AIPS HELP file for TRUEP in 31DEC25
As of Tue Feb 11 7:43:46 2025
TRUEP: determines true antenna polarization from special data
INPUTS
INNAME Normal UV file name (name)
INCLASS Normal UV file name (class)
INSEQ 0.0 9999.0 Normal UV file name (seq. #)
INDISK 0.0 9.0 Normal UV file disk unit #
IN2NAME Rotated UV file name
IN2CLASS Rotated UV file class
IN2SEQ 0.0 9999.0 Rotated UV file seq. #
IN2DISK 0.0 9.0 Rotated UV file disk #
SOURCES Source name: (1) first file
(2) second file, rest ignored
QUAL -10.0 Calibrator qualifier -1=>all
CALCODE Calibrator code ' '=>all
TIMERANG Time range to use
SELBAND Bandwidth to select (kHz)
SELFREQ Frequency to select (MHz)
FREQID Freq. ID to select.
SUBARRAY 0.0 1000.0 Sub-array, 0=>all
BIF Low IF number to do
EIF Highest IF number to do
BCHAN 0.0 First channel included
ECHAN 0.0 last channel included
DOCALIB -1.0 101.0 > 0 calibrate data & weights
> 99 do NOT calibrate weights
GAINUSE CL (or SN) table to apply
DOPOL -1.0 10.0 If >0.5 correct polarization.
PDVER PD table to apply (DOPOL>0)
BLVER BL table to apply.
FLAGVER Flag table version
DOBAND -1.0 10.0 If >0.5 apply bandpass cal.
Method used depends on value
of DOBAND (see HELP file).
BPVER Bandpass table version
SMOOTH Smoothing function. See
HELP SMOOTH for details.
SPECTRAL -1.0 1.0 > 0 => do a channel-dependent
solution
APARM (1) antenna that rotates
(2) rotation angle 0 -> 90
(3) = 1 -> display avg data
(ignored if SPECTRAL > 0)
(4) Freq smoothing type: 0 no
(5) Smoothing diameter
(6) Smoothing support
(7) HI file level, -1 none
BADDISK Disks to avoid for scratch
HELP SECTION
TRUEP
Task: This task will read the RL and LR data for one source from the
first data set and the RL and LR data for a second source from
the second data set. It is assumed that the second data set
has the horn of one antenna rotated by about 90 degrees. The
baselines to this antenna then allow the task to determine the
full polarization D terms for all antennas.
A continuum solution will be printed for each IF and the
averaged data may be displayed. A spectral solution will be
written to a new PD table which may then be plotted with POSSM.
Adverbs:
Data set with normal feed position
INNAME.....Input UV file name (name). Standard defaults.
INCLASS....Input UV file name (class). Standard defaults.
INSEQ......Input UV file name (seq. #). 0 => highest.
INDISK.....Disk drive # of input UV file. 0 => any.
Data set with rotated feed position
IN2NAME....Input UV file name (name). Standard defaults.
IN2CLASS...Input UV file name (class). Standard defaults.
IN2SEQ.....Input UV file name (seq. #). 0 => highest.
IN2DISK....Disk drive # of input UV file. 0 => any.
SOURCES....Source names to be used: SOURCE(1) for the first data set
and SOURCE(2) for the second data set. SOURCE(2) = ' '
=> SOURCE(2) = SOURCE(1)
QUAL.......Qualifier of source to be used. -1 => all.
CALCODE....Calibrator code of sources to use. ' '=> all.
TIMERANG...Time range of the data to be copied. In order: Start day,
hour, min. sec, end day, hour, min. sec. Days relative to
ref. date.
SELBAND....Bandwidth of data to be selected. If more than one IF is
present SELBAND is the width of the first IF required.
Units = kHz. For data which contain multiple
bandwidths/frequencies the task will insist that some form
of selection be made by frequency or bandwidth.
SELFREQ....Frequency of data to be selected. If more than one IF is
present SELFREQ is the frequency of the first IF required.
Units = MHz.
FREQID.....Frequency identifier to select (you may determine which is
applicable from the OPTYPE='SCAN' listing produced by
LISTR). If either SELBAND or SELFREQ are set, their values
override that of FREQID. However, setting SELBAND and
SELFREQ may result in an ambiguity. In that case, the task
will request that you use FREQID.
SUBARRAY...Sub-array number to copy. 0=>all.
BIF........First IF to include. 0 -> 1.
