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NRAO Home > CASA > CASA Task Reference Manual |
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0.1.5 blcal
Requires:
Synopsis
Calculate a baseline-based calibration solution (gain or bandpass)
Description
Arguments
Inputs |
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vis |
| Name of input visibility file
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| allowed: | string |
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| Default: |
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caltable |
| Name of output gain calibration table
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| allowed: | string |
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| Default: |
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field |
| Select field using field id(s) or field name(s)
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| allowed: | string |
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| Default: |
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spw |
| Select spectral window/channels
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| allowed: | string |
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| Default: |
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intent |
| Select observing intent
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| allowed: | string |
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| Default: |
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selectdata |
| Other data selection parameters
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| allowed: | bool | |
| Default: | True |
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timerange |
| Select data based on time range
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| allowed: | string |
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| Default: |
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uvrange |
| Select data within uvrange (default units meters)
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| allowed: | any |
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| Default: | variant
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antenna |
| Select data based on antenna/baseline
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| allowed: | string |
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| Default: |
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scan |
| Scan number range
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| allowed: | string |
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| Default: |
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observation |
| Select by observation ID(s)
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| allowed: | any |
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| Default: | variant
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msselect |
| Optional complex data selection (ignore for now)
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| allowed: | string |
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| Default: |
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solint |
| Solution interval
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| allowed: | any |
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| Default: | variant inf |
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combine |
| Data axes which to combine for solve (obs, scan, spw,
and/or field)
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| allowed: | string |
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| Default: | scan |
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freqdep |
| Solve for frequency dependent solutions
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| allowed: | bool |
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| Default: | False |
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calmode |
| Type of solution” (’ap’, ’p’, ’a’)
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| allowed: | string |
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| Default: | ap |
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solnorm |
| Normalize average solution amplitudes to 1.0
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| allowed: | bool |
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| Default: | False |
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gaintable |
| Gain calibration table(s) to apply on the fly
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| allowed: | stringArray |
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| Default: |
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gainfield |
| Select a subset of calibrators from gaintable(s)
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| allowed: | stringArray |
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| Default: |
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interp |
| Interpolation mode (in time) to use for each gaintable
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| allowed: | stringArray |
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| Default: |
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spwmap |
| Spectral windows combinations to form for gaintables(s)
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| allowed: | intArray |
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| Default: |
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parang |
| Apply parallactic angle correction
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| allowed: | bool |
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| Default: | False |
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This task determines a baseline by baseline gain (time) or bandpass (freq)
for all baseline pairs in the data set. For the usual antenna-based calibration
of interferometric data, this task gaincal is recommended, even with only one
to three baselines. For arrays with closure errors, use blcal
Keyword arguments:
vis -- Name of input visibility file
default: none; example: vis=’ngc5921.ms’
caltable -- Name of output Gain calibration table
default: none; example: caltable=’ngc5921.gcal’
--- Data Selection (see help par.selectdata for more detailed information)
field -- Select field using field id(s) or field name(s).
[run listobs to obtain the list id’s or names]
default: ’’=all fields
If field string is a non-negative integer, it is assumed a field index
otherwise, it is assumed a field name
field=’0~2’; field ids 0,1,2
field=’0,4,5~7’; field ids 0,4,5,6,7
field=’3C286,3C295’; field named 3C286 adn 3C295
field = ’3,4C*’; field id 3, all names starting with 4C
spw -- Select spectral window/channels
default: ’’=all spectral windows and channels
spw=’0~2,4’; spectral windows 0,1,2,4 (all channels)
spw=’<2’; spectral windows less than 2 (i.e. 0,1)
spw=’0:5~61’; spw 0, channels 5 to 61
spw=’0,10,3:3~45’; spw 0,10 all channels, spw 3, channels 3 to 45.
spw=’0~2:2~6’; spw 0,1,2 with channels 2 through 6 in each.
