
    the CLARK algorithm becomes identical to the SIMPLE algorithm.

1 MX
        [CLEAN\]MX  [FirstPlane  LastPlane] [/PLOT Clean|Residu] [/FLUX Fmin
    Fmax] [/QUERY]

    Make and deconvolve maps starting from a UV table.  It  combines  UV_MAP
    and CLEAN in a single step.

    The mapping process is identical to UV_MAP.  It makes a map from UV data
    by griding the UV data using a convolving function, and then Fast Fouri-
    er  Transforming the individual channels.  However, MX always produces a
    single beam for all channels, thus neglecting frequency  change  between
    channels.   MX  enables to shift the map center and rotate the image, by
    shifting the phase tracking center and rotating the  UV  coordinates  of
    the input UV table.

    The  CLEAN  algorithm is similar to the CLARK method, but with major cy-
    cles operating directly on the ungridded UV table rather than in the im-
    age  plane. Accordingly, aliasing affects only of the residuals, not the
    clean components. It is thus more accurate but also slower than CLARK as
    it  asks  for the gridding step at each major cycle.  MX also shares the
    same limitation as CLARK on large sidelobes.

    The user can control the algorithm  through  SIC  variables.  Values  of
    those variables can be checked through either "INPUT UV_MAP|CLEAN|UVALL"
    or "EXAMINE
     VARIABLE". New values can be given using "LET VARIABLE value". For ease
    of  use, and whenever it is possible, a sensible value of each parameter
    will automatically be computed from the context if the value of the cor-
    responding  variable  is  set  to its default value, i.e. zero value and
    empty string. A few variables are initialized to "reasonable" values.

    NAME        [       ]  Label of the dirty image and beam plots
    UV_TAPER    [m,m,deg]  UV-apodization by convolution with a Gaussian
    WEIGHT_MODE [       ]  Weighting mode (NA|UN)
    UV_CELL     [m, ??  ]  UV cell size and threshold for Robust weighting
    MAP_FIELD   [ arcsec]  Map field of view
    MAP_CELL    [ arcsec]  Map cell size
    MAP_SIZE    [ pixels]  Map size in pixels (if MAP_FIELD is zero)
    MCOL        [       ]  First and Last channel to map
    WCOL        [       ]  Channel from which the weights are taken
    CONVOLUTION [       ]  Convolution function (5)
    UV_SHIFT    [       ]  Change the map phase center or map orientation?
    MAP_RA      [       ]  RA of map phase center
    MAP_DEC     [       ]  Dec of map phase center
    MAP_ANGLE   [    deg]  Map position angle
    GAIN       [       ] Loop gain
    NITER      [       ] Maximum number of clean components
    FRES       [      %] Maximum value of residual (Fraction of peak)
    ARES       [Jy/Beam] Maximum value of residual (Absolute)
    BLC        [  pixel] Bottom left corner of cleaning box
    TRC        [  pixel] Top right corner of cleaning box
    POSITIVE   [       ] Minimum number of positive components at start
    KEEP       [       ] Keep cleaning after convergence
    MAJOR      [ arcsec] Clean beam major axis
    MINOR      [ arcsec] Clean beam minor axis
    ANGLE      [ degree] Position angle of clean beam
    BEAM_PATCH [  pixel] Size of cleaning beam ** not clear **
2 NAME

    The name to be printed on the right side of the dirty  image  and  dirty
    beam plots (with extensions .LMV and .BEAM).

2 UV_TAPER

    Parameters  of the tapering function (Gaussian): major axis at 1/e level
    [m], minor axis at 1/e level [m], and position angle [deg].

2 WEIGHT_MODE

    Weighting mode: Natural (optimum in  terms  of  sensitivity)  or  robust
    (usually  lower sidelobes) weighting. Use LET WEIGHT_MODE NA for natural
    or LET WEIGHT_MODE UN for robust weighting.

    The actual weighting methods implemented are Natural and Robust  weight-
    ing. Robust weighting gives the natural weight to UV cells whose natural
    weight is lower than a given threshold.  In  contrast,  if  the  natural
    weight  of  the UV cell is larger than this threshold, the weight is set
    to this (uniform) threshold. The UV cell size and  the  threshold  value
    are contained in the UV_CELL variable.

2 UV_CELL

    UV_CELL[1]  :  UV  cell size for robust weighting [m].  Should be of the
    order of half the dish diameter (7.5 m for PdBI), or smaller.

    UV_CELL[2] : Threshold for robust weighting. Default value is 1. 0 means
    natural weighting and infinite would mean uniform weighting. Use UV_STAT
    WEIGHT to choose an educated value.

