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NRAO Home > CASA > CASA Task Reference Manual |
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0.1.27 fixvis
Requires:
Synopsis
Recalculates (u, v, w) and/or changes Phase Center
Description
Recalculates (u, v, w) and/or changes Phase Center
Arguments
Inputs |
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vis |
| Name of the input visibility set.
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| allowed: | string |
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| Default: |
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outputvis |
| Name of the output visibility set. (Can be the same as
vis.)
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| allowed: | string |
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| Default: |
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field |
| Fields to operate on. ” = all.
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| allowed: | any |
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| Default: | variant ”” | |
refcode |
| reference frame to convert UVW coordinates to
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| allowed: | string |
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| Default: |
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reuse |
| base UVW calculation on the old values?
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| allowed: | bool |
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| Default: | True |
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phasecenter |
| use this direction as phase center
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| allowed: | string |
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| Default: |
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distances |
| (experimental) List of the distances (as quanta) of the
fields selected by field.
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| allowed: | any |
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| Default: | variant ”” |
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datacolumn |
| when applying a phase center shift, modify visibilities
only in this/these column(s)
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| allowed: | string |
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| Default: | all |
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If the phase center is changed, the corresponding modifications are applied to the
visibility columns given by the parameter "datacolumn" which is by default set
to "all" (DATA, CORRECTED, and MODEL).
Input Parameters
vis -- Name of the input visibility set
outputvis -- Name of the output visibility set, default: same as vis
field -- field selection string
refcode -- Reference frame to convert to, default: the refcode of PHASE_DIR in the
FIELD table
example: ’B1950’
reuse -- base recalculation on existing UVW coordinates? default=True
ignored if parameter ’phasecenter’ is set
phasecenter -- if set to a valid direction: change the phase center for the given
field to this value
example: ’J2000 9h25m00s -05d12m00s’
If given without the equinox, e.g. ’0h01m00s +00d12m00s’, the parameter
is interpreted as a pair of offsets in RA and DEC to the present
phasecenter.
NOTE: The RA offset can be given in units of time or angle. If given
as a time (i.e. as a single number with a time unit as in, e.g., 12s
or in the XXhXXmXXs or XX:XX:XX.XXX formats), it is applied as is.
If given as an angle (e.g., 0.01deg), it is divided by the cos(DEC)
before it is applied.
distances -- (experimental) List of the distances (as quanta) of the fields selected by field
to be used for refocussing.
If empty, the distances of all fields are assumed to be infinity.
If not a list but just a single value is given, this is applied to
all fields.
default: []
examples: [’2E6km’, ’3E6km’] ’15au’
datacolumn -- when applying a phase center shift, modify visibilities only in
this/these column(s)
default: ’all’ (DATA, CORRECTED, and MODEL)
example: ’DATA,CORRECTED’ (will not modify MODEL)
Examples:
fixvis(’NGC3256.ms’,’NGC3256-fixed.ms’)
will recalculate the UVW coordinates for all fields based on the existing
phase center information in the FIELD table.
fixvis(’Moon.ms’,’Moon-fixed.ms’,’Moon’, ’’, ’J2000 9h25m00s 05d12m00s’)
will set the phase center for field ’Moon’ to the given direction and recalculate
the UVW coordinates.
More information about CASA may be found at the
CASA web page
Copyright © 2016 Associated Universities Inc., Washington, D.C.
This code is available under the terms of the GNU General Public Lincense
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