[daip] New Staff Reply - [!WEG-138951]: combining D and C array data in the UV plane

[Eric Greisen]

New Staff Reply: combining D and C array data in the UV plane

DBCON will only allow you to combine data sets with the same number of
channels and roughly the same frequency and frequency increment.  Tasks
CVEL and SPECR may be able to help get them close but then UVCOP with
BCHAN and ECHAN will be necessary to throw away channels to match the C 
array data.

I do not understand - if M87 is in the primary beam at D array it must
also be in the primary beam at C array.  If it is not in either primary
beam, then it is not possible to use ordinary continuum fitting tasks
(UVLSF) to remove it since the assumption that the visibility is a
straight line in real and imaginary (after shifting to phase center)
is unlikely to be correct.  Removing a good image of M87 from data in
an outer sidelobe also will not work since the "source" you observed
in that sidelobe is a corrupted version of the real source.

I suspect that you will have to do imaging with the continuum still in
the data - which will be very much more expensive and then try to fit and
remove the continuum afterwards in the image plane.

Eric Greisen


Ticket Details
===================
Ticket ID: WEG-138951
Department: AIPS Data Processing
Priority: Default
Status: Closed
Link:  https://help.nrao.edu/staff/index.php?_m=tickets&_a=viewticket&ticketid=785