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| − | ==Help on gencal task:==
| + | {{gencal}} |
| − | <pre>
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| − | Specify Calibration Values of Various Types
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| − | | |
| − | The gencal task provides a means of specifying antenna-based
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| − | calibration values manually. The values are put in designated
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| − | tables and applied to the data using applycal.
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| − | | |
| − | Current antenna-based gencal options (caltype) are:
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| − | 'amp'= amplitude correction
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| − | 'ph' = phase correction
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| − | 'sbd'= single-band delay (phase-frequency slope for each spw)
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| − | 'mbd'= multi-band delay (phase-frequency slope over all spw)
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| − | 'antpos' = ITRF antenna position corrections
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| − | 'antposvla' = VLA-centric antenna position corrections
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| − | | |
| − | The calibration specifications are not time-variable in the
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| − | present implementation. Calibration values can be assigned to
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| − | each spw, antenna and pol selection, where applicable. The
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| − | same caltable can be specified for multipl runs of gencal,
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| − | in which case the specified parameters will be incorporated
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| − | cumulatively. E.g., amplitude parameters (caltype='amp')
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| − | multiply and phase-like parameters ('ph', 'sbd','mbd','antpos')
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| − | add. 'amp' and 'ph' parameters can be incorporated into the
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| − | same caltable (in separate runs), but each of the other types
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| − | require their own unique caltable. A mechanism for
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| − | specifying manual corrections via a text file will be provided in
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| − | the future.
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| − | | |
| − | The caltables are applied to the data by using applycal. Other
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| − | calibration tables must also be present, if applicable.
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| − | | |
| − | For antenna position corrections (caltype='antpos'), the antenna
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| − | position offsets are specified in the ITRF frame. For VLA position
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| − | corrections in the VLA-centric frame, use caltype='antposvla', and gencal
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| − | will rotate them to ITRF before storing them in the output caltable.
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| − | | |
| − | Keyword arguments:
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| − | | |
| − | vis -- Name of input visibility file
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| − | default: none. example: vis='ngc5921.ms'
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| − | caltable -- Name of input/output caltable. If it does not
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| − | exist, it will be created. Specifying an
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| − | existing table will result in the parameters
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| − | being applied cumulatively. Only a single
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| − | time-stamp for all calibrations are supported,
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| − | currently. Do not use a caltable
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| − | created by gaincal, bandpass, etc.
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| − | default: none. example: caltable='test.G'
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| − | caltype -- The calibration parameter type being specified.
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| − | Options include:
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| − | 'amp' = gain (G) amplitude (1 real parameter per
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| − | pol, antenna, spw)
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| − | 'ph' = gain (G) phase (deg) (1 real parameter per
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| − | pol, antenna, spw)
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| − | 'sbd' = single-band delays (nsec) (1 real parameter
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| − | per pol, antenna, spw)
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| − | 'mbd' = multi-band delay (nsec) (1 real parameter
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| − | per pol, antenna, spw)
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| − | 'antpos' = antenna position corrections (m) (3 real
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| − | ITRF offset parameters per antenna; spw, pol
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| − | selection will be ignored)
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| − | 'antposvla' = antenna position corrections (m) specified
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| − | in the old VLA-centric coordinate system
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| − | default: none.
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| − | example: caltype='ph'
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| − | spw -- Spectral window selection for specified parameters.
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| − | default: spw='' (specified parameters apply to all spws)
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| − | example: spw = '2,3,4'
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| − | antenna -- Antenna selection for specified parameters.
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| − | default: antenna='' (specified parameters apply to all antennas)
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| − | example: antenna='EA02, EA03' (specified parameter(s) to
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| − | apply to EA02 and EA03 only)
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| − | pol -- Polarization selection for specified parameters.
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| − | default: pol='' (specified parameters apply to all polarizations)
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| − | example: pol='R' (specified parameters to apply to
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| − | R only)
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| − | parameter -- The calibration parameters, specified as a list, to
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| − | store in the caltable for the spw, antenna, and pol
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| − | selection. The required length of the list is
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| − | determined by the caltype and the spw, antenna, pol
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| − | selection. One "set" of parameters (e.g., one value
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| − | for 'amp', 'ph', etc., three values for 'antpos')
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| − | specified the same value for all indicated spw, antenna,
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| − | and pol.
