AIPS HELP file for DFTPL in 31DEC24
As of Fri Apr 26 22:10:13 2024
DFTPL: Plots the DFT of an arbitrary point using UV data
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 9.0 Input UV file disk unit #
UVRANGE 0.0 Range of projected spacings
(thousands of wavelengths)
TIMERANG Time range to select:
Start Day, Hour, Min, Sec
End Day, Hour, Min, Sec
SHIFT Shift in asec at ref position
STOKES I, Q, U, V, RR, LL, VV, HH
BPARM Control parameters
1 : X axis type: 0, 1 -> time
2 : averaging interval (sec)
3 : > 0.0 => fixed scale
< 0.0 => fixed range
4 : Xmin (fixed scale)
5 : Xmax (fixed scale)
6 : Ymin (fixed scale)
7 : Ymax (fixed scale)
8 : X/Y axis ratio
9 : 1 plots points only
2 plots points and
error bars
3 plots histogram
10 : scale factor for points
SRCNAME Source name
QUAL -10.0 Calibrator qualifier -1=>all
CALCODE Calibrator code ' '=>all
SELBAND Bandwidth to select (kHz)
SELFREQ Frequency to select (MHz)
FREQID 0.0 Frequency ID number: 0 -> 1
SUBARRAY 0.0 1000.0 Sub-array, 0=>all
BIF 0.0 First IF to include
EIF 0.0 Last IF to include
BCHAN 0.0 First channel to include
ECHAN 0.0 Last channel to include
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.
DOCIRCLE -1.0 1.0 > 0 => extend ticks to form
coordinate grid
PRTLEV -1.0 > 0 => print time, flux, and
error to message file
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.
BADDISK Disks to avoid for scratch
HELP SECTION
DFTPL
Type: Task
Use: Plots the DFT of the complex visibilities found in a UV data
base for an arbitrary point in the sky as a function of time.
Note that the visibilies are shifted under control of SHIFT and
then the real parts are simply summed over all baselines in each
time interval. Task TBAVG makes a UV data set of the summed
visibilities instead of plotting them.
NOTE: This task does NOT apply any flag or calibration tables.
Run SPLIT or other appropriate task before running DFTPL.
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.
UVRANGE....Range (min, max) of projected baselines to include
0,0 => all baselines
TIMERANG...Time range of the data to be plotted. In order:
Start day, hour, min, sec, End day, hour, min, sec.
Days relative to reference date. 0 => full range.
SHIFT......Shift in arcseconds - the data are shifted, summed, and
then plotted. These are shifts in arc seconds at the
reference point -
RA = RA0 + SHIFT(1)/cos(DEC0), DEC = DEC0 + SHIFT(2)
STOKES.....Only one Hermitian polarization is allowed: I, Q, U, V,
RR, LL, VV, HH. Cross-hands do not have the Hermitian
property and so are not allowed.
BPARM......Control parameters:
1 = X axis type: <= 0, > 6 -> 1
(1) = Data label time
(2) = Antenna elevation
(3) = Hour angle
(4) = Local Sidereal Time
(5) = Parallactic angle
(6) = Antenna azimuth
These are defined wrt antenna 1; they really should only be
used with non-VLB arrays.
2 = averaging interval in seconds (0 => 60)
NOTE: an interval beginning at a sample time T1 will include
all samples < T1+BPARM(2). If your data occur at 5 second
intervals and you want no averaging, set BPARM(2) < 5. If
you want to average pairs of samples, set 5 < BPARM(2) < 10.
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, fully self-scaling.
4 = Minimum of X-axis. Units = days.
5 = Maximum of X-axis (if = BPARM(4) do self-scale in X).
6 = Minimum of Y-axis. Units = Jy.
7 = Maximum of Y-axis (if = BPARM(6) do self-scale in Y).
8 = Ratio of X axis length to Y axis length.
9 = If 1, simply plot up the point
-1, plot points and print out results (0 => -1)
If 2, plot points and error bars
-2, plot points, error bars, and print out results
If 3, plot points in histogram form
-3, plot histogram and print out results
SRCNAME....Source to be copied. ' '=> all. NOTE: this task makes
sense only if you select a single source.
QUAL.......Qualifier of source to be processed. -1 => all.
CALCODE....Calibrator code of source to be processed. ' '=> all.
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 process. 0=>all (okay if not
calibration)
BIF........Also average IFs BIF-EIF; 0 -> 1
EIF........Also average IFs BIF-EIF; 0 -> max
BCHAN......Average channels BCHAN-ECHAN; 0 -> 1
ECHAN......Average channels BCHAN-ECHAN; 0 -> max
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).
DOCIRCLE...False (<= 0) means that tick marks are short lines
extending inward from the plot borders. True (>0)
requests that a full coordinate grid be drawn.
PRTLEV.....> 0 -> print time, flux, and dispersion to message file.
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.
BADDISK....The disk numbers to avoid for scratch files (sorting
tables mostly).
EXPLAIN SECTION
DFTPL: Plots DFT using data from a u,v data base.
PROGRAMMER: T.Bastian, Univ. of Colorado
RELATED PROGRAMS: TKPL, LWPLA, TVPL
COMMENTS
DFTPL was written primarily to assist stellar observers
interested in time variable phenomena (e.g., outbursts on RS CVn's,
dMe flare stars, etc.). Since these stars are in general unresolved,
it's often pointless to make a synthesis map for each time interval.
Instead one can do the following: 1) make a large field map using the
entire XY sorted data base and identify all background sources; 2) run
APCLN or IMAGR with boxes around these sources (but not the stellar
source of interest) and CLEAN them down to the noise; 3) using the
resulting CLEAN components as a model of the background sources, use
UVSUB to subtract the model from the UV data base; 4) use UVSRT to
sort the data into TB order.
If NO confusing sources of any importance can be found in the
field, then of course steps 1-4 can be skipped and one simply begins
with a TB sorted (calibated and edited) data base. he UV data base on
an EXPORT tape is sorted in TB order, but one might have to use the
verb PUTHEAD to indicate this fact in the header. This is done by
first setting KEYWORD to 'SORT' and KEYSTRING to 'TB' and typing PUTH.
The task DFTPL allows one to plot the direct fourier transform
of the measured visibilities as a function of time for an arbitrary
shift in RA and DEC. It will plot either points, points with error
bars, or histogram format. The averaging interval is adjustable
(BPARM(2)). The data time segment may be specified (through APARM).
The task runs somewhat faster than UVPLT. Hence one can moniter all
Stoke's parameters of a star with time VERY quickly, without having to
resort to generating a tedious sucession of maps.