Spectral-line case

Version 1.9 Build 803

News	FAQ
Search	Home

Next: Instrumental Polarization Calibration Up: Correct the data Previous: Continuum polarimetry case

Spectral-line case

In the calibrater tool, select source & gain calibrators (Fields 2 & 3), reset the tool state, set up to apply flux-scaled gain solutions derived from the gain calibrator (Field 2) along with the bandpass solutions, and then correct the observed data, writing the result to the CORRECTED_DATA column in the measurement set:

calS.setdata(msselect='FIELD_ID IN [2,3]');  # Select sources in MS fields 
                                             #  2, & 3 to which calibration  
                                             #  is to be applied 
calS.reset();                                # Reset setapply/setsolve
calS.setapply(type='G',                      # Arrange to apply flux-scaled G 
              t=0.0,                         #  solutions (from field 2) from 
              table='ngc5921.fluxcal',       #  the ngc5921.fluxcal table.
              select='FIELD_ID==2');
calS.setapply(type='B',                      # Arrange to apply B solutions
              t=0.0,                         #  from the ngc5921.bcal table.
              table='ngc5921.bcal',
              select='');   
calS.state();                                # Review setapply settings
calS.correct();                              # Apply solutions and write the
                                             #  CORRECTED_DATA column in the MS.

The calibrator.state and calibrator.correct functions will produce the logger messages:

  The following calibration components will be applied:
    B table=ngc5921.bcal t=0 select=[]
    G table=ngc5921.fluxcal t=0 select=[(FIELD_ID+1)==2]
  The following calibration components will be solved for:
    None.
  Applying B table from ngc5921.bcal
  Applying G table from ngc5921.fluxcal

At this point, it is a good idea to examine the calibrated source data (CORRECTED_DATA column) with msplot and flag any bad data. The spectral line data set doesn't have any bad source data so this step will be skipped.

Note: The flux calibrator (3C 286, FIELD_ID 1) could have been calibrated at the same time by selecting it in the initial calS.setdata and applying the G and B solutions to all the data (as in the previous example with the continuum data set). To calibrate the 3C 286 data separately, execute calS.setdata and calS.setapply(type=G) again with FIELD_ID==1 selected in both, followed by calS.correct.

Next: Instrumental Polarization Calibration Up: Correct the data Previous: Continuum polarimetry case Contents