AIPS HELP file for CAPLT in 31DEC24
As of Wed Apr 24 22:10:30 2024
CAPLT: Plots closure amplitides from uv data base and model
INPUTS
USERID -32000.0 32000.0 File owner number - ignored
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK 0.0 3.0 Input UV file disk unit #
IN2NAME Input CC file name (name)
' ' => no model
IN2CLASS Input CC file name (class)
' ' => no model
IN2SEQ 0.0 9999.0 Input CC file name (seq. #)
IN2DISK 0.0 3.0 Input CC file disk unit #
IN2VERS 0.0 46655.0 Input CC file version #
NCOMP # comps to use for model.
1 value per field
FLUX Lowest CC component used.
NMAPS -4096.0 4096.0 # clean maps (fields).
0 => no model
Data selection:
NPOINTS 0 1000.0 Number points used when
NMAPS < 0.
SRCNAME Source name.
QUAL -10.0 Source qualifier -1=>all
CALCODE Calibrator code ' '=>all
SELBAND Bandwidth to select (kHz)
SELFREQ Frequency to select (MHz)
FREQID Freq. ID to select.
BCHAN 0.0 4096.0 Low channel # averaged 0=>1
ECHAN 0.0 4096.0 High channel # averaged
BIF 0.0 100.0 Low IF # averaged 0=>1
EIF 0.0 100.0 High IF # averaged 0=>max
XINC 0.0 9999.0 Plot every XINC'th visibility
0 => 1
UVRANGE 0.0 Range of projected spacings
(thousands of wavelengths)
TIMERANG Time: start day,hr,min,sec
stop day,hr,min,sec.
STOKES Stokes' parameter: only 1
TRIANGLE Closure quadrangles to plot
See HELP.
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 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 apply bandpass cal.
Method used depends on value
of DOBAND (see HELP file).
BPVER Bandpass table version
SMOOTH Smoothing function. See
SUBARRAY Subarray number 0=all.
DOEBAR If > 0, plot error bars,
else don't
SOLINT Time interval over which to
average data in order to
form closure amplitude (mins)
See HELP for hints on how
to use this.
OPCODE If OPCODE = 'INDE' will plot
all independent closure
amplitudes.
If OPCODE = ' ' will plot all
closure amplitudes, or all
closure amplitudes specified
by the TRIANGLE adverb.
See HELP for more info.
BPARM Control parameters
1 : 1 => x-axis is UTC
or IAT (depending on
time system in data.)
: 2 => x-axis is GST
0 => 1
2 : not used
3 : >0.0 => fixed scale
<0.0 => fixed range
0.0 => sep. scales
4 : Xmin (fixed scale)
5 : Xmax (fixed scale)
6 : Ymin (fixed scale)
7 : Ymax (fixed scale)
8 : Max no. plots/page.
9 > 0 -> plot models for
baselines with no data
10: unused
SYMBOL 0.0 24.0 Symbol to use when plotting.
0 => Vertical line
1 - 24, standard types
FACTOR 0.0 1000.0 Scale symbol plotted
LTYPE -410.0 410.0 Type of labeling: 1 border,
2 no ticks, 3 - 6 standard,
7 - 10 only tick labels
<0 -> no date/time
DOTV -1.0 1.0 > 0 Do plot on the TV, else
make a plot file
GRCHAN 0.0 8.0 Graphics channel 0 => 1.
XYRATIO 0.0 X/Y ratio 0 -> fit TV or 1 PL
BADDISK Disks to avoid for scratch
HELP SECTION
CAPLT
Type: Task
Use: Plots closure amplitude from a u,v data base making a plot file
or using the TV. Also, if a valid CLEAN map is specified the
model values will be plotted. Plotting is done one quadrangle
(4 antennas) per plot with the number of plots per page
specified by BPARM(8). The plots are written one page per plot
file so in general several plot files will be created. Model
types recognized are: points, elliptical gaussians and uniform
spheres. The DO3DIMAG option of IMAGR is fully supported as are
multi-scale images.