2 MAP_CELL

    The map pixel size [arcsec]. It is recommended to use  identical  values
    in  X  and Y.  A sampling of at least 3 pixel per beam is recommended to
    ease the deconvolution. Enter 0,0 to let the task find the best  values.

2 MAP_FIELD

    Field  of  view  in  X and Y in arcsec.  The field of view MAP_FIELD has
    precedence over the map size MAP_SIZE when both ar non-zero.

2 MAP_SIZE

    Number of pixels in X and Y. It should preferentially be a power of two,
    (although    this   is   not   strictly   required)   to   fasten   FFT.
    MAP_SIZE*MAP_CELL should be at least twice the size of the field-of-view
    (primary  beam  size  for  a single field). Enter 0,0 to let the command
    find a sensible map size.

2 MCOL

    First and Last channel to image.  Values  of  0  mean  imaging  all  the
    planes.

2 WCOL

    The  channel from which the weight should be taken.  WCOL set to 0 means
    using the central channel.

2 CONVOLUTION

    Select the desired convolution function for gridding  in  the  UV  plane
    Choices are
            0    Default (currently 5)
            1    Boxcar
            2    Gaussian
            3    Sin(x)/x
            4    Gaussian * Sin(x)/x
            5    Spheroidal
    Spheroidal  functions  is  the optimal choice. So we strongly discourage
    use of any other convolution function.

2 UV_SHIFT

    Logical variable indicating whether map center (i.e. phase tracking cen-
    ter) or orientation should be changed.

2 MAP_RA

    New Right Ascension of map phase center. Used only if UV_SHIFT is YES.

2 MAP_DEC

    New Declination of map phase center. Used only if UV_SHIFT is YES.

2 MAP_ANGLE

    Position  Angle of the direction which will become the apparent North in
    the map. Used only if UV_SHIFT is YES.

2 GAIN

    This is the gain of the subtraction loop.  It should typically be chosen
    in the range 0.05 and 0.3.  Higher values give faster convergence, while
    lower values give a better restitution of the extended structure. A sen-
    sible default is 0.2.

2 NITER

    This is the maximum number of components the program will accept to sub-
    tract.  Once it has been reached, the  program  starts  the  restoration
    phase.

2 FRES

    This  is the minimal fraction of the peak flux in the dirty map that the
    program  will  consider  as  significant.   Alternatively,  an  absolute
    threshold can be specified using ARES.  Once this level has been reached
    the program stops subtracting, and starts the restoration  phase.   This
    parameter is normalized to 1 (neither in % nor in db).  It should usual-
    ly be of the order of magnitude of the inverse of the  expected  dynamic
    range of the intensity.

2 ARES

    This is the minimal flux in the dirty map that the program will consider
    as significant.  Alternatively, the threshold  can  be  specified  as  a
    fraction  of the peak flux using FRES.  Once this level has been reached
    the program stops subtracting, and starts the  restoration  phase.   The
    unit for this parameter is the map unit (Typically Jy/Beam).  The param-
    eter should usually be of the order of magnitude of the  expected  noise
    in the clean map.

2 BLC

    These  are  the  (pixel)  coordinates  of  the Bottom Left Corner of the
    cleaning box.  The actual cleaning support will be the  intersection  of
    the specified window with the inner quarter of the map and with any user
    defined polygon.

2 TRC

    These are the (pixel) coordinates of the Top Right Corner of the  clean-
    ing  box.   The  actual  cleaning window will be the intersection of the
    specified window with the inner quarter of the map and with any user de-
    fined polygon.

2 POSITIVE

    The  minimum  number of positive components before negative ones are se-
    lected.

2 KEEP

    This is a logical flag to keep cleaning after an approximate convergence
    has been reached.  It should usually be set to .TRUE., except may be for
    the SIMPLE method.

2 MAJOR

    This is the major axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 MINOR

    This is the minor axis  (FWHP)  in  user  coordinates  of  the  Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 ANGLE

    This is the position angle (from North towards East, i.e. anticlockwise)
    of  the  major  axis of the Gaussian restoring beam (in degrees).  If 0,
    the program will fit a Gaussian to the dirty beam. We strongly  discour-
    age to change the default value of 0.

2 BEAM_PATCH

    The  dirty  beam  patch to be used for the minor cycles in CLARK and MRC
    method.  It should be large enough to avoid doing too many major cycles,
    but  has  practically  no  influence on the result.  This size should be
    specified in pixel units.  Reasonable values are between  N/8  and  N/4,
    where N is the number of map pixels in the same dimension.  If set to N,
    the CLARK algorithm becomes identical to the SIMPLE algorithm.

