[daip] AIPS Multi-resolution cleaning

[Eric Greisen]

Carlos Alanias Rodriguez Rico writes:

 > I have been playing around with multi-resolution cleaning and the 
 > IMAGPRM(11) and IMAGPRM(12) are not at all clear to me as how to determine 
 > these input values. I read the explain file for IMAGR already.
 > The special problem is IMAGPRM(11) which as explained is something related 
 > to the weighting scheme used to select which resolution is prefered.
 > The peak flux density in each of the selected resolutions is weighted by 
 > 1/R**IMAGPRM(11). Could you give me an example on how todetermine this 
 > value ( 0.2, 0.8 or 1)? and what is the criteria used to choose this 
 > value?
 > 

The idea is to make all resolutions about equal.  I usually start by
doing the imaging with some guess for the parameters - but I write
down the peak brightness in each resolution and the beam sizes before
any Cleaning is done.  Then I estimate IMAGRPRM(11) to make the
weighted maxima about the same.  If the source consists of point
sources, all the maxima will be about the same in Jy/beam and the
parameter should be 0.  If the source is very extended, then tha
maxima about equal the beam area and the parameter should be 1.0.
Your source will be in between these extremes.

Eric Greisen