
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 con‐
vergence, while lower values give a better restitution of the ex‐
tended structure. A sensible default is 0.2.

2 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

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 usually 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 parameter 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 inter‐
section 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
cleaning box.  The actual cleaning window will be  the  intersec‐
tion  of  the  specified window with the inner quarter of the map
and with any user defined polygon.

2 POSITIVE

The minimum number of positive components  before  negative  ones
are selected.

2 KEEP

This is a logical flag to keep cleaning after an approximate con‐
vergence 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. anti‐
clockwise) 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 discourage 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.











