1 READ
        [CLEAN\]READ Buffer File [/PLANE First Last] [/COMPACT]

    Read the specified internal buffer (UV,  MODEL,  BEAM,  PRIMARY,  DIRTY,
    CLEAN, MASK, CCT) from input File. Default extension are .uvt for UV and
    MODEL, and then .beam, .lobe, .lmv, channels can be specified using  op-
    tion /PLANE (valid also for UV tables).

    The MODEL UV table is for use in conjunction with command FLUX.

    The  /COMPACT  option  is  used to load the ACA-specific internal buffer
    used in the ALMA joint deconvolution method.

1 SDI
        [CLEAN\]SDI [FirstPlane LastPlane] [/PLOT Clean|Residu] [/FLUX  Fmin
    Fmax] [/QUERY]

    Perform a Steer-Dewdney-Ito CLEAN. This clean method selects an ensemble
    of clean components and remove them at once using FFTs.  It  works  best
    for  extended  sources  and  UV coverages with short spacings. In such a
    case, it may avoid the "ringing" features which appear using  the  CLARK
    or  HOGBOM  techniques.  In  mosaic  mode (see command MOSAIC), a mosaic
    clean is performed.

    Clean the specified plane interval (default:  planes  between  variables
    FIRST  and  LAST).  If  option /PLOT is given, a display of the CLEAN or
    RESIDUAL map will be shown at each major cycle, depending on  the  argu-
    ment  (default:  Residual).  The  user will be prompted for continuation
    when the /QUERY option is present. The cumulative, already cleaned  flux
    is displayed in real time in an additional window while cleaning goes on
    when the /FLUX option is present. Parameters of  the  /FLUX  option  are
    then used to give the flux limits for this display.

    The  user  can  control  the  algorithm through SIC variables. Values of
    those variables can be checked through either "INPUT UV_MAP|CLEAN|UVALL"
    or "EXAMINE
     VARIABLE". New values can be given using "LET VARIABLE value". For ease
    of use, and whenever it is possible, a sensible value of each  parameter
    will automatically be computed from the context if the value of the cor-
    responding variable is set to its default value,  i.e.  zero  value  and
    empty string. A few variables are initialized to "reasonable" values.
    GAIN       [       ] Loop gain
    NITER      [       ] Maximum number of clean components
    FRES       [      %] Maximum value of residual (Fraction of peak)
    ARES       [Jy/Beam] Maximum value of residual (Absolute)
    BLC        [  pixel] Bottom left corner of cleaning box
    TRC        [  pixel] Top right corner of cleaning box
    POSITIVE   [       ] Minimum number of positive components at start
    KEEP       [       ] Keep cleaning after convergence
    MAJOR      [ arcsec] Clean beam major axis
    MINOR      [ arcsec] Clean beam minor axis
    ANGLE      [ degree] Position angle of clean beam
    BEAM_PATCH [  pixel] Size of cleaning beam ** not clear **

2 GAIN

    This is the gain of the subtraction loop.  It should typically be chosen
    in the range 0.05 and 0.3.  Higher values give faster convergence, while
    lower values give a better restitution of the extended structure. A sen-
    sible default is 0.2.

2 NITER

    This is the maximum number of components the program will accept to sub-
    tract.   Once  it  has  been reached, the program starts the restoration
    phase.

2 FRES

    This is the minimal fraction of the peak flux in the dirty map that  the
    program  will  consider  as  significant.   Alternatively,  an  absolute
    threshold can be specified using ARES.  Once this level has been reached
    the  program  stops subtracting, and starts the restoration phase.  This
    parameter is normalized to 1 (neither in % nor in db).  It should usual-
    ly  be  of the order of magnitude of the inverse of the expected dynamic
    range of the intensity.

2 ARES

    This is the minimal flux in the dirty map that the program will consider
    as  significant.   Alternatively,  the  threshold  can be specified as a
    fraction of the peak flux using FRES.  Once this level has been  reached
    the  program  stops  subtracting, and starts the restoration phase.  The
    unit for this parameter is the map unit (Typically Jy/Beam).  The param-
    eter  should  usually be of the order of magnitude of the expected noise
    in the clean map.

2 BLC

    These are the (pixel) coordinates of  the  Bottom  Left  Corner  of  the
    cleaning  box.   The actual cleaning support will be the intersection of
    the specified window with the inner quarter of the map and with any user
    defined polygon.

2 TRC

    These  are the (pixel) coordinates of the Top Right Corner of the clean-
    ing box.  The actual cleaning window will be  the  intersection  of  the
    specified window with the inner quarter of the map and with any user de-
    fined polygon.

2 POSITIVE

    The minimum number of positive components before negative ones  are  se-
    lected.

