AIPS HELP file for IBLED in 31DEC21
As of Sun May 16 18:21:28 2021
IBLED: Task to edit data baseline-by-baseline using the TV
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 #
DOCAT -1.0 2.0 Catalog work file ?
IN2SEQ 0.0 Sequence number of work file
IN2DISK 0.0 9.0 Disk on which to write work
file, 0 => any
DOHIST -3.0 1.0 Record flags in history file
SOURCES Source list
CALCODE Calibrator code ' '=>all
Source model to plot:
IN3NAME CLEAN map name (name)
IN3CLASS CLEAN map name (class)
IN3SEQ 0.0 9999.0 CLEAN map name (seq. #)
IN3DISK 0.0 9.0 CLEAN map disk unit #
IN3VER -1.0 46655.0 CC file version #
NMAPS 0.0 4096.0 No. CLEAN map files
NCOMP # comps to use for model.
1 value per field
FLUX Lowest CC component used.
TIMERANG Time range to include
STOKES Stokes type to display
SELBAND Bandwidth to select (kHz)
SELFREQ Frequency to select (MHz)
FREQID Freq. ID to select.
BIF 0.0 1000.0 Lowest IF number 0=1
EIF 0.0 1000.0 Highest IF number
BCHAN 0.0 8192.0 Lowest channel number 0=>1
ECHAN 0.0 8192.0 Highest channel number
ANTENNAS Antennas to edit.
BASELINE Baselines with ANTENNAS
UVRANGE 0.0 UV range in kilolambda
SUBARRAY 0.0 1000.0 Subarray, 0 => all
Cal. info for input:
DOCALIB -1.0 101.0 > 0 calibrate data & weights
> 99 do NOT calibrate weights
GAINUSE CAL (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 0 => high
< 0 no flagging on input
Used w single-source too
OUTFGVER 0.0 Output FG 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
HELP SMOOTH for details.
Task enrichment parameters:
DPARM (1) 0 => display amplitude
1 => display phase,
can change interactively
(2) if > 0, include
(3) if > 0 will average IFs
selected with BIF to EIF
(4) input data interval in
secs. <=0 -> 10
PLEASE SET 4 & 5 !
(5) data averaging time in
secs: <=0 => >= 10
(6) If > 1, plot error bars,
can change interactively
(7) Min value to plot, can
be changed interactively.
0 => use min. in data
(8) Max value to plot, can
be changed interactively.
0 => use max. in data
(9) If > 1, don't plot whole
visibility function along
the top of the screen,
can change interactively
BADDISK Disks to avoid for master and
Use: To edit visibility data interactively. This task is complementary
to TVFLG and will be mainly useful for editing data from
interferometers with a relatively small number of baselines (e.g.
VLBI experiments). The visibility function for a single baseline
is displayed on the TV device and the user has various editing
options (all under a menu-like control interface) available to
flag bad data. There are also various display and data selection
options available in the menu. For multi-source data a flagging
(FG) table is written;, for single-source data the flagging
information is applied at the end of the editing sessions.
IBLED is for editing continuum data from one or more IFs.
Multiple spectral channels may be averaged in the master file
used for display and editing, while multiple IFs may be averaged
together or kept separate. These averagings as well as an option
time averaging may be used to find the ratio of the vector- to
scalar-averaged amplitudes. This will be 1.0 for stable data of
high signal-to-noise and near 0 for signal-free data. This ratio
may be displayed and used in editing in addition to the displays
and uses of the vector-averaged amplitude and phase. If the IFs
are kept separate, one may also display and edit the ratio in
amplitude or difference in phase of one IF to a second.
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.
DOCAT......True (>0) means to use a cataloged file for the "master
file". It creates a new one or uses an old one, depending
on the value of IN2SEQ. One can run IBLED a number of
times using the same master file, before applying the final
list of flag commands to the input data file. (The master
file is destroyed when the flag commands are applied or, if
DOCAT <= 0, on EXIT.) If DOCAT = 2 and IN2SEQ = 0, then
the program returns to the user immediately, prepares the
cataloged master file, and then exits. The program must be
rerun with an appropriate, non-zero value of IN2SEQ to flag
the data. This option allows the user to do other things
while creating a large master grid file.
IN2SEQ.....Sequence number of cataloged master grid file. 0 => create
new one, else use existing one of seq number = IN2SEQ.
NOTE: to use this option, all of the adverbs must have the
same value as when the old grid file was created.
