Jupiter: continuum polarization calibration 5.5.0

Calibration

Set the Flux Scale

Set the absolute flux density scale, but only for Stokes I at the moment. Our primary (flux) calibrator here is 1331+305 (3C286). The default model for CASA 5.3+ is 'Perley-Butler 2017'.

 
setjy(vis='jupiter6cm.demo.ms', field='1331+305')

Initial gain calibration

At this stage the data have an overall flux density scaling determined, but full gain solutions aren't there yet. The relevant task is gaincal (analogous to the AIPS task CALIB). Rather than generate solution tables (SN tables in AIPS) that are attached to the measurement set (UVFITS in AIPS era), gaincal will produce a separate tables, and we will use appropriate extensions to keep track of what is what.

Firstly generate an antenna zenith-angle dependent VLA gain curve calibration table

 
gencal(vis='jupiter6cm.demo.ms', caltable='jupiter6cm.demo.gc', caltype='gc')

Now, solve for antenna gains on 1331+305 and 0137+331, using the just generated gain curve table (.gc).

 
gaincal(vis='jupiter6cm.demo.ms', caltable='jupiter6cm.demo.G', field='1331+305,0137+331', spw='', gaintype='G', calmode='ap', solint='inf', combine='', refant='11', minsnr=3, gaintable=['jupiter6cm.demo.gc'], parang=False)

# Check the solutions
plotcal(caltable='jupiter6cm.demo.G', xaxis='time', yaxis='amp', subplot='333', iteration='antenna')

If all looks good, bootstrap the flux density scale of the flux calibrator onto the phase calibrators. AIPS called it GETJY, but CASA calls it fluxscale.

 
myFluxscale = fluxscale(vis='jupiter6cm.demo.ms', caltable='jupiter6cm.demo.G', fluxtable='jupiter6cm.demo.Gflx', reference='1331+305', transfer='0137+331', append=False, display=False)

Template:Checked 5.3.0

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