2 KEEP

    This is a logical flag to keep cleaning after an approximate convergence
    has been reached.  It should usually be set to .TRUE., except may be for
    the SIMPLE method.

2 MAJOR

    This  is  the  major  axis  (FWHP)  in  user coordinates of the Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 MINOR

    This  is  the  minor  axis  (FWHP)  in  user coordinates of the Gaussian
    restoring beam. If 0, the program will fit a Gaussian to the dirty beam.
    We strongly discourage to change the default value of 0.

2 ANGLE

    This is the position angle (from North towards East, i.e. anticlockwise)
    of the major axis of the Gaussian restoring beam (in  degrees).   If  0,
    the  program will fit a Gaussian to the dirty beam. We strongly discour-
    age to change the default value of 0.

2 BEAM_PATCH

    The dirty beam patch to be used for the minor cycles in  CLARK  and  MRC
    method.  It should be large enough to avoid doing too many major cycles,
    but has practically no influence on the result.   This  size  should  be
    specified  in  pixel  units.  Reasonable values are between N/8 and N/4,
    where N is the number of map pixels in the same dimension.  If set to N,
    the CLARK algorithm becomes identical to the SIMPLE algorithm.

1 SHOW
        [CLEAN\]SHOW Variable [First [Last]]

    where
        RESIDUAL, CLEAN, NEAT, NMR, SUPPORT, MASK and CCT)
        are optional arguments to restrict the range of channels to be plot-
    ted (default FIRST and LAST variables)

    The buffer is loaded in SIC Header variable W, and then displayed  using
    the appropriate procedure
      p_plot_w
      p_cct_w for Clean Component Tables
      p_uvplot for UV data
    Command VIEW offers a different style of display for cubes.

    The  UV data in the internal buffer is the one loaded by command READ UV
    File and optionally resampled by UV_RESAMPLE, UV_COMPRESS or transformed
    by UV_CONT. Flagged UV data  will appear in a different color.

    GO  PLOT  and GO UVSHOW offer more sophisticated alternative, but taking
    data from files instead of the internal buffers. They may overwrite  the
    internal buffers.

2 GO_PLOT
        GO  PLOT provides a somewhat different plotting mechanism, using the
    corresponding disk files rather than the internal buffers.
            GO PLOT Variable [First [Last]]
    which will plot channels of the specified data set.  First (default:  0)
    and  Last  (default:  First) are optional arguments indicating the first
    and last channel to be displayed. If not specified the  variables  FIRST
    and LAST are used.

    Most  aspects  of  the display are controlled through the same SIC vari-
    ables as the ones used by the "GO BIT|MAP|LMV" commands. Detailed infor-
    mation about those variables is found through the "INPUT LMV" command.

2 GO_UVSHOW
        GO UVSHOW

    Display  UV data from the 'name'.uvt file. Control parameters are avail-
    able as SIC variables. Use command INPUT UVSHOW to check them.

1 STATISTIC
        [CLEAN\]STATISTIC [Clean|Dirty|Residu] [Plane] [/WHOLE]

    Compute some basic statistics (min, max, mean, rms,...) on the specified
    buffer (default: Clean) and plane (default: variable FIRST). The current
    polygon (see command SUPPORT) is used to define the area  on  which  the
    pixels  are  to  be  taken  into  account,  except when option /WHOLE is
    present: The whole image is then considered.

1 SUPPORT
        [CLEAN\]SUPPORT [Polygon] [/CURSOR] [/PLOT] [/MASK] [/RESET]

    Define the support inside which to search for CLEAN components. The sup-
    port  can  be  defined through a mask or a polygon, depending on the op-
    tions selected.

    Withouth /MASK or /RESET option, SUPPORT calls command POLYGON  of  GREG
    to  load  a polygon. A polygon stored in a  file can be load as support.
    The /PLOT option can then be used to plot it.

2 /CURSOR
        [CLEAN\]SUPPORT /CURSOR          With option /CURSOR, it  calls  the
    interactive cursor to define the polygon summits.  Type any key to go to
    next summit, D to correct the last one and type E  to  end  the  polygon
    definition.  The last polygon side will then appear. The polygon defini-
    tion may be aborted by typing Q. For X11 displays, you may use the mouse
    buttons  for  the  commands.   The left mouse button draws a vertex, the
    middle mouse button deletes the last vertex, and the right mouse  button
    ends the polygon definition.

2 /RESET
        [CLEAN\]SUPPORT /RESET

    Reset any support to default.

2 /MASK
        [CLEAN\]SUPPORT /MASK

    Use  the  mask  defined by READ MASK as the clean support. This does not
    suppress the current polygon: it can be re-instated by SUPPORT /PLOT.
     READ MASK performs an implicit SUPPORT /MASK command.

