[alma-config] Fw: Set of imaging and UV results for C arrays on SIL images

[Bryan Butler]

all,

i don't know if somebody else has already replied to this, but
i'm just catching up on emails since i got back from the IAU...



john wrote:

> 1) Looking at the slices through the long -track synthesised beams there
> are large negatives, I think this can only mean that you havn't used
> true natural  weighting and is what we agreed to simulate in Tuscon, 
> such natural weighting gives the maximum 
> sensitivity and  uses UVWFT  = 'NA' and ROBUST=5; note that I think 
> both UVWGT and  ROBUST need to be set to get true natural weighting. 

i'm pretty sure that if you use UVWTFN='NA', then the ROBUST adverb
is ignored...  if you use UVWTFN='  ' (actually, it doesn't have to
be a blank string - it can be anything that doesn't have an 'N' as
the first character...), and ROBUST > 7, then this is also equivalent
to "natural" weighting...  in practice, any value of ROBUST > about 4
will give you very close to natural weighting.  but, i agree, strict
natural weighting should be used, and to be sure, just use UVWTFN='NA'...

	-bryan