EIF........Last IF to include. 0 -> BIF. Give these if you want
task to loop over IF.
BCHAN......First channel to copy. 0=>all.
ECHAN......Highest channel to copy. 0=>all higher than BCHAN
Channels are averaged unless SPECTRAL > 0
DOCALIB....If true (>0), calibrate the data using information in the
specified Cal (CL) table for multi-source or SN table for
single-source data. Also calibrate the weights unless
DOCALIB > 99 (use this for old non-physical weights).
GAINUSE....version number of the CL table to apply to multi-source
files or the SN table for single source files.
0 => highest.
DOPOL......If > 0 then correct data for instrumental polarization as
represented in the AN or PD table. This correction is
only useful if PCAL has been run or feed polarization
parameters have been otherwise obtained. See HELP DOPOL
for available correction modes: 1 is normal, 2 and 3 are
for VLBI. 1-3 use a PD table if available; 6, 7, 8 are
the same but use the AN (continuum solution) even if a PD
table is present.
PDVER......PD table to apply if PCAL was run with SPECTRAL true and
0 < DOPOL < 6. <= 0 => highest.
BLVER......Version number of the baseline based calibration (BL) table
to apply. <0 => apply no BL table, 0 => highest.
FLAGVER....specifies the version of the flagging table to be applied.
0 => highest numbered table.
<0 => no flagging to be applied.
DOBAND.....If true (>0) then correct the data for the shape of the
antenna bandpasses using the BP table specified by BPVER.
The correction has five modes:
(a) if DOBAND=1 all entries for an antenna in the table
are averaged together before correcting the data.
(b) if DOBAND=2 the entry nearest in time (including
solution weights) is used to correct the data.
(c) if DOBAND=3 the table entries are interpolated in
time (using solution weights) and the data are then
corrected.
(d) if DOBAND=4 the entry nearest in time (ignoring
solution weights) is used to correct the data.
(e) if DOBAND=5 the table entries are interpolated in
time (ignoring solution weights) and the data are then
corrected.
IMAGR uses DOBAND as the nearest integer; 0.1 is therefore
"false".
BPVER......Specifies the version of the BP table to be applied
0 => highest numbered table.
<0 => no bandpass correction to be applied.
SMOOTH.....Specifies the type of spectral smoothing to be applied to
a uv database . The default is not to apply any smoothing.
The elements of SMOOTH are as follows:
SMOOTH(1) = type of smoothing to apply: 0 => no smoothing
To smooth before applying bandpass calibration
1 => Hanning, 2 => Gaussian, 3 => Boxcar, 4 => Sinc
To smooth after applying bandpass calibration
5 => Hanning, 6 => Gaussian, 7 => Boxcar, 8 => Sinc
SMOOTH(2) = the "diameter" of the function, i.e. width
between first nulls of Hanning triangle and sinc
function, FWHM of Gaussian, width of Boxcar. Defaults
(if < 0.1) are 4, 2, 2 and 3 channels for SMOOTH(1) =
1 - 4 and 5 - 8, resp.
SMOOTH(3) = the diameter over which the convolving
function has value - in channels. Defaults: 1,3,1,4
times SMOOTH(2) used when input SMOOTH(3) < net
SMOOTH(2).
SPECTRAL...Average spectral channels unless SPECTRAL > 0. In that
case, write a new PD table.
APARM......(1) Antenna having the rotated feed.
(2) Estimate of rotation angle. 0 => 90 degrees.
(3) = 1 => display averaged data also
(ignored if SPECTRAL > 0)
(4) Type of smoothing to apply after the fit
0 => no smoothing
1 => Hanning
2 => Gaussian
3 => Boxcar
4 => Sinc (i.e. sin(x)/x)
(5) Diameter in channels of the smoothing function:
i.e. width between first nulls of Hanning triangle
and sinc function, FWHM of Gaussian, width of Boxcar.
Defaults (if < 0.1) are 4, 2, 2 and 3 channels for
APARM(4) = 1 - 4.
(6) the diameter over which the convolving function has
value - in channels. Defaults: 1, 3, 1, 4 times
APARM(5) used when input APARM(6) < net APARM(5).
(7) History file writing control: < 0 none, 0 SPECTRAL
and APARM only . 0 all cal adverbs.
BADDISK....The disk numbers to avoid for scratch files (sorting
tables mostly).
EXPLAIN SECTION