2 /PLOT
        [CLEAN\]SUPPORT [filename] /PLOT

    Plot the current (or specified) polygon and use it  to  define  the  the
    clean support. This does not suppress the current mask: it can be re-in-
    stated by SUPPORT /MASK.


1 UV_BASELINE
        [CLEAN\]UV_BASELINE [Degree]  [/CHANNELS  Channel_List]  [/FREQUENCY
    List Of Frequencies] [/WIDTH Width]

    Subtract a continuum from a line UV data set, by fitting  a baseline for
    each visibility.  The channels to be ignored in this process  (i.e.  the
    ones  including the line emission) can be specified either by the /CHAN-
    NEL option or by the /FREQUENCY and /WIDTH options.

2 /CHANNELS
        [CLEAN\]UV_BASELINE /CHANNELS Channel_List

    Channel_List must be a 1-D SIC variable containing the list of  channels
    to filter out.

2 /FREQUENCY
        [CLEAN\]UV_BASELINE /FREQUENCY F1 [... [Fn]] [/WIDTH Width]

    Specify  around  which frequencies the line emission should be filtered.
    Frequencies F1 to Fn must be in MHz. The width (in MHz) of the filtering
    window  around every frequency can be set by option /WIDTH.  The default
    width is the current channel width.

    Tip: it can be convenient to have a list of SIC variables containing the
    frequencies of the most intense spectral lines, e.g.
            HCO10 = 89188.52

2 /WIDTH
        [CLEAN\]UV_BASELINE /FREQUENCY F1 [... [Fn]] /WIDTH Width

    Specify the width (in MHz) of the window around every frequency given in
    the /FREQUENCY option.  The default width is the current channel  width.

1 UV_COMPRESS
        [CLEAN\]UV_COMPRESS Nc

    Resample  the  UV  data loaded by READ UV by averaging NC adjacent chan-
    nels. All other UV commands except UV_RESAMPLE work on  the  "Resampled"
    UV table.

    The  "Resampled"  UV  table is a simple copy of the original one after a
    READ UV command, or after a UV_RESAMPLE or UV_COMPRESS commands  without
    arguments.



1 UV_CONT
        [CLEAN\]UV_CONT Naver [First Last]

    Transform  the  (presumably spectral line) UV data set loaded by READ UV
    into a "continuum" data set.

    The transformation selects line channels from  First  to  Last,  average
    them by groups of Naver contiguous channels, and concatenate the result-
    ing visibilities into a "continuum" UV table.

    For each of the (First-Last+1)/Naver channels, and for all visibilities,
    the  U  and  V coordinates are rescaled to the mean observing frequency,
    and the resulting (single-channel) visibilities  are  concatenated  into
    the  "continuum"  UV data set. The continuum dataset becomes the current
    UV data. Flagged channels are ignored: this allows to mask channels con-
    taining spectral lines (see UV_FILTER).

    Default  for  First  and Last is 0 0, meaning all channels are selected.
    Negative value for Last indicate an offset from end  channel  (i.e.  -20
    means ignore the last 20 channels).

1 UV_FILTER
        [CLEAN\]UV_FILTER  [/ZERO] [/CHANNELS Channel_List] [/FREQUENCY List
    Of Frequencies] [/WIDTH Width]

    "Filter" line emission, by  flagging  the  corresponding  channels.  The
    channels  can be specified either by the /CHANNEL option or by the /FRE-
    QUENCY and /WIDTH options.

    By default, channels to be filtered are flagged (weights becoming  nega-
    tive).  Option /ZERO can be used to erase them: weights and visibilities
    are set to zero, see HELP UV_FILTER /ZERO.

2 /CHANNELS
        [CLEAN\]UV_FILTER [/ZERO] /CHANNELS Channel_List

    Channel_List must be a 1-D SIC variable containing the list of  channels
    to filter out.

2 /FREQUENCY
        [CLEAN\]UV_FILTER [/ZERO] /FREQUENCY F1 [... [Fn]] [/WIDTH Width]

    Specify  around  which frequencies the line emission should be filtered.
    Frequencies F1 to Fn must be in MHz. The width (in MHz) of the filtering
    window  around every frequency can be set by option /WIDTH.  The default
    width is the current channel width.

    Tip: it can be convenient to have a list of SIC variables containing the
    frequencies of the most intense spectral lines, e.g.
            HCO10 = 89188.52

2 /WIDTH
        [CLEAN\]UV_FILTER [/ZERO] /FREQUENCY F1 [... [Fn]] /WIDTH Width

    Specify the width (in MHz) of the filtering window around every frequen-
    cy given in the /FREQUENCY option.  The default  width  is  the  current
    channel width.

