AIPS NRAO AIPS HELP file for DOPOL in 31DEC21



As of Thu Jun 24 19:15:42 2021



HELP SECTION

DOPOL
Type: Adverb  (Scalar)
Use:  Standard data calibration adverb.  If > 0 then the uv-data will be
      corrected for the instrumental polarization response at each
      antenna, as stored in the antenna (AN) table. The following
      correction modes are available:
        (1) Apply the standard polarization and parallactic angle
            corrections. For the linear D-term approx., only first-order
            terms are retained.
      For 'VLBI' polarization solutions, two further modes are possible:
        (2) If DOPOL = 2, include 2nd order D-term coefficients when
            using the linear D-term approximation, and correct both
            parallel- and cross-hand data. Use approximations for
            missing polarization data when computing the correction
            matrices.
        (3) If DOPOL = 3, do as in (2), but apply rigorous flagging,
            excluding any output visibility data which have ANY missing
            polarization correlation pairs.
      To avoid use of a PD table when present, set DOPOL = 6, 7, or 8
      to get the action of 1, 2, or 3 with the AN file polarizations
      rather than the PD (spectral) polarizations.
Null value:  false (0) => do no polarization calibration .
Verbs:
   OBITIMAG......Access to OBIT task Imager without self-cal or peeling.
   OBITPEEL......Access to OBIT task Imager with self-cal and peeling.
   OBITSCAL......Access to OBIT task Imager with self-cal, NOT peeling.
Procedures:
   LINIMAGE......Build image cube from multi-IF data set.
Tasks:
   ACLIP.........Edits suto-corr data for amplitudes, phases, and weights
                 out of range.
   ACSCL.........Corrects cross amplitudes using auto correlation
                 measurements.
   ALVAR.........Plots the Allan Variance statistic of a UV data set.
   ALVPR.........Prints statistics on the Allan Variance of a UV data set.
   ANBPL.........Plots and prints uv data converted to antenna based
                 values.
   AVSPC.........Averages uv-data in the frequency domain.
   BLCAL.........Compute closure offset corrections.
   BLCHN.........Compute closure offset corrections on a
                 channel-by-channel basis.
   BLING.........Find residual rate and delay on individual baselines.
   BPASS.........Computes spectral bandpass correction table.
   BPWAY.........Determines channel-dependent relative weights.
   BPWGT.........Calibrates data and scales weights by bandpass
                 correction.
   BSCAN.........Seeks best scan to use for phase cal, fringe search, ..
   CALIB.........Determines antenna calibration: complex gain.
   CAPLT.........Plots closure amplitude and model from CC file.
   CLIP..........Edits data based on amplitudes, phases, and weights out
                 of range.
   CLPLT.........Plots closure phase and model from CC file.
   CORER.........Calculates correlator statistics and flags bad ones.
   CPASS.........Computes polynomial spectral bandpass correction table.
   DECOR.........Measures the decorrelation between channels and IF of uv
                 data.
   DEFLG.........Edits data based on decorrelation over channels and time.
   DFTIM.........Makes image of DFT at arbitrary point showing time vs
                 frequency.
   DFTPL.........Plots DFT of a UV data set at arbitrary point versus
                 time.
   DIFRL.........Divides the RR data by LL data.
   DTSUM.........Task to provide a summary of the contents of a dataset.
   EDITR.........Interactive baseline-oriented visibility editor using the
                 TV.
   EVAUV.........Subtracts & divides a model into UV data, does statistics
                 on results.
   FGCNT.........Counts samples comparing two flag tables.
   FGSPW.........Flags bad spectral windows.
   FINDR.........Find normal values for a uv data set.
   FLAGR.........Edit data based on internal RMS, amplitudes, weights.
   FLGIT.........Flags data based on the rms of the spectrum.
   FLOPM.........Reverses the spectral order of UV data, can fix VLA
                 error.
   FRING.........Fringe fit data to determine antenna calibration, delay,
                 rate.
   FRMAP.........Task to build a map using fringe rate spectra.
   FRPLT.........Task to plot fringe rate spectra.
   FTFLG.........Interactive flagging of UV data in channel-time using the
