1 MX
        MX : Make and Clean maps from UV data

    This task combines UV_MAP  and  CLEAN  in  a  single  step.   The  CLEAN
    algorithm  is  similar  to  the  CLARK  method,  but  with  major cycles
    operating directly on the ungridded UV table rather than  in  the  image
    plane.  Accordingly, there is aliasing only of the residuals, not of the
    clean components.

    MX can process all planes of a data  cube  at  the  same  time,  but   a
    separate  list  of  component  will  be  produced  for  each plane.  The
    cleaning cannot be restarted.

    The mapping process is identical to UV_MAP.  It makes a map from UV data
    by  gridding  the  UV  data  using  a convolving function, and then Fast
    Fourier  Transforming  the  individual  channels.   However,  MX  always
    produces  a  single  beam  for  all  channels, thus neglecting frequency
    change between channels.

    MX allows 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.

    MX produces several output maps, of name derived from MAP_NAME$,  and  a
    residual output UV table.

2 UV_TABLE$
        TASK\FILE "UV table" UV_TABLE$

    The UV table name.  Default extension is .UVT.  This UV  table  will  be
    shifted, rotated and sorted if necessary.
2 MAP_NAME$
        TASK\CHARACTER "Map name" MAP_NAME$

    The output map(s) name, without extension. All output  image  names  are
    derived from this name as follow
        MAP_NAME.LMV-MX    The MX-cleaned map
        MAP_NAME.CCT       The clean component table
        MAP_NAME.LMV-RES   The MX residual map
        MAP_NAME.BEAM      The dirty beam
        MAP_NAME.UVT-MX    The MX residual UV data set
2 UV_TAPER$
        TASK\REAL "UV taper(1/e level, meters)" UV_TAPER$[2]

    The UV taper (to be applied in both directions).
2 WEIGHT_MODE$
        TASK\CHARACTER "Weight mode (NA or UN)" WEIGHT_MODE$

    NAtural (optimum in terms of  sensitivity)  or  UNiform  (usually  lower
    sidelobes)  weighting.  Caution:  UNiform weighting is really disastrous
    for the type of UV coverage obtained at Plateau de Bure.
2 MAP_SIZE$
        TASK\INTEGER "Map size(2)" MAP_SIZE$[2]

    Number of pixels in X and Y.  Need not be a  power  of  two,  but   this
    would be much better for any further image processing.
2 MAP_CELL$
        TASK\REAL "Map cell(arc sec)" MAP_CELL$[2]

    The map cell size. It is recommended to use identical values in X and Y.
2 UV_CELL$
        TASK\REAL "UV cell(m), for unif.  weighting" UV_CELL$[2]

    The UV cell size for uniform weighting.  Should be of the order  of half
    the dish diameter, or smaller.
2 ONEBEAM$
        TASK\LOGICAL "Make one beam (YES), or one per channel (NO)" ONEBEAM$

    For spectral  line  data,  specify  whether  a  common  beam  should  be
    generated for all channels, or one beam per channel.
2 WCOL$
        TASK\INTEGER "Weight channel" WCOL$

    The channel from which the weight should be  taken.   WCOL$  set  to   0
    implies no weighting, and is normally disastrous.
2 MCOL$
        TASK\INTEGER "First and Last channel to map" MCOL$[2]

    The first and last channel to be mapped.

2 CONVOLUTION$
        TASK\INTEGER "Convolution function [0-5]" 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
2 UV_SHIFT$
        TASK\LOGICAL "Change map center or map orientation" UV_SHIFT$

    Indicate whether map center (i.e. phase tracking center) or  orientation
    should be modified or not.

2 RA_CENTER$
        TASK\CHARACTER "Map Center RA" RA_CENTER$

    New Right Ascension of map center.
2 DEC_CENTER$
        TASK\CHARACTER "Map Center DEC" DEC_CENTER$

    New Declination of map center.
2 ANGLE$
        TASK\CHARACTER "Map Position Angle (deg)" ANGLE$

    Position Angle of the direction which will become the apparent North  in
    the map.

2 GAIN$
        TASK\REAL "Loop gain" 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.
2 NITER$
        TASK\INTEGER "Maximum number of clean components" NITER$

    This is the maximum number of components  the  program  will  accept  to
    subtract.   Once it has been reached, the program starts the restoration
    phase.
2 FRES$
        TASK\REAL "Maximum value of residual (Fraction of peak)" 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$.   Once  this  level  has  been
    reached the program stops subtracting, and starts the restoration phase.
    This parameter is normalised to 1 (neither in % nor in db).   It  should
    usually  be  of  the  order  of magnitude of the inverse of the expected
    dynamic range.
2 ARES$
        TASK\REAL "Maximum value of residual (Absolute)" 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$.  Once this level has been reached
    the   program  stops  subtracting,  and starts  the  restoration  phase.
    The unit for this parameter is  the  map  unit.   The  parameter  should
    usually be of the order of magnitude of  the expected noise in the clean
    map.
2 BLC$
        TASK\INTEGER "Bottom left corner of cleaning box" BLC$[4]

    These are the (pixel) coordinates of  the  Bottom  Left  Corner  of  the
    cleaning  box.   Only  the first two coordinates are actually used.  The
    actual cleaning window will be the intersection of the specified  window
    with the inner quarter of the map.
2 TRC$
        TASK\INTEGER "Top right corner of cleaning box" TRC$[4]

    These are the (pixel)  coordinates  of  the  Top  Right  Corner  of  the
    cleaning  box.   Only  the first two coordinates are actually used.  The
    actual cleaning window will be the intersection of the specified  window
    with the inner quarter of the map.
2 POSITIVE$
        TASK\INTEGER "Minimum number of positive components" POSITIVE$

    The minimum number of  positive  components  before  negative  ones  are
    selected.
2 KEEP$
        TASK\LOGICAL "Keep cleaning after convergence" 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$
        TASK\REAL "Clean beam major axis" 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.

2 MINOR$
        TASK\REAL "Clean beam minor axis" MINOR$

    This is the minor axis  (FWHP)  in  user  coordinates  of  the  gaussian
    restoring beam.
2 PA$
        TASK\REAL "Position angle of clean beam" PA$

    This  is  the  position   angle   (from   North   towards   East,   i.e.
    anticlockwise)  of  the  major  axis  of the gaussian restoring beam (in
    degrees).
2 BEAM_PATCH$
        TASK\INTEGER "Size of cleaning beam in pixels" BEAMPATCH$[2]

    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 END