IN2DISK....Disk on which to write the catalogued work file,
0 => choose a disk, avoiding those in BADDISK.
DOHIST.....> 0 => record task execution and flagging info in the
history file (this can be a lot!). <= 0.0 means to omit
the flagging info and <= -9.5 means to omit the execution
information as well.
SOURCES....List of sources to be displayed. ' '=> all; if any starts
with a '-' then all except ANY source named.
CALCODE....Sources may be selected on the basis of calibrator code:
' ' => any calibrator code selected
'* ' => any non blank code (cal. only)
'-CAL' => blank codes only (no calibrators)
anything else = calibrator code to select.
IN3NAME....Source model file name. If selected, a plot of the model
amplitude will appear as an overlay in the lower frame.
This can be selected or de-selected using the "PLOT MODEL"
option on the left-hand menu. The model will not be plotted
for phase or de-correlation data. Models made with either
value of DO3DIMAG in IMAGR are supported.
IN3CLASS...Source model file class
IN3SEQ.....Source model file sequence number
IN3DISK....Source model disk number
IN3VER.....CC file version # for source model file
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.
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.
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
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.......Only components > FLUX in absolute value are used in the
TIMERANG...Time range of the data to be displayed. In order: Start
day, hour, min., sec, end day, hour, min., sec. in days
relative to reference date.
STOKES.....The desired Stokes type of the data for display and
editing. It is probably a good idea to view the data
without Stokes conversion, i.e., STOKES = ' '. However,
there may be times when conversion to, say, STOKES = 'IQUV'
may make sense. Note that a flag of Stokes I flags both RR
and LL. The value of STOKES controls the default set of
polarizations (correlators) to be flagged. However, you
may enter interactively any desired and reasonable set.
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 result in an ambiguity. In that case, the task
will request that you use FREQID.
BIF........Lowest IF to grid. Note that unless you have requested the
selected IF's to be averaged together (see DPARM(3)) then
the first IF displayed on the TV will be BIF, other IF's
can then be displayed interactively by selecting them from
NOTE to VLA users: IF=1 corresponds to the VLA AC ifpairs
and IF=2 corresponds to the BD ifpairs.
EIF........Highest IF to grid. 0 => highest.
BCHAN......First channel to AVERAGE together. 0 => 1.
ECHAN......Last channel to AVERAGE. 0 => highest.
ANTENNAS...A list of the antennas to edit. If any number is negative
then all antennas listed are NOT desired and all others
are. All 0 => edit all.
BASELINE...Baselines to be edited, use BASELINE and ANTENNAS. Eg.
baselines 1-6,1-8, 2-6 and 2-8 use ANTENNAS=1,2;
UVRANGE....Range of projected spacings to be gridded in 1000's of
wavelengths. 0 => 1, 1.E10
SUBARRAY...Subarray number to grid. 0 => all. If you have
multi-source data with more than one source at a time, then
you will need to specify the SUBARRAY and do one of them at
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 Cal. table to apply to the data if
DOCALIB=1. Refers to a CL table for multi-source data or
an SN table for single-source. 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 for reading the data. FLAGVER = -n => no
flagging on input.
OUTFGVER...Flag table version to be used on output for both single-
and multi-source data sets. If OUTFGVER is <= 0 or
greater than FGmax (the previously highest FG version
number), then a new FG table will be created for the new
flags with version FGmax+1. This new table will also
contain the flags applied on input (if any) from FG
version FLAGVER. If OUTFGVER specifies a pre-existing FG
version, then the input flags are not copied even if
OUTFGVER and FLAGVER are not equal.
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
(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
BPVER......(multi-source) 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
DPARM......(1) = 0 => display amplitudes for editing
= 1 => display phases for editing
These can be interactively toggled within the task.
(2) if > 0, autocorrelation data will be calibrated and
averaged into the master file
(3) if > 0 will average IFs BIF through EIF.
(4) Normal integration time found in the data. PLEASE
PROVIDE THIS NUMBER. 0 => 10 seconds to the routine
that reads in the data averaging and calibrating them.
Then a new integration time will be used based on the
averaged data of the first baseline.
(5) Data samples within DPARM(5) seconds are averaged after
calibration. This averaging along with averaging over
IFs and/or spectral channels provides the estimate of
the decorrelation. IT IS BEST TO SET THIS VALUE.
If DPARM(5) <= 0, the task will average the data to 10
seconds and then read through the averaged data of the
first baseline and set the sampling to the minimum
interval found (>= 10 seconds).
