[daip] clean component filtering

[Andy Biggs]

Hi there. I'm having a difficult time at the moment with some map 
making. I have a lot of maps to make and I want to do it in as 
*automated* a fashion as possible. I am doing a wide-field deep clean at 
21cm and am using a fly's-eye faceting approach. The problem is that 
some of the facets do not contain any sources which results in them 
ending up with lots of weak, spurious clean components which I want to 
exclude from CALIB (this is before each epoch is combined together with 
STUFFR).

My favoured way of dealing with this would be to run CCEDT. However, it 
seems that in those fields where all the clean components would be 
(correctly) rejected, CCEDT doesn't do what I would like it to, and 
which I think it should, which is to write out a new *empty* CC table.

I've tried various other approaches, such as flagging the entries using 
TAFLG, but that caused CALIB to do some very strange things, mainly only 
using a small and somewhat random number of the many fields. I've tried 
running IMAGR with the filtering option (IMAGRPRM(8,9)) but this didn't 
seem to do anything at all i.e. IMAGR didn't even begin (nothing 
appeared in the MSGSRV and no activity was reported by 'top'). One thing 
that sort of worked was to set field cards as 'F -1 -1 0 0' in BOXFILE 
which prevented IMAGR placing a box in that field. However, you then 
need to tell IMAGR the size of the field through IMSIZE and you can only 
do this once i.e. if you have different sized fields (which I do) you 
can't really do this. Also, you need to know in advance which fields 
aren't going to have any sources.

Anyway, I was wondering if you agree that CCEDT should write out an 
empty CC table if no components are selected? I think that that would 
help me a lot.

Thanks,

Andy

p.s. I'm running a very recently midnight-jobbed version of 31DEC08 on a 
MacBook Pro.

-- 

Andy Biggs
ESO, ALMA Regional Centre
Karl-Schwarzschild-Strasse 2
D-85748 Garching, Germany

tel. +49-89-32006471
fax. +49-89-32006898