AIPS HELP file for DOPOL in 31DEC25
As of Wed Dec 11 5:21:23 2024
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:
BLPOLCAL......Do BLCHN for I, Q, U, V models
LINIMAGE......Build image cube from multi-IF data set.
Tasks:
ACIMG.........Makes image of autocorrelation data showing time vs
frequency.
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.
AVGWT.........Computes the average visibility weight of the included
data.
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.
BLPCL.........Do divide by I,Q,U models for circular polarization
BLCHN.
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.
CLOSE.........Plots closure phase or amplitude spectra averaged over
closures.
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.
RIRMS.........Computes rms of real/imag of a selected subset of a uv
data set.
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.
VH2RL.........Converts from linear to circular polarization and vice
versa.
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