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A worked example: VLA 4m imaging of Coma

Here is an example of a Glish script which was used to image the Coma cluster at 74MHz with data from the VLA in the B and C configurations.

include 'dragon.g'
myms := fitstoms('coma.ms','COMA-4CB-CUT.FITS',T,F)     # Convert from FITS to MS
myms.done()
#
drgn := dragon('coma.ms')                               # Create Dragon tool
drgn.setimage(name='coma',nx=1800, ny=1800,             # Set imaging parameters
              cellx='30arcsec', celly='30arcsec', 
              doshift=F, 
              phasecenter=dm.direction('J2000','0deg','0deg'), 
              mode='mfs', facets=25)
#
drgn.setoutlier(name='CenA' , nx=400, ny=400,           # CenA outlier field
                cellx='37arcsec', celly='37arcsec' , 
                doshift=T,  mode='mfs',
                phasecenter=dm.direction('J2000','201.3deg','-42.6deg'),
                nchan=1, start=1, step=1, spwid=1, fieldid=1)
#
#setting an outlier field towards Virgo-A; note for direction we have
# made use  of the inbuilt radio catalog 
drgn.setoutlier(name='VirA' , nx=400, ny=400,           # VirgoA outlier from builtin catalog
                cellx='37arcsec', celly='37arcsec' , 
                doshift=T, mode='mfs',
                phasecenter=dm.source('VIRGOA'), 
                nchan=1, start=1, step=1, spwid=1, fieldid=1)
#
drgn.uvrange(uvmin=0, uvmax=10000000)                   # uv range
drgn.weight(type="uniform")                             # uniform weighting
drgn.setoptions(padding=1.5, cache=0)                   # padding for the Fourier Transform
#
drgn.image(levels='1Jy 0.3Jy 0.1Jy',                    # image and selfcalibrate
           amplitudelevel='0.2Jy',   
           timescales='200s 200s 100s', 
           niter=50000, gain=0.05, 
           threshold='0.05Jy', plot=F, display=F)
#
drgn.done()

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