(6) if > 1 then IBLED will assume that the weights
associated with the data are correctly scaled so as to
be easily related to true error bars and will plot them
as such. The default is not to plot error bars and to
represent each datum with the same size vector on the
TV. This can be changed interactively.
(7) Minimum amplitude (Jy) (or phase (degrees)) to be
(8) Maximum amplitude (Jy) (or phase (degrees)) to be
displayed. Both DPARM(6) and (7) can be set
(9) If = 0 => plot the whole of the visibility function for
the particular baseline across the top of the TV.
Normally a baseline will have more data points than
there are pixels across the TV so IBLED will only plot
part of the data in the main editing frame, however it
is useful to be able to see the whole visibility
function while only editing part of it, this option
enables the user to do that. If DPARM(9) = 1 then the
whole visibility function will not be plotted. This can
be changed interactively.
BADDISK....List of disks to avoid for BOTH scratch files and the
master file (if OUTDISK = 0).
IBLED has three main steps:
(1) The data are selected and calibrated using all of the usual
calibration adverbs and options. Then they are averaged over
spectral channels BCHAN through ECHAN, over IFs BIF through EIF (if
DPARM(3) > 0), and over DPARM(5) seconds of time. The resultant
visibilities are written to a "master file" which is cataloged
temporarily or (semi) permanently on disk INDISK2 with class IBLEDR.
Each visibility record in this file consists of a weight,
vector-averaged amplitude, vector-averaged phase, and
"decorrelation" index (ratio of vector-averaged to scalar-averaged
amplitude). For autocorrelation data, the amplitude is the real
part (with sign) and the decorrelation is the rms in the real part.
This master file can be used in one or, if DOCAT > 0, more than one
session of step (2) below to prepare flag commands which are stored
in an FC table attached to the master file.
(2) The session(s) in which the user interacts with his data arranging
the TV display and then selecting which data are to be flagged. The
data are plotted with time along the X axis plotting one point per
TV pixel and skipping 20 pixels between scans. Therefore, the time
axis is quite non-linear. Tick marks are placed at integer hour
points along the X axis and the end points labeled to provide you
with some idea of the times. All interactive editing operations
provide detailed displays of the currently selected time and
visibility. The main editing area may not be large enough to
contain all the data. In this case, a smaller "frame" of data is
selected and you may alter the selected frame to gain access to all
of your data. A small plot at the top of the screen shows all of
the data, potentially with a fairly crowded X (time) axis.
(3) The actual flagging of the data and writing of the history file. A
flag table is written for multi-source files and the uv data
themselves are flagged for single-source files. This should be done
when exiting if you have not cataloged the master file (i.e. DOCAT
<= 0) or when you are fully satisfied with your flag commands. When
the flags are applied to the input data set, the master file is
The interactive session is driven by a menu which is displayed on the
same screen as the data. Move the cursor to the desired operation
(noting that the currently selected one is highlighted in a different
color on many TVs) and press button A, B, or C to select the operation.
Press button D for a short explanation of the selected operation. The
first column contains options to alter the display of the data and the
choice of which data are flagged ultimately. The second column has 7
interactive modes for selecting data to be flagged, 2 operations on the
FC table itself, and 10 operations which cause the display to be
When the menu is displayed, one or more lines of status information are
displayed at the bottom of the screen. The line that is always present
shows the type of data displayed and which Stokes and whether one or all
sources, IFs, and channels will be flagged by the next flag commands.
If all baselines to on or both of the displayed antennas will be flagged
and/or if the points are currently plotted with error bars, a second
line reflecting this fact will be displayed. If the Stokes type, the
first or second IF, or the error bar type will change on the next LOAD,
then another line is displayed saying "NEXT LOAD SHOWS" these new
things. Finally, if some data are omitted from the plot due to
user-selected plot scaling, then another line appears warning of this
fact. The plot of the data is labeled along the vertical axis by normal
labeled tick marks and the units, while the horizontal axis has ticks at
integer hours and time strings at both ends of the plotted data. The
line at the top of the plot identifies the data currently displayed.
The left-hand menu section begins with 3 operations to alter the TV
display zoom and color transfer functions. The zoom is useful for
greater accuracy in selecting data to be flagged. Then there are 3
options to set the range of amplitude, phase, and decorrelations which
are actually plotted. These default to the full range in the current
data, and can be set back to default by entering 0 0. The next two
options ask you to enter the desired IF number and Stokes type for the
next display, but do not actually change the display. Use any of the
redisplay options in the second menu (LOAD is simplest) to update the
display. The next option allows you to specify a second IF number.
