MAKE_MOSAIC

    This task combines individual dirty images and  beams  corresponding  to
    various  pointing  centers  into  a "mosaic" which is suited for further
    deconvolution using the MAPPING program.

    Mosaics are ensemble of overlapping fields, with  typically  half  power
    primary  beam  overlap, and similar (but not identical) UV coverages for
    each field. Individual images for every field should be created with   a
    common   phase  tracking  center.  The  UV_SHIFT,  MAP_RA  and   MAP_DEC
    variables in task UV_MAP must be used for this.  The  image  names  must
    derive from a generic name as follows (e.g. for a generic name  MAP)
         MAP-1.LMV, MAP-2.LMV, ... MAP-N.LMV
    where N is the number of fields.

    For example
    LET MAPSIZE 256 512
    LET MAPCELL 0.5
    LET UVSHIFT YES
    LET MAPRA     20:39:10
    LET MAPDEC    68:01:20
    !
    LET WCOL 1
    FOR I 1 TO 10
    LET NAME CONT-'I'
    GO UVMAP
    NEXT

    MAKE_MOSAIC produces a combined image (MAP.LMV), a data cube of  primary
    beams  (MAP.LOBE),  a  data cube of dirty beams (MAP.BEAM), and a weight
    image MAP.WEIGHT, which are required for cleaning.

    Two parameters are very important in the mosaic  creation:  the  primary
    beam  width (FWHM), and the truncation threshold of the primary beam. It
    is recommended to use a relatively high value for this threshold, 0.2 to
    0.4, to avoid contaminating adjacent field in case of pointing errors.