If the fringe rate for the source is fairly rapid, then it is very
important to have the sampling be the same on all baselines in
each quadrangle. Otherwise, samples at slightly different times
will be combined but the amplitudes will not cancel properly.
Use of a very small value of SOLINT (but > 0) will cause
inadequately aligned data to be discarded in order to avoid
misleadingly high closure amplitudes.
Note that you might wish to divide your data by your model with
OOSUB or UVSUB, and then plot the closure amplitudes from the
resulting "gains".
Closure amplitude in the quadrangle of antennas a, b, c, and d is
defined as
LN [ (amp_ab * amp_cd) / (amp_ac * amp_bd) ]
which should be independent of any antenna-based instrumental
gains. Since these apply to the RR and LL, closure phase is only
meaningful in the STOKES 'RR', 'LL', 'VV', and 'HH'. CAPLT will
allow you to select any single Stokes however, although most are
not meaningful.
Closure information is produced by the following tasks:
CLPLT Plots closure phases for individual triangles as a
funtion of time.
CAPLT Plots closure amplitudes for individual quadrangles as
a funtion of time.
EVACL Computes the RMS of closure phase and amplitude as a
function of IF for an individual Stokes.
EVAUV Computes two data sets: data-model and data/model. The
closure RMSes of the latter may be computed as
functions of polarization and IF. Other statistics
are computed and plotted.
CLOSE Computes the RMS closure phase or amplitude as a
function of spectral and IF channel. A plot is
produced and a text file may be written.
Adverbs:
USERID.....Input file user number. Ignored
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.
IN2NAME....Name of desired CLEAN components to be used. If this file
is not found no model will be plotted ' ' => no model.
IN2CLASS...Class of CLEAN map. ' ' => no model
IN2SEQ.....Sequence number of CLEAN map. 0 => highest.
IN2DISK....Disk number of CLEAN map. 0 => any.
IN2VERS....CLEAN component file version (CC tables) 0 => highest.
The same version number is used for the all selected
image files. Use task TACOP to provide the same numbers
for desired CC tables.
For a multi-source file, the flux of the clean components
selected for the model are summed and scaled to the source
flux found in the SU table. If that flux is zero, no
scaling is done.
NCOMP......Number of Clean components to use for the model, one
value per field. If all values are zero, then all
components in all fields are used. If any value is not
zero, then abs(NCOMP(i)) (or fewer depending on FLUX and
negativity) components are used for field i, even if
NCOMP(i) is zero. If any of the NCOMP is less than 0,
then components are only used in each field i up to
abs(NCOMP(i)), FLUX, or the first negative whichever
comes first. If abs(NCOMP(i)) is greater than the number
of components in field i, the actual number is used. For
example
NCOMP = -1,0
says to use one component from field one unless it is
negative or < FLUX and no components from any other
field. This would usually not be desirable.
NCOMP = -1000000
says to use all components from each field up to the
first negative in that field.
NCOMP = -200 100 23 0 300 5
says to use no more than 200 components from field 1, 100
from field 2, 23 from field 3, 300 from field 5, 5 from
field 6 and none from any other field. Fewer are used if
a negative is encountered or the components go below
FLUX. *** This option is limited to the first 200000
Clean components encountered. ***
FLUX.......Only components > FLUX in absolute value are used in the
model.
NMAPS......Number of image files to use for model. For multi-scale
models, set NMAPS = NFIELD * NGAUSS to include the Clean
components of the extended resolutions. If more than one
file is to be used, the NAME, CLASS, DISK and SEQ of the
subsequent image files will be the same as the first file
except that the LAST 3 or 4 characters of the CLASS will
be an increasing sequence above that in IN2CLASS. Thus,
if INCLASS='ICL005', classes 'ICL005' through 'ICLnnn'
or 'ICnnnn', where nnn = 5 + NMAPS - 1 will be used. Old
names (in which the 4'th character is not a number) are
also supported: the last two characters are '01' through
'E7' for fields 2 through 512. In old names, the highest
field number allowed is 512; in new names it is 4096.