spw=’0:0~10;15~60’; spectral window 0 with channels 0-10,15-60
spw=’0:0~10,1:20~30,2:1;2;3’; spw 0, channels 0-10,
spw 1, channels 20-30, and spw 2, channels, 1,2 and 3
intent -- Select observing intent
default: ’’ (no selection by intent)
intent=’*BANDPASS*’ (selects data labelled with
BANDPASS intent)
selectdata -- Other data selection parameters
default: True
timerange -- Select data based on time range:
default = ’’ (all); examples,
timerange = ’YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’
Note: if YYYY/MM/DD is missing dat defaults to first day in data set
timerange=’09:14:0~09:54:0’ picks 40 min on first day
timerange= ’25:00:00~27:30:00’ picks 1 hr to 3 hr 30min on next day
timerange=’09:44:00’ data within one integration of time
timerange=’>10:24:00’ data after this time
uvrange -- Select data within uvrange (default units kilo-lambda)
default: ’’ (all); example:
uvrange=’0~1000klambda’; uvrange from 0-1000 kilo-lambda
uvrange=’>4klambda’;uvranges greater than 4 kilo lambda
uvrange=’0~1000km’; uvrange in kilometers
antenna -- Select data based on antenna/baseline
default: ’’ (all)
If antenna string is a non-negative integer, it is assumed an antenna index
otherwise, it is assumed as an antenna name
antenna=’5&6’; baseline between antenna index 5 and index 6.
antenna=’VA05&VA06’; baseline between VLA antenna 5 and 6.
antenna=’5&6;7&8’; baseline 5-6 and 7-8
antenna=’5’; all baselines with antenna 5
antenna=’5,6,10’; all baselines with antennas 5 and 6
scan -- Scan number range - New, under developement
observation -- Observation ID(s).
default: ’’ = all
example: ’0~2,4’
msselect -- Optional complex data selection (ignore for now)
solint -- Solution interval (units optional)
default: ’inf’ (~infinite, up to boundaries controlled by combine);
Options: ’inf’ (~infinite), ’int’ (per integration), any float
or integer value with or without units
examples: solint=’1min’; solint=’60s’, solint=60 --> 1 minute
solint=’0s’; solint=0; solint=’int’ --> per integration
solint-’-1s’; solint=’inf’ --> ~infinite, up to boundaries
enforced by combine
combine -- Data axes to combine for solving
default: ’scan’ --> solutions will break at obs, field, and spw boundaries,
but may extend over multiple scans (per obs, field, and spw) up
to solint.
Options: ’’,’obs’,’scan’,’spw’,field’, or any comma-separated
combination in a single string
example: combine=’scan,spw’ --> extend solutions over scan boundaries
(up to the solint), and combine spws for solving
freqdep -- Solve for frequency dependent solutions
default: False (gain; True=bandpass); example: freqdep=True
calmode -- Type of solution
default: ’ap’ (amp and phase); example: calmode=’p’
Options: ’p’,’a’,’ap’
solnorm -- Normalize solutions. For freqdep=F, this is a global (per-spw)
normalization of amplitudes (only). For freqdep=T, each baseline
solution spectrum is separately normalized by its (complex) mean.
default: False (no normalization)
gaintable -- Gain calibration table(s) to apply
default: ’’ (none);
examples: gaintable=’ngc5921.gcal’
gaintable=[’ngc5921.ampcal’,’ngc5921.phcal’]
gainfield -- Select a subset of calibrators from gaintable(s)
default:’’ ==> all sources in table;
’nearest’ ==> nearest (on sky) available field in table
otherwise, same syntax as field
example: gainfield=’0~3’
gainfield=[’0~3’,’4~6’]
interp -- Interpolation type (in time[,freq]) to use for each gaintable.
When frequency interpolation is relevant (B, Df, Xf),
separate time-dependent and freq-dependent interp
types with a comma (freq _after_ the comma).
Specifications for frequency are ignored when the
calibration table has no channel-dependence.
Time-dependent interp options ending in ’PD’ enable a
"phase delay" correction per spw for non-channel-dependent
calibration types.
For multi-obsId datasets, ’perobs’ can be appended to
the time-dependent interpolation specification to
enforce obsId boundaries when interpolating in time.
default: ’’ --> ’linear,linear’ for all gaintable(s)
example: interp=’nearest’ (in time, freq-dep will be
linear, if relevant)
interp=’linear,cubic’ (linear in time, cubic
in freq)
interp=’linearperobs,spline’ (linear in time
per obsId,
spline in freq)
interp=’,spline’ (spline in freq; linear in
time by default)
interp=[’nearest,spline’,’linear’] (for multiple gaintables)
Options: Time: ’nearest’, ’linear’
Freq: ’nearest’, ’linear’, ’cubic’, ’spline’
spwmap -- Spectral windows combinations to form for gaintable(s)
default: [] (apply solutions from each spw to that spw only)
Example: spwmap=[0,0,1,1] means apply the caltable solutions
from spw = 0 to the spw 0,1 and spw 1 to spw 2,3.
spwmap=[[0,0,1,1],[0,1,0,1]]
parang -- If True, apply the parallactic angle correction (required
for polarization calibration)
default: False
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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