msuvbin

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0.1.77 msuvbin

Requires:

Synopsis
grid the visibility data onto a defined uniform grid (in the form of an ms); multiple MS’s can be done onto the same grid

Description

msuvbin is a uv gridding task. The use is for large volumes of data (from multiple epochs) that needs to be imaged into one image. One way of proceeding is to image the epochs and average them after wards. Rather than doing this averaging the visibilities on a common uv grid has several convenience advantages like easily doing the proper weighted averaging and imaging. If an output grid already exists and a second ms is gridded on the grid then the output grid parameters is ignored but the existant grid is used.

Arguments


Inputs
vis	Name of input visibility file (MS)
	allowed:	string
	Default:
field	Field selection of input ms
	allowed:	string
	Default:
spw	Spw selection
	allowed:	string
	Default:
taql	TaQl string for data selection
	allowed:	string
	Default:
outvis	name of output uvgrid
	allowed:	string
	Default:
phasecenter	phase center of uv grid
	allowed:	string
	Default:
nx	Number of pixels of grid along the x-axis
	allowed:	int
	Default:	1000
ny	Number of pixels of grid along the y-axis
	allowed:	int
	Default:	1000
cell	pixel cell size defined in sky dimension
	allowed:	string
	Default:	1arcsec
ncorr	number of correlations to store in grid
	allowed:	int
	Default:	1
nchan	Number of spectral channels in grid
	allowed:	int
	Default:	1
fstart	Frequency of first spectral channel
	allowed:	string
	Default:	1GHz
fstep	spectral channel width
	allowed:	string
	Default:	1kHz
wproject	Do wprojection correction while gridding
	allowed:	bool
	Default:	False
memfrac	Limit how much of memory to use
	allowed:	double
	Default:	0.5

Returns
void

Example

       Keyword arguments:
       vis -- Name of input visibility file
              default: none; example: vis=’ngc5921.ms’
       field -- Field name list
               default: ’’ ==> all
               field = ’1328+307’  specifies source ’1328+307’
               field = ’4’ specified field with index 4
       spw -- Spw selection
               default: spw = ’’ (all spw)
       spw=’2’
       taql  --TaQl expression for data selection (see http://www.astron.nl/casacore/trunk/casacore/doc/notes/199.html)
               default taql=’’
       Example select all data where U > 1 m in the ms
       taql=’UVW[0] > 1’
       outvis -- name of output grid
               default: ’’  The user has to give something here
       phasecenter -- phasecenter of the grid
               default= ’’
                phasecenter=’J2000 18h03m04 -20d00m45.1’
      nx  -- number of pixels along the x axis of the grid
               default: 1000
       nx=1200
      ny  -- number of pixels along the y axis of the grid
               default: 1000
       ny=1200
       cell -- cellsize of the grid (given in sky units)
               default: ’1arcsec’
               cell=’0.1arcsec’
ncorr -- number of correlation/polarization plane in uv grid (allowed 1, 2, 4)
               default: 1
               ncorr=4
        nchan -- number of spectral channel
       default: 1
               nchan=2000
        fstart -- frequency of the first channel
               default: ’1GHz’;  User has to give something useful here
        fstep -- spectral channel width
               default: ’1kHz’
        wproject -- do wprojection correction while gridding
                default: False
                wproject=True
        memfrac -- control how much of computer’s memory is available for  gridding
                default=0.5
                memfrac=0.9

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