Once you have settled on the resolution 
, baseline range
and observing frequency 
for your program, the next decision (see
the continuum decision tree again)
involves IF bandwidth 
and averaging time 
. These
must be consistent with the field of view requirements of your
program. You must therefore consider the radius 
(from the
center of the field of view) over which you require the data to be
minimally distorted by chromatic aberration and time-average smearing
as discussed in Lectures 3 and 10 (and in Bridle & Schwab
1989).