Documentation on pcsub

Task: pcsub
Purpose: Subtract a plane (optional by polynomial fit) from a cube
Categories: map combination

   PCSUB (Polynomial Continuum Subtraction) is a MIRIAD task which
   submits selected planes of a cube to a polynomial least squares
   fit to make a continuum map that can be subtracted from the input 
   cube. Optionally, if a continuum map is already known, this can
   be subtracted also.

Key: in
   The input image dataset. No default.

Key: out
   The output image. For default see cont= keyword.

Key: order
   The order of the highest term of the polynomial fit. 
   Default is 0, i.e. a constant.

Key: region
   Specify the channels to fit with a command of the region
   of interest format, e.g. 
        region=image(1,5),image(120,128)
   This would fit and subtract channels 1:5 and 120:128 from the
   cube.  Note that blanked planes are correctly ignored, but
   isolated blanked pixels in a plane are not.

Key: cont
   If ``out'' is provided, the continuum is generated from the
   region (channels) selected.  This continuum (cont=) is subtracted from
   each of the channels of the cube (in=) to yield an output cube (out=)
   If ``out'' alone is provided, this is all that occurs.  
   If ``cont'' is also provided, the continuum map is also written to 
   the file specified, if that file did not exist yet.
   If ``cont'' did already exist, it is assumed to be the continuum map,
   and subtracted from the input cube. 
   If ``cont'' alone is provided, ONLY the continuum map is written, no
   output cube is written.