SDI

        CLEAN [FirstPlane [LastPlane]] [/PLOT Clean|Residu]  [/FLUX  Fmin  Fmax]
    [/QUERY] [/RESTART [File]]

    with METHOD = SDI

    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  ex-
    tended  sources and UV coverages with short spacings. In such a case, it may
    avoid the "ringing" features which appear using the CLARK  or  HOGBOM  tech-
    niques. In mosaic mode (see command MOSAIC), a mosaic clean is performed.

    SDI  is  very  sensitive  to the selected support (see MASK and SUPPORT com-
    mands), especially when the dirty beam sidelobes are significant.