2 /ZERO
        [CLEAN\]UV_FILTER /ZERO [/CHANNELS Channel_List] [/FREQUENCY F1 [...
    [Fn]] [/WIDTH Width]

    Erase filtered channels (set weight and  visibilities  to  zero)  rather
    than  simply  flagging  them (weight set to negative value). This can be
    more convenient for further display, but is not reversible.

    By default, channels to be filtered are flagged (weights becoming  nega-
    tive,  and  data can be unflagged by UV_FLAG).  Flagged channels are ig-
    nored in the averaging process, such as UV_RESAMPLE or UV_CONT. However,
    as  UV_MAP  (in general) uses only one channel to define the weights for
    all others, these flagged channels will nevertheless appear in  the  im-
    aged data cube.


1 UV_FLAG
        [CLEAN\]UV_FLAG [/RESET]

    Display  UV  data  and calls the cursor to interactively select a region
    where UV data will be flagged (sign of weight is reversed).  The  /RESET
    option is used to unflag the data. UV data flagged using command UV_FLAG
    can be saved on file with command WRITE UV  File.  Detailed  information
    about  the  display  control  of the UV data may be found in the UV_SHOW
    help.

    The user can control the algorithm through variables.  Values  of  those
    variables  can  be  checked  using "EXAMINE VARIABLE". New values can be
    given using "LET VARIABLE value".

    DATE_START  [    ] The date of the first data to be flagged
    UT_START    [    ] The UT time of the first data to be flagged
    DATE_END    [    ] The date of the last data to be flagged
    UT_END      [    ] The time of the last data to be flagged
    BASELINE    [    ] Baseline to flagged
    CHANNEL     [    ] Channel range to be flagged/unflagged
    FLAG        [    ] Flag or unflag the specified time range

    Subsequent mapping with UV_MAP will ignore flagged  data.  However,  for
    multi-channel  imaging, the weight column is (by default) taken from one
    channel, so that channel-based flagging will not be  recognized  in  the
    default mode, but only in the "One Beam per Channel" mode.

2 DATE_START

    The date (DD-MMM-YYYY) of the first data to be flagged.

2 UT_START

    The UT time (hh:mm:ss.ss) of the first data to be flagged.

2 DATE_END

    The date (DD-MMM-YYYY) of the last data to be flagged.

2 UT_END

    The time (hh:mm:ss.ss) of the last data to be flagged.

2 BASELINE

    Baseline (ALL, 12, 13, 23, ...) to flagged.

2 FLAG

    Flag (T) or unflag (F) the specified time range.

2 CHANNEL

    Channel range to be flagged/unflagged.

1 UV_MAP
        [CLEAN\]UV_MAP

    Compute  a  dirty  map  and  beam from a UV data. UV data must have been
    loaded from a UV table by command "READ UV File".

    The user can control the algorithm  through  SIC  variables.  Values  of
    those variables can be checked through either "INPUT UV_MAP|CLEAN|UVALL"
    or "EXAMINE
     VARIABLE". New values can be given using "LET VARIABLE value". For ease
    of  use, and whenever it is possible, a sensible value of each parameter
    will automatically be computed from the context if the value of the cor-
    responding  variable  is  set  to its default value, i.e. zero value and
    empty string. A few variables are initialized to "reasonable" values.

    NAME        [       ]  Label of the dirty image and beam plots
    UV_TAPER    [m,m,deg]  UV-apodization by convolution with a Gaussian
    WEIGHT_MODE [       ]  Weighting mode (NA|UN)
    UV_CELL     [m, ??  ]  UV cell size and threshold for Robust weighting
    MAP_FIELD   [ arcsec]  Map field of view
    MAP_CELL    [ arcsec]  Map cell size
    MAP_SIZE    [ pixels]  Map size in pixels (if MAP_FIELD is zero)
    MCOL        [       ]  First and Last channel to map
    WCOL        [       ]  Channel from which the weights are taken
    CONVOLUTION [       ]  Convolution function (5)
    UV_SHIFT    [       ]  Change the map phase center or map orientation?
    MAP_RA      [       ]  RA of map phase center
    MAP_DEC     [       ]  Dec of map phase center
    MAP_ANGLE   [    deg]  Map position angle
2 NAME

    The name to be printed on the right side of the dirty  image  and  dirty
    beam plots (with extensions .LMV and .BEAM).

2 UV_TAPER

    Parameters  of the tapering function (Gaussian): major axis at 1/e level
    [m], minor axis at 1/e level [m], and position angle [deg].

