No visibility at spacings shorter than SHORT_UV_MIN is generated. If
the "short spacing" data comes from a single-dish, this value could be
set to Zero.
However, if, for example, one uses an ACA image as short spacings for an
ALMA data set, the shortest baseline is the ACA antenna diameter, 7 m.
SHORT_UV_MIN should then be set to 7 in this case (unless the ACA image
includes the total power data in it already).
Default value is 0.