[daip] UVMOD/UVFIX question

[Eric Greisen]

Hanno Spreeuw wrote:
> Thank you,
> 
> It seems that inserted sources with FPOS<>0 do not appear in the images 
> exactly where they should. The errors increase away from the tangent 
> point. This confirms earlier results by James Miller-Jones (CC). 
> However, with FPOS=0, the source always appears at the tangent point.
> We are testing new source extraction code. In order to check our 
> deblending algorithm, we are inserting many sources in a small patch of 
> the sky. With these artificial sources one always knows the true flux 
> and position, so that is good for testing.
> I am considering the workaround with UVFIX for these tests.

If what you say is true, then it is unlikely for any of AIPS to work 
correctly.  UVMOD uses the same phasing routines used elsewhere in AIPS 
including but not limited to UVFIX and IMAGR.  What telescope has 
produced your data and what are you doing?

Eric Greisen