[daip] IMAGR. UVWTFN, ROBUST

[Gustaaf van Moorsel]

I am confused about the weighting behavior in IMAGR.
Leaving UVWTFN blank, I get the following beam sizes:

ROBUST     beam
  -4     1.26 x 0.68
   0     1.22 x 1.09
   4     1.92 x 1.43

as expected.

When, however, I leave ROBUST at 0, and set UVWTFN to 'UN',
I get the following beam: 1.22 x 1.09, whereas I would have
expected 1.26 x 0.68.  It is as if the value of UVWTFN is
being ignored.  If I set UVWTFN to 'NA', the beam becomes
1.92 x 1.43, as expected.

Gustaaf