Recalculation of uvw values (fixvis)

NRAO Home > CASA > CASA Cookbook and User Reference Manual

4.7.2 Recalculation of uvw values (fixvis)

Sometimes the u,v,w coordinates of a measurement set are not recorded correctly by the correlator. In those cases, it may be necessary to recalculate them based on the antenna positions. fixvis will perform this task.

#  fixvis :: Recalculates (u, v, w) and/or changes Phase Center
vis                 =         ’’        #  Name of the input visibility set.
outputvis           =         ’’        #  Name of the output visibility set.  (Can be the same
                                        #   as vis.)
field               =         ’’        #  Fields to operate on.   = all.
refcode             =         ’’        #  reference frame to convert UVW coordinates to
reuse               =       True        #  base UVW calculation on the old values?
phasecenter         =         ’’        #  use this direction as phase center
async               =      False        #  If true the taskname must be started using fixvis(...)

A useful feature of fixvis is that it can also change the pahse center of a measrement set. This can be done with absolute corrdinates or using offsets. An example is:

fixvis(vis=’Moon.ms’,outpuvis=’Moon-fixed.ms’,field=’Moon’, phasedir=’J2000 9h25m00s 05d12m00s’)

that will recalculate the u,v,w coordinates relative to the new phase center for the field ’Moon’.

[next] [prev] [prev-tail] [front] [up]

More information about CASA may be found at the CASA web page

This code is available under the terms of the GNU General Public Lincense