2 WEIGHT_MODE

    Weighting mode: Natural (optimum in  terms  of  sensitivity)  or  robust
    (usually  lower sidelobes) weighting. Use LET WEIGHT_MODE NA for natural
    or LET WEIGHT_MODE UN for robust weighting.

    The actual weighting methods implemented are Natural and Robust  weight-
    ing. Robust weighting gives the natural weight to UV cells whose natural
    weight is lower than a given threshold.  In  contrast,  if  the  natural
    weight  of  the UV cell is larger than this threshold, the weight is set
    to this (uniform) threshold. The UV cell size and  the  threshold  value
    are contained in the UV_CELL variable.

2 UV_CELL

    UV_CELL[1]  :  UV  cell size for robust weighting [m].  Should be of the
    order of half the dish diameter (7.5 m for PdBI), or smaller.

    UV_CELL[2] : Threshold for robust weighting. Default value is 1. 0 means
    natural weighting and infinite would mean uniform weighting. Use UV_STAT
    WEIGHT to choose an educated value.

2 MAP_CELL

    The map pixel size [arcsec]. It is recommended to use  identical  values
    in  X  and Y.  A sampling of at least 3 pixel per beam is recommended to
    ease the deconvolution. Enter 0,0 to let the task find the best  values.

2 MAP_FIELD

    Field  of  view  in  X and Y in arcsec.  The field of view MAP_FIELD has
    precedence over the map size MAP_SIZE when both ar non-zero.

2 MAP_SIZE

    Number of pixels in X and Y. It should preferentially be a power of two,
    (although    this   is   not   strictly   required)   to   fasten   FFT.
    MAP_SIZE*MAP_CELL should be at least twice the size of the field-of-view
    (primary  beam  size  for  a single field). Enter 0,0 to let the command
    find a sensible map size.

2 MCOL

    First and Last channel to image.  Values  of  0  mean  imaging  all  the
    planes.

2 WCOL

    The  channel from which the weight should be taken.  WCOL set to 0 means
    using the central channel.

2 CONVOLUTION

    Select the desired convolution function for gridding  in  the  UV  plane
    Choices are
            0    Default (currently 5)
            1    Boxcar
            2    Gaussian
            3    Sin(x)/x
            4    Gaussian * Sin(x)/x
            5    Spheroidal
    Spheroidal  functions  is  the optimal choice. So we strongly discourage
    use of any other convolution function.

2 UV_SHIFT

    Logical variable indicating whether map center (i.e. phase tracking cen-
    ter) or orientation should be changed.

2 MAP_RA

    New Right Ascension of map phase center. Used only if UV_SHIFT is YES.

2 MAP_DEC

    New Declination of map phase center. Used only if UV_SHIFT is YES.

2 MAP_ANGLE

    Position  Angle of the direction which will become the apparent North in
    the map. Used only if UV_SHIFT is YES.

1 UV_RESAMPLE
        [CLEAN\]UV_RESAMPLE [Nc Ref Val Inc]

    Resample the UV data loaded by READ UV on a  different  velocity  scale.
    All  other UV commands except UV_COMPRESS work on the "Resampled" UV ta-
    ble.
         Nc   new number of channels
         Ref  New reference pixel
         Val  New velocity at reference pixel
         Inc  Velocity increment
    The "Resampled" UV table is a simple copy of the original  one  after  a
    READ  UV  command, or after a UV_RESAMPLE or UV_COMPRESS command without
    arguments.

1 UV_RESTORE
        [CLEAN\]UV_RESTORE

    Create a Clean image from the UV data set and the Clean Component  list.
    The  Clean  Components  are  subtracted  from the UV data set, and these
    residuals are gridded and Fourier transformed to  compute  the  Residual
    image. This Residual image is added to the Gaussian beam convolved image
    of the sum of Clean components. The results are similar to those of  MX,
    since only the residual are aliased.

    This command can be used after HOGBOM, CLARK, MULTI, SDI or MX (although
    it is pointless after MX), but not MRC which has no notion of Clean Com-
    ponents.

    This command does not work for Mosaic.

1 UV_SORT
        [CLEAN\]UV_SORT TIME|BASE

    Sort and transpose the UV data set, loaded by command READ UV File.  Or-
    der is either TIME for Time-Baseline ordering,  BASE  for  Baseline-Time
    ordering.  The sorted UV data is then available in variable UVS for fur-
    ther plotting. ** Is this done in the internal buffer? **

1 UV_STAT
        [CLEAN\]UV_STAT TAPER|WEIGHT|CELL [Step Start]

    Predict the synthesized beam, expected noise level, and recommended pix-
    el  size  for  different values of tapering distance or robust weighting
    threshold or uv cell size. UV_STAT allows the astronomer to  select  the
    best  weighting  parameters  according to its personal trade off between
    angular resolution and sensitivity.

