[daip] task DBCON

[Hermine Landt]

 hi Amy,

thank you for your help.
I have another question concerning imaging the combined data set. I choose
the values for BJMIN and BJMAX which give the most appropriate results,
however, I don't properly understand the significance of PA (the position
angle). Should I set it to zero? Is there a recommended value.

   thanks.   Hermine



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   Hermine Landt
   Harvard-Smithsonian           E-mail: hlandt at cfa.harvard.edu
     Center for Astrophysics     Phone:  +1-617-496-7824
   60 Garden Street, MS-70       Fax:    +1-617-495-7356
   Cambridge, MA 02138, USA

                http://hea-www.harvard.edu/~hlandt/
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On Wed, 21 Sep 2005, Amy Mioduszewski wrote:

> Hi Hermine,
>
>  From my experience combining different VLA configurations, it is better
> to self-cal first, then DBCON.  You'll have to do some self-calibration
> after you combine them, but it is easier to get them to converge if the
> data going in is well calibrated to begin with.
>
> I've had to do lots of experimenting though.  Do you have many different
> arrays?  I've also found that adding arrays one at a time is the best
> way to proceed.  I know it is more work, but glombing everything
> together and expecting it just to work out doesn't seem to work very
> well.  I usually go from smaller configurations to larger as well, i.e.,
> self-cal everything, combine D and C, do some self-cal, add B, do some
> self-cal, add A...
>
> Also, experiment with UVBOX in IMAGR, this seems to work better
> adjusting the weighting than just adjusting ROBUST.
>
> Again, there is no perfect recipe, I'm just telling you what seems to
> work best for me.  You will probably have to experiment yourself.
>
> Cheers,
>
> Amy
>