                 TV.
   FUDGE.........Modifies UV data with user's algorithm: paraform task.
   IBLED.........Interactive BaseLine based visibility EDitor.
   IMAGR.........Wide-field and/or wide-frequency Cleaning / imaging task.
   KRING.........Fringe fit data to determine antenna calibration, delay,
                 rate.
   LISTR.........Prints contents of UV data sets and assoc. calibration
                 tables.
   MAPBM.........Map VLA beam polarization.
   NOIFS.........Makes all IFs into single spectrum.
   OMFIT.........Fits sources and, optionally, a self-cal model to uv
                 data.
   PCAL..........Determines instrumental polarization for UV data.
   PHSRF.........Perform phase-referencing within a spectral line
                 database.
   POSSM.........Task to plot total and cross-power spectra.
   REWAY.........Computes weights based in rms in spectra.
   RFI...........Look for RFI in uv data.
   RFLAG.........Flags data set based on time and freq rms in fringe
                 visibilities.
   RLCAL.........Determines instrumental right-left phase versus time (a
                 self-cal).
   RLDIF.........Determines Right minus Left phase difference, corrects
                 cal files.
   RLDLY.........Fringe fit data to determine antenna R-L delay
                 difference.
   SCIMG.........Full-featured imaging plus self-calibration loop with
                 editing.
   SCMAP.........Imaging plus self-calibration loop with editing.
   SHOUV.........Displays uv data in various ways.
   SPFLG.........Interactive flagging of UV data in channel-TB using the
                 TV.
   SPLAT.........Applies calibration and splits or assemble selected
                 sources.
   SPLIT.........Converts multi-source to single-source UV files w
                 calibration.
   SPMOD.........Modify UV database by adding a model with spectral lines.
   SPRMS.........Plots spectral statistics of a selected subset of a uv
                 data set.
   SUFIX.........Modifies source numbers on uv data.
   TI2HA.........Modifies times in UV data to hour angles.
   TIORD.........Checks data for time baseline ordering, displays
                 failures.
   TRUEP.........Determines true antenna polarization from special data
                 sets.
   TVFLG.........Interactive flagging of UV data using the TV.
   UFLAG.........Plots and edits data using a uv-plane grid and the TV.
   UV2MS.........Append single-source file to multi-source file.
   UV2TB.........Converts UV autocorrelation spectra to tables.
   UVAVG.........Average or merge a sorted (BT, TB) uv database.
   UVBAS.........Averages several channels and subtracts from uv data.
   UVFIT.........Fits source models to uv data.
   UVFND.........Prints selected data from UV data set to search for
                 problems.
   UVFRE.........Makes one data set have the spectral structure of
                 another.
   UVGIT.........Fits source models to uv data.
   UVHGM.........Plots statistics of uv data files as histogram.
   UVHIM.........Makes image of the histogram on two user-chosen axes.
   UVHOL.........Prints holography data from a UV data base with
                 calibration.
   UVIMG.........Grid UV data into an "image".
   UVLIN.........Fits and removes continuum visibility spectrum, also can
                 flag.
   UVLSD.........Least squares fit to channels and divides the uv data.
   UVLSF.........Least squares fit to channels and subtracts from uv data.
   UVMLN.........Edits data based on the rms of the spectrum.
   UVMOD.........Modify UV database by adding a model incl spectral index.
   UVMTH......... Averages one data set and applied it to another.
   UVPLT.........Plots data from a UV data base in multiple ways.
   UVPRM.........Measures parameters from a UV data base.
   UVPRT.........Prints data from a UV data base with calibration.
   UVRFI.........Mitigate RFI by Fourier transform or fitting the circle.
   UVRMS.........Computes statistics of a selected subset of a uv data
                 set.
   VPLOT.........Plots uv data and model from CC file.
   WIPER.........Plots and edits data from a UV data base using the TV.
   XYDIF.........Find/apply X minus Y linear polarization phase
                 difference.
   XYMOD.........Compute linear polarization point source model, applies
                 to data.

EXPLAIN SECTION


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