    For TAPER, beam sizes and noise level (in flux and brightness)  will  be
    computed  for  9 different tapers (from Start to Start*Step^9).  Default
    value for Step is sqrt(2), Default value for Start is  50  m.  Weighting
    mode,  UV  cell  size  and  "robust"  parameter  are taken from variable
    UV_CELL.

    For WEIGHT, beam sizes and noise level (in flux and brightness) will  be
    computed  for  9  different "robust" weighting parameters (from Start to
    Start*Step^9). Default value for Step is sqrt(10), and default value for
    Start  is  derived to center the "robust" parameter values around 1.  UV
    cell size is taken from variable UV_CELL[1], and  Taper  is  taken  from
    variable UV_TAPER.

    For  CELL,  beam  sizes  and noise level are computed for 9 different UV
    cell sizes. This version is still under development.


1 VIEW
        [CLEAN\]VIEW Variable [First [Last]]

    where
        RESIDUAL, CLEAN, NEAT, NMR, SUPPORT or MASK)
        are optional arguments to restrict the range of channels to be plot-
    ted (default FIRST and LAST variables)

    The  buffer is loaded in SIC Header variable W, and then displayed using
    the p_view procedure like in GO VIEW.  See SHOW for an alternative.

1 WIPE
        [CLEAN\]WIPE [INFO | APER | BEAM | SOLVE [/INTERACTIVE] | ERROR]

    WIPE is a deterministic deconvolution method using a limited CLEAN as  a
    starting point. WIPE applies a regularization principle and provides er-
    ror analysis on the deconvolution process.  A  strategy  is  defined  in
    WIPE  to  build  automatically the effective support of the object under
    observation.  However a starting support (analog to a Clean Support) can
    be defined to restrict the search.

    WIPE  INFO  displays information about the UV table relevant to the WIPE
    deconvolution method. WIPE APER fit an ellipse to the observed UV tracks
    to  define  the region where the experimental frequency coverage will be
    interpolated by the WIPE deconvolution method. In other words,  this  is
    the  definition  of  the frequency coverage to be synthesized. WIPE BEAM
    computes the neat and the dirty beams for the WIPE deconvolution method.
    WIPE  SOLVE starts the WIPE deconvolution method. The control parameters
    are
        MAP_SIZE     [pixels] Number of pixels of the mapped image
        MAP_CELL     [arcsec] Size of map cell in arcsec
        WIPE%PROC    [      ] Channel number to process in uv file
        WCOL         [      ] Channel to use for weighting
        WEIGHT_MODE  [      ] Weighting mode (NA|UN)
        WIPE%APER    [      ] Axis of the ellipse to interpolate

    A typical session using wipe is
        read uv file.uvt
        let map_size 256
        let map_cell 0.15
        uv_map
        show beam
        show dirty
        polygon
        let wipe%nclean 100
        let wipe%gain 0.2
        let wipe%cycle 50
        let wipe%proc 0
        wipe info
        wipe aper
        wipe beam
        wipe solve
        show residual
        show neat
        wipe error
        write dirty file
        write beam file
        write neat file

2 MAP_SIZE

    Number of pixels in each direction of the image.

2 MAP_CELL

    Size of pixel in each direction [arcsec].

2 WIPE%PROC

    Channel number to be processed. If 0 is selected, WIPE SOLVE will  auto-
    matically set the default to 1.

2 WCOL

    The column number of the input UV table to be used to get the visibility
    weights.

2 WEIGHT_MODE

    Two weighting modes are available. The 'UN' or uniform weight  mode  at-
    tributes the same contribution to each weight. Whereas the 'NA' or natu-
    ral mode takes into account the local density of visibilities.

2 WIPE%APER

    Multiplicative factors to apply on major and minor axis of  the  default
    ellipse characterizing the aperture to be synthesized in the uv plane.

1 WRITE
        [CLEAN\]WRITE Buffer File [/PLANE First Last] [/TRIM]

    WRITE  the  specified buffer (UV, BEAM, PRIMARY, DIRTY, CLEAN, RESIDUAL,
    SUPPORT, CCT, NEAT, NMR) onto a File. Default extension are  uvt,  beam,
    lmv, lobe, lmv-clean, lmv-res, pol, cct, lmv-neat, lmv-nmr.

    A range of image planes can be specified through /PLANE option.

    For  UV data, the flagged data are written by default. They may be omit-
    ted using the /TRIM option.

1 ENDOFHELP





