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| − | OR,
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| − | When specifying a long list of calibration parameter values,
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| − | these should be ordered first (fastest) by pol (if pol!=''),
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| − | then by antenna (if antenna!=''), and finally (sloweset) by
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| − | spw (if spw!=''). Unspecified selection axes must not be
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| − | enumerated in the parameter list
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| − |
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| − | Examples:
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| − | | |
| − | gencal(vis='test.ms',caltable='test.G',caltype='amp',
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| − | spw='',antenna='',pol='',
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| − | parameter=[3])
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| − | | |
| − | --> Antenna-based gain amplitude corrections for all spws, antennas,
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| − | and polarizations will be multiplied by 3. When applied
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| − | to visibility data, this correction will produce a
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| − | corrected visibility than is (1/3*1/3) less than the
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| − | uncorrected visibility.
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| − | | |
| − | gencal(vis='test.ms',caltable='test.G',caltype='ph',
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| − | spw='',antenna='EA03,EA04',pol='',
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| − | parameter=[45,120])
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| − | | |
| − | --> Gain phase corrections for antennas EA03 and EA04
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| − | will be adjusted (additive) by 45 and 120
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| − | degrees (respectively), for all spws and polarizations.
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| − | When these phases are applied to visibility data, the
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| − | visibility phases will decrease or increase by the
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| − | specified amount where the selected antennas occur
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| − | first or second (respectively) in each baseline. E.g.,
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| − | the phase of baseline EA03-EA04 will change by (-45+120)
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| − | = + 75 degrees. Baseline EA01-EA03's phase will change
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| − | by +45 degrees; baseline EA04-EA05's phase will change
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| − | by -120 degrees. The same phase sign convention is
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| − | used for delay and antenna position corrections.
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| − | | |
| − | gencal(vis='test.ms',caltable='test.G',caltype='ph',
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| − | spw='',antenna='EA05,EA06',pol='R',
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| − | parameter=[63,-34])
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| − | | |
| − | --> Gain phase corrections for antennas EA05 and EA06
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| − | will be adjusted (additive) by 63 and -34
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| − | degrees (respectively), in R only, for all spws
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| − | | |
| − | gencal(vis='test.ms',caltable='test.G',caltype='ph',
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| − | spw='',antenna='EA09,EA10',pol='R,L',
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| − | parameter=[14,-23,-130,145])
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| − | | |
| − | --> Gain phase corrections in all spws will be adjusted for
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| − | antenna EA09 by 14 deg in R and -23 deg in L, and for
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| − | antenna EA10 by -130 deg in R and 145 deg in L.
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| − | | |
| − | gencal(vis='test.ms',caltable='test.G',caltype='ph',
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| − | spw='2,3',antenna='EA09,EA10',pol='',
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| − | parameter=[14,-23,-130,145])
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| − | | |
| − | --> Gain phases corrections in both polarizations will be adjusted for
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| − | antenna EA09 by 14 deg in spw 2 and -23 deg in spw 3, and for
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| − | antenna EA10 by -130 deg in spw 2 and 145 deg in spw 3.
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| − | | |
| − | gencal(vis='test.ms',caltable='test.G',caltype='sbd',
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| − | spw='2,3',antenna='EA09,EA10',pol='',
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| − | parameter=[14,-23,-130,145])
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| − | | |
| − | --> Delay corrections in both polarizations will be adjusted for
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| − | antenna EA09 by 14 nsec in spw 2 and -23 nsec in spw 3, and for
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| − | antenna EA10 by -130 nsec in spw 2 and 145 nsec in spw
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| − | 3. See the above example for caltype='ph' for details
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| − | of the sign convention adopted when applying delay corrections.
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| − | | |
| − | gencal(vis='test.ms',caltable='test.G',caltype='antpos',
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| − | antenna='EA09,EA10',
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| − | parameter=[0.01,0.02,0.03, -0.03,-0.01,-0.02])
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| − | | |
| − | --> Antenna position corrections in meters (in ITRF) for
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| − | antenna EA09 (dBx=0.01, dBy=0.02, dBz=0.03) and for
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| − | antenna EA10 (dBx=-0.03, dBy=-0.01, dBz=-0.02)
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| − | See the above example for caltype='ph' for details
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| − | of the sign convention adopted when applying antpos
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| − | corrections.
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| − | gencal(vis='test.ms',caltable='test.G',caltype='antposvla',
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| − | antenna='EA09,EA10',
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| − | parameter=[0.01,0.02,0.03, -0.03,-0.01,-0.02])
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| − | | |
| − | --> Antenna position corrections (in the traditional VLA-centric
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| − | frame) will be introduced in meters for
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| − | antenna EA09 (dBx=0.01, dBy=0.02, dBz=0.03) and for
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| − | antenna EA10 (dBx=-0.03, dBy=-0.01, dBz=-0.02)
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| − | These offsets will be rotated to the ITRF frame before
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| − | storing them in the caltable.
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| − | See the above example for caltype='ph' for details
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| − | of the sign convention adopted when applying antpos
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| − | corrections.
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| − | </pre>
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