FIT FixedValues
Clean beam parameters can also be specified by the users, by loading the
BEAM_SIZE array with values other than its default values (0,0,0). In this
case, no automatic fit will be performed.
In general, we discourage this usage, as it may result in a very improper
flux scaling if the beam size is inappropriate. This mode should be reserved
to special cases where the beam cannot be properly fitted, or to have a cir-
cular beam by taking as beam size the geometrical mean of the fitted major
and minor sizes.
Fixing the beam size should be associated to the FIT /JVM command to mini-
mize (but not suppress !...) errors in total flux scaling.