AIPS HELP file for ACIMG in 31DEC25
As of Tue Dec 10 4:55:54 2024
ACIMG: Images autocorrelation data showing time vs frequency
INPUTS
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 #
OUTNAME Output MA file name (name)
OUTCLASS Output MA file name (class)
OUTSEQ 0.0 9999.0 Output MA file name (seq. #)
OUTDISK 0.0 9.0 Output MA file disk unit #
ANTENNAS Antennas to include
TIMERANG Time range to select:
Start Day, Hour, Min, Sec
End Day, Hour, Min, Sec
STOKES I, Q, U, V, RR, LL, VV, HH
also allowed RL, LR, VH, HV
BPARM Control parameters
2 : averaging interval (sec)
3 > 0 -> write error image
SOURCES 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
NCHAV 0.0 Number channels to average
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.
BADDISK Disks to avoid for scratch
HELP SECTION
ACIMG
Type: Task
Use: Makes an image of autocorrelation data found in a UV data base.
as a function of time and frequency. Task DFTIM makes this
sort of image for cross-correlation data, while TBAVG makes a UV
data set of the summed visibilities and DFTPL makes a plot of a
selected frequency range.
Adverbs:
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.
OUTNAME....Output name of image(name). Standard defaults.
OUTCLASS...Output name of image(class). Standard defaults.
OUTSEQ.....Output name of image(seq. #). 0 => highest unique
OUTDISK....Disk drive # of Output image. 0 => highest with space
ANTENNAS...List of antennas to include. 0 -> any. Note that the
task makes an ANTENNA axis making an image cube.
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.
STOKES.....Only one polarization is allowed: I, Q, U, V, RR, LL, VV,
HH. Cross-hands (RL, LR, VH, HV) are allowed but only
the real part is imaged.
BPARM......Control parameters:
1: unused
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 = > 0 -> write also an error image
4-10 unused
SOURCES....Source to be copied. ' '=> all; if any starts with a
'-' then all except ANY source named.
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........Start IF; 0 -> 1
EIF........End IF; 0 -> max
BCHAN......Start channel; 0 -> 1
ECHAN......End channel; 0 -> max
NCHAV......Number of channels to average. Note that ECHAN is
adjusted if necessary to make (ECHAN-BCHAN+1) and integer
multiple of NCHAV. 0 -> 1.
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).
BADDISK....The disk numbers to avoid for scratch files (sorting
tables mostly).
EXPLAIN SECTION