# CASA Basic Calibration demo
# gmoellen (07Oct15)


# fill from UVFITS
default(importuvfits);
importuvfits(fitsfile='NGC5921.fits',
             vis='ngc5921.ms');

# flag autocorrs
flagautocorr(vis='ngc5921.ms');

# list dataset info
listobs(vis='ngc5921.ms');


# a quick look at the data
default(plotxy);
plotxy(vis='ngc5921.ms',
       xaxis='time',
       yaxis='amp',
       datacolumn='model');
plotxy(xaxis='uvdist',
       datacolumn='data',
       field='1331*');
plotxy(field='1445*');


# set the 1331+305 (3C286) model
default(setjy);
setjy(vis='ngc5921.ms',
      field='1331*');

default(plotxy);
plotxy(vis='ngc5921.ms',
       xaxis='uvdist',
       yaxis='amp',
       datacolumn='model',
       field='1331*, 1445*');


# a preliminary G on the bandpass calibrator (using central 1/3 channels)
#  to remove any time-dependence
default(plotcal);
default(gaincal);
gaincal(vis='ngc5921.ms',
        caltable='prelim.G',
        field='1331*',
        spw='0:20~40',
        solint=20.0);
plotcal(yaxis='phase');
plotcal(yaxis='amp');

# Bandpass using preliminary G
default(plotcal);
default(bandpass);
bandpass(vis='ngc5921.ms',
         caltable='cal.B',
         field='1331*',
         solint=0.0,
         gaintable='prelim.G');
plotcal(yaxis='amp');
plotcal(yaxis='phase');

# a final G on both calibrators, using B 
default(plotcal);
default(gaincal);
gaincal(vis='ngc5921.ms',
        caltable='final.G',
        field='1331*, 1445*',
        spw='',solint=0.0,
        gaintable='cal.B');
plotcal(yaxis='amp');
plotcal(yaxis='phase');

# transfer flux density from 1331+305 to 1445+099
default(fluxscale);
fluxscale(vis='ngc5921.ms',
          caltable='final.G',
          fluxtable='final.Gflx',
          reference='1331*');
plotcal(caltable='final.Gflx',yaxis='amp');


# apply calibration to calibrators and target
default(applycal);
applycal(vis='ngc5921.ms',
         field='1331*',
         gaintable=['final.Gflx','cal.B'],
         gainfield=['1331*','']);
applycal(field='1445*, N5921*',
         gainfield=['1445*','']);


# examine calibrated calibrators 
default(plotxy);
plotxy(vis='ngc5921.ms',
       xaxis='uvdist',
       yaxis='amp',
       datacolumn='corrected',
       field='1331*',
       spw='0:3~60');
plotxy(field='1445*');