UV_SHORT Zero_Spacing

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UV_SHORT Zero_Spacing

              Zero  spacings  are  computed when the single dish diameter is the
        same as the interferometer dish diameter. Zero spacing  extraction  pro-
        ceeds differently for Class data tables and 3-D data cubes.

        In  the data cube case, the nearest pixel matching the direction of each
        field is taken as the Zero spacing for this field. If there is no  point
        close  enough, according to the specified position tolerance SHORT_TOLE,
        an error occurs.

        In the Class data table case, all spectra within the specified  position
        tolerance  of  a  field center are averaged together to produce the Zero
        spacing. If none is found, an error occcurs.