[daip] Combining 2 UV data sets with same correlator and antenna settings but pointing in 2 different directions

[Wasim Raja]

Dear Eric

  I would like to know if DBCON is the right task to combine 2
  uv-datasets observed with exactly the same settings (same
  Centre-freq, same BW, same nchan, same antenna config)
  but pointing towards 2 different sources.

  My goal is to use one of the sources to calibrate the other;
  unfortunately the data for the 2 sources are in 2 different FITS
  files. I would also like to add that the 2 sources were observed
  with their observation times interleaved, ie., every alternate
  scan corresponds to the same source (the successive scans
  were put in different FITS-files).

  I used DBCON to combine the 2 single source files (after having
  converted them to MULTI-source format using task MULTI) with
  options:
  DOARR = +1
  DOPOS = -1

  DBCON "appears to have ended successfully" creating the output
  multi source file. The SU table also seem to get the correct source
  names, except that their fluxes are all 0.

  But when I now use UVPLT to plot *one* of these sources I get the
  following error:
localh> UVPLT1: Task UVPLT  (release of 31DEC10) begins
localh> UVPLT1: SOUFIL: ALL SOURCES REJECTED BY SELECTION CRITERIA
localh> UVPLT1: Purports to die of UNNATURAL causes
localh> UVPLT1: localhost    31DEC10 TST: Cpu=       0.0  Real=       0

  However, when I select ALL sources, UVPLT does make the plots
  successfully -- the 2 sources can also be clearly distinguished by
  their fluxes.


  Could you help please? What is the right task for combining uv data
  on 2 different sources observed with the same correlator settings and
  the same antenna configuration?

  regards
  --wasim



-- 
Research Fellow (A&A)
Raman Research Institute
Bangalore--560080
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