Difference between revisions of "Blcal"

From CASA Guides
Jump to navigationJump to search
(Created page with '== Help on blcal task: == <pre> Calculate a baseline-based calibration solution (gain or bandpass) This task determines a baseline by baseline gain (time) or bandpass (…')
 
(Replaced content with "{{blcal}}")
 
(2 intermediate revisions by one other user not shown)
Line 1: Line 1:
== Help on blcal task: ==
+
{{blcal}}
 
 
<pre>
 
Calculate a baseline-based calibration solution (gain or bandpass)
 
 
 
        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
 
        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='0~1000kl'; uvrange from 0-1000 kilo-lamgda
 
              uvrange='>4kl';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
 
        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='1m'; 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 field and spw boundaries,
 
                        but may extend over multiple scans (per field and spw) up
 
                        to solint.
 
              Options: '','scan','spw',field', or any comma-separated combination
 
              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;
 
              same syntax as field
 
              example: gainfield='0~3'
 
                        but may extend over multiple scans (per field and spw) up
 
                        to solint.
 
              Options: '','scan','spw',field', or any comma-separated combination
 
              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;
 
              same syntax as field
 
              example: gainfield='0~3'
 
                        gainfield=['0~3','4~6']
 
        interp -- Interpolation mode (in time) to use for each gaintable
 
                default: '' --> 'linear' for all gaintable(s)
 
                example: interp='nearest'
 
                        interp=['nearest','linear']
 
                Options: 'nearest', 'linear', 'aipslin'
 
        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]]
 
        gaincurve -- Apply internal VLA antenna gain curve correction (True/False)
 
              default: False;
 
              Use gaincurve=True ONLY for VLA data
 
        opacity -- Opacity correction to apply (nepers)
 
              default: 0.0 (no opacity correction)
 
              example: opacity=0.051
 
              Typical VLA values are: 5 GHz - 0.013, 8 GHz - 0.013
 
              15 GHz - 0.016, 23 GHz - 0.051, 43 GHz - 0.07
 
        parang -- If True, apply the parallactic angle correction (required
 
              for polarization calibration)
 
              default: False
 
</pre>
 

Latest revision as of 19:24, 6 May 2015