[daip] Position offsets in UVFIT

[Andy Biggs]

Hi there. I'm trying to fit to the u,v visibilities of a source *far* from the phase centre with UVFIT. If I shift the data to the phase centre with UVFIX then the fitting goes fine with GPOS=0. However, if I try fitting to the un-UVFIX'd data, then I can't get sensible answers. I use IMDIST to tell me the x and y offsets of the source relative to the phase centre and use these in UVFIT - should that work?

I want to subtract the source from the data, taking into account its variation with HA due to the primary beam. I do this by model fitting as a function of time and don't want to UVFIX the data twice.

Cheers,

Andy