%N zedfudge %F $MIR/src/subs/zed.for
%D Calculate sigma fudge factor, for Zeeman experiments.
%P nebk
%: zeeman
%B
      subroutine ZedFudge(mode,ispect,vspect,m,n1,n2,a,b,fudge,
     *                                                rho,beam,nx,ny)

      character mode*(*)
      integer m,n1,n2,nx,ny
      real ispect(m,n1*n2),vspect(m,n1*n2)
      real a,b,fudge,rho,beam(nx*ny)
  ---------------------------------------------------------------------
  This determines the fudge factor that the sigma_{alpha} estimate
  should be multiplied by to give a correct value. This is used when
  the noise is correlated.

  Inputs:
    mode       '2' indicates that we should use a two sided derivative.
    m          Number of channels.
    n1,n2      Number of pixels in x and y.
    ispect     I spectra.
    vspect     V spectra.
    a,b        Values of alpha and beta to use.
    rho        Correlation factor in the spectral dimension.
    beam       Dirty beam patch.
    nx,ny      Size of the dirty beam patch.

  Output:
    fudge      Sigma fudge factor.  Sigma estimates derived by ignoring
               the noise correlation should be multiplied by this fudge
               factor to get better error estimates.