When that is not 0 and not the same as the first IF, IBLED plots the
amplitude ratio or phase difference of the first IF and the second IF.
The next 5 options switch the binary states of several flags: the first
controls the plotting of the full data set in the small plot at the top,
the second controls the vertical bars plotted about the data switching
betwen error estimates and a small constant, and the rest control
whether one or all spectral channels, IFs, and sources are flagged by
the following flag commands. The next option allows you to set the
Stokes which will be flagged by the following flag commands (see below).
And the final 2 options allow you to switch between flagging only the
displayed baseline and flagging all antennas to one or both of those
displayed. The last two menu items actually reflect the station names
for the two antennas and change as you change baselines.
The menu looks like:
| OFF ZOOM | To turn off any zoom magnification
| OFF ENHANCEMENT | To turn of black & white and pseudo-color
enhancements (usually top plot only)
| TVFIDDLE | To do interactive zoom, pseudo-color contours, or
black and white enhancement
| ENTER AMP RANGE | To type in the intensity range to be used for
plotting amplitudes (Jy or ratio)
| ENTER PHS RANGE | To type in the phase range to be used for plotting
| ENTER DCR RANGE | To type in the decorrelation range to be used to
plot decorrelation (0-1 or ratio)
| ENTER IF | To enter on the terminal the desired IF to be
| ENTER STOKES | To enter on the terminal the STOKES type to be
| RATIO 2ND IF | To enter on the terminal the IF to divide into the
first IF to display ratios of data . 0 turns off
| SHOW TOP PLOT | To toggle switch to display complete data for
current baseline along top of screen
| PLOT MODEL | To toggle between displaying and not displaying
the model visibility (when selected by adverbs)
| PLOT ERROR BARS | To toggle switch to plot error bars or a small
constant bar - works only with fully calibrated
| SWTCH 1-CH FLAG | To toggle between flagging all spectral channels
and only BCHAN-ECHAN.
| SWTCH 1-IF FLAG | To toggle between flagging all IFs or only the one
shown (or BIF-EIF if averaged).
| SWTCH 1-SO FLAG | To toggle between flagging all sources in any time
range and only those displayed.
| SET STOKES FLAG | To enter on the terminal the 4-character string
which will control which correlators
(polarizations) are flagged. Note: this parameter
applies only to flag commands prepared after it is
set. It should be changed whenever a different
Stokes is displayed. See also below.
| FLAG station1 | To toggle switch between flagging all data to this
antenna and only station2.
| FLAG station2 | To toggle switch between flagging all data to this
antenna and only station1.
The all-channel flag remains true if the full range of channels in the
input data set are averaged in the data being flagged. The all-IF flag
remains true if the full range of IFs in the input data set are averaged
in the data being flagged.
The right-hand menu section begins with 8 flagging operations: to flag
one time at a time, to flag a range of times, to flag an area in the
intensity-time plane, to flag all points above some intensity or below
some intensity, to flag all points more than x times the rms from the
mean, to flag all points above or below a user-drawn curve in the
intensity-time plane, and lastly, to flag all times in all frames for
the displayed data. During the first 7 operations the current position
selected by the cursor is displayed in the upper left hand corner of the
TV with source name, time, flux, and (optionally) error. Lines or boxes
are also drawn in the TV to indicate the area being selected for
flagging. During interactive flagging, button A switches between
corners or end times except for FLAG TIME where it does the flagging and
FLAG INTERACTIV where it marks a point. Button B does the flagging and
loops for more except for FLAG INTERACTIV where it marks another point
on the curve. Button C also does the flagging, but the program then
returns to the main menu rather than prompting for more flagging
selections. Button D exits back to the menu without doing any
additional flagging. When a flagging command is generated, any flagged
data currently displayed are erased (only from the lower plot) and some
number of records are written into the FC table. Note that one can flag
only those data in the current frame using the intensity type in the
current display (plus other IFs, Stokes, etc. as chosen by the flagging
control commands). You must visit other frames in order to flag them.
The last flag operation, FLAG ALL TIME, is not interactive and simply
flags all data for the displayed baseline (or antenna) for all times
in all frames.