= 0 => do not plot a model
> 0 => plot the model at each data sample. In this mode,
the u,v,w are known from the data sample, but the
sampling for each baseline may be coarse and
irregular.
< 0 => plot a model at 200 regularly sampled points for
each baseline. In this mode, the u,v,w's are
computed from the times and antenna locations and
may have subtle (or not so subtle) complications
(with precession, u-v rotation, times) causing the
plotted model to fail to match the plotted data.
NPOINTS....Number model points when NMAPS<0. < 200 -> 200.
Max is 1000.
SRCNAME....Source name. If the data is a multi-source file, CLPLT
will plot the visibility for the source specified. If the
data is a single source file no source name need be
specified.
QUAL.......Only sources with a source qualifier number in the
SU table matching QUAL will be used if QUAL is not
-1.
CALCODE....Calibrators may be selected on the basis of the
calibrator code:
' ' => any calibrator code selected
'* ' => any non blank code (cal. only)
'-CAL' => blank codes only (no calibrators)
anything else = calibrator code to select.
NB: The CALCODE test is applied in addition to the
other tests, i.e. CALSOUR and QUAL, in the
selection of sources for which to determine
solutions.
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, 0=> all
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, 0=> all
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 overide that of FREQID,
however setting SELBAND and SELFREQ may occasionally
result in an ambiguity, in which case the task will
request that you use FREQID.
BCHAN......Start channel. 0 => 1
ECHAN......End channel. 0 => max The data from BCHAN through ECHAN
will be averaged before plotting.
BIF........Start IF number to plot. 0 => 1
EIF........End IF number to plot. 0 => max The data from BIF
through EIF will be averaged before plotting.
XINC.......Plot every XINC'th visibility
which might be plotted. 0 => 1
UVRANGE....Range (min, max) of projected baselines to include
0,0 => all baselines
TIMERANG...The specified time range.
1 = Start IAT day (day 0 = first day in data base)
2 = Start IAT hour
3 = Start IAT minute
4 = Start IAT second
5 = Stop IAT day (day 0 = first day in data base)
6 = Stop IAT hour
7 = Stop IAT minute
8 = Stop IAT second
stop IAT = 0 => beginning
stop IAT = 0 => end.
of time.
STOKES.....Specifies the single Stokes type to be plotted:
Recognized values are 'I', 'Q', 'U', 'V', 'RR', 'LL', 'LR',
'RL', 'VV', 'HH', 'VH', 'HV'. ' ' => 'I'.
TRIANGLE...A list of the closure quadrangles to be plotted.
(a) If TRIANGLE = 0, CLPLT will plot all available closure
amplitudes.
(b) If TRIANGLE(1) < 0, then CLPLT will plot all available
closure amplitudes, EXLUDING those quadrangles
involving antennas listed in the TRIANGLE array (with
either sign)
(c) If you wish to plot specified quadrangles you should
specify them as quadruplets within the TRIANGLE
array. E.g. TRIANGLE=1,2,3,4,2,5,6,8 will cause
CLPLT to plot quadrangles 1-2-3-4 and 2-5-6-8. You may
specify up to 12 quadrangles in this manner.
IF OPCODE = 'INDE' and TRIANGLE = 0 then CLPLT will plot
all independent closure quadrangles, if TRIANGLE is
non-zero the task will complain.
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
multisource 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 appply. <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.
BPVER......Specifies the version of the BP table to be either
plotted (if APARM(8)=2) or applied (if DOBAND > 0
and APARM(8) .NE. 2). 0 => highest numbered table.
<0 => no bandpass correction to be applied.
plotted (if APARM(8)=2) or applied (if DOBAND > 0
and APARM(8) .NE. 2). 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).
SUBARRAY...The subarray number desired. 0=> all.
DOEBAR.....If = 0 => do not plot error bars on data
if = 1 => do plot error bars
This works only if the data weights are in fact 1/sigma^2
with the sigma on the same scale as the visibilities.
Data weights that are simply the count of integration
time (or some such) will not give valid error bars.
OPCODE.....If OPCODE = ' ' then plot closure amplitude vs. time
obeying the TRIANGLE adverb. If OPCODE = 'INDE' then all
independent quadrangles are plotted.
BPARM......Control parameters:
1 = limited types of x-axis values available.
1 = time (UT or IAT, depending on timesystem in use)
2 = GST
0 - default => 1
2 = not used
3 = if greater than zero, use BPARM(4) - BPARM(8) as the
ranges of the axes. If less than zero, use the BPARMs
to limit the range of the axes, but self-scale the axes
within that range. If 0.0, scale the Y axis separately
for each baseline.
4 = Minimum of X-axis.
5 = Maximum of X-axis (if = BPARM(4) do self-scale in X).
6 = Minimum of Y-axis. See note below on units.
7 = Maximum of Y-axis (if = BPARM(6) do self-scale in Y).
8 = Maximum number of plots per page: 0 => 3
9 = Control of plotting for baselines with no data samples:
> 0 => plot such baselines if a model is being plotted
<= 0 => don't plot them - such baselines are never
plotted if there is not a model being plotted.
10 = No longer used
SOLINT.....The time interval (minutes) over which to average the data
in order to form the closure amplitude. It is possible,
especially on correlators which only correlate a subset of
the available stations simultaneously that the time tags
associated with visibility values on different baselines
differ. Therefore one has to specify a time interval over
which to average the data to form the closure amplitude.
If this is not necessary with your data, set
0 < SOLINT <= 0.9 * data integration time.
You should experiment a little with this parameter. If the
fringe rate for the source is fairly rapid, then it is very
important to have the sampling be the same on all baselines
in each quadrangle. Otherwise, samples at slightly
different times will be combined but the amplitudes will
not cancel properly. Use of a very small value of SOLINT
(but > 0) will cause inadequately aligned data to be
discarded in order to avoid misleadingly high closure
phases.
If SOLINT < 0, the task will form a closure amplitude as
soon as it has accumulated at least one sample for each
of the four baselines in the quadrangle. The closure
amplitudes will then be averaged over SOLINT minutes.
This averaging is a scalar averaging and may be
particularly affected by Ricean noise bias.
SYMBOL.....Symbol to use when plotting.
1: Plus sign 13: Star of David
2: Cross (X) 14: Seven-pointed star
3: Circle 15: Eight-pointed star
4: Box 16: Nine-pointed star
5: Triangle 17: Ten-pointed star
6: Diamond 18: 11-pointed star
7: Pentagon 19: 12-pointed star
8: Hexagon 20: 13-pointed star
9: Septagon 21: 14-pointed star
10: Octagon 22: Plus (+) with gap
11: Nine-gon 23: Cross (X) with gap
12: Five pointed star 24: Vertical line
If error bars are plotted, SYMBOL = 24 is recommended.
FACTOR......Scale plot symbol by FACTOR, 0 -> 1. FACTOR is applied
even when plotting error bars.
LTYPE.......Labelling type, see HELP LTYPE for details:
1 = border, 2 = no ticks, 3 or 7 = standard, 4 or 8 =
relative to ref. pixel, 5 or 9 = relative to subimage
(BLC, TRC) center, 6 or 10 = pixels. 7-10 all labels
other than tick numbers and axis type are omitted.
Less than 0 is the same except that the plot file
version number and create time are omitted.
Add n * 100 to alter the metric scaling.
DOTV........> 0 => plot directly on the TV device, otherwise
make a plot file for later display on one or
more devices (including the TV if desired).
GRCHAN......Graphics channel (1 - 7) to use for line drawing.
0 => 1.
XYRATIO.....Scale the X axis longer than the Y by XYRATIO.
If DOTV > 0, 0 -> fit to the TV window
If DOTV <= 0, 0 -> 1.
BADDISK....The disk numbers to avoid for scratch files (sorting
tables mostly).
EXPLAIN SECTION