The next two operations in the right-hand menu allow you to list the
flag commands already in the FC table and to undo any of them. The UNDO
FLAGS peration prompts you for a list of flags to be undone by number
(get these from LIST FLAGS) with 0 ending the list. When a flag is
undone, all cells in the master file which were first flagged by that
command are restored to use, except for those also flagged by some later
command. This is done automatically by IBLED without the special
commands required by TVFLG. After an UNDO FLAGS operation, the TV is
reloaded, potentially with new plot scales.
The next 10 operations in the right-hand menu also cause the display to
be updated immediately if needed. The first three select the type of
data to be displayed and used in flagging; the next four change the
current frame (portion of the current baseline) being displayed and
edited; the next two change the current baseline, and the last forces an
update of the screen including the top plot in case some of the changes
(e.g. flagged points, new IF or Stokes selection, etc.) have not been
fully reflected in the displays. The SELECT FRAME uses the top plot to
select the desired frame interactively and can work only when the top
plot is displayed. The last option in this menu selection is to EXIT,
optionally applying an flagging commands to the input data set.
The menu looks like:
| FLAG TIME | To flag single visibility points
| FLAG TIME RANGE | To flag all data in a range of times
| FLAG AREA | To flag a rectangular area in the flux-time plane
| FLAG ABOVE | To set a lower limit and flag all data above over
a selected range of times
| FLAG BELOW | To set an upper limit and flag all data below over
a selected range of times
| FLAG ABOUT MEAN | To set a time range within which the mean and rms
are determined and then flag all data outside the
range MEAN +/- x * RMS, where the user is asked to
specify x and to confirm the flagging.
| FLAG INTERACTIV | To define a piecewise-linear curve and then flag
all data above or below it
| FLAG ALL TIME | To flag all times in all frames at once
| LIST FLAGS | To list selected range of flag commands
| UNDO FLAGS | To remove flags by number from FC table and undo
that flagging in the data
| SHOW AMPLITUDE | To reload the TV displaying amplitudes
| SHOW PHASE | To reload the TV displaying phases
| SHOW DECORRELAT | To reload the TV displaying decorrelation index
| SELECT FRAME | To select the visibility set to be displayed
interactively from the top plot
| FIRST FRAME | To display the first set of visibilities
| NEXT FRAME | To display the next set of visibilities
| PREVIOUS FRAME | To display the previous set of visibities
| SELECT BASELINE | To display a new baseline by entering the desired
antenna pair on the terminal
| NEXT BASELINE | To display the first set of visibilties from the
| PREV BASELINE | To display the first set of visibilties from the
| LOAD | To reload the TV with the current flags and
parameters, checking the scale
| EXIT | To resume AIPS and, optionally, enter the flags in
Before the flags are entered in the data, IBLED asks the user whether or
not he actually wishes to do this. You must respond yes or no. If the
master file is not cataloged (DOCAT <= 0), then your flags will be lost
if you do not say yes. If the master file is cataloged and you intend
to do more flagging on this particualr set of data, then you should
answer no. Then, you can resume later without having to compute a new
master file and will have the option to undo previous IBLED flag
commands. Once the flags are applied to the input data set, they are
much harder to undo and the master file is destroyed since it no longer
accurately represents the input data.
The subject of Stokes flags deserves more discussion. In their simplest
form, they are a string of four 1's and 0's with the 1's represeenting
the correlators to be flagged and the 0's those that are not altered.
These strings always represent correlators in their basic groupings and
orders - I/Q/U/V or RR/LL/RL/LR or XX/YY/XY/YX - even if the current
data set only has, say, LL data. IBLED allows you to enter Stokes flags
in this form, but also allows more mnemonic forms as well. If I, Q, U,
and/or V data are displayed, then the strings i, Q, U, V, IQU, IQUV, and
IV are also accepted. If RR, LL, RL, and/or LR data are displayed, then
the strings RR, LL, RL, LR, HALF, NOLL, NORR, RRLL, and RLLR are
accepted (HALF = RRLL = 1100, NOLL = 1011, NORR = 0111). If XX, YY, XY,
and/or YX data are displayed, then the strings XX, YY, XY, YX, HALF,
NOYY, NOXX, XXYY, and XYYX are accepted (HALF = XXYY = 1100, NOYY =
1011, NOXX = 0111). FULL is always accepted as 1111. Inside IBLED,
these strings apply to the Stokes form(s) chosen for editing and
display, which, because of the STOKES input adverb, are not necessarily
those of the input data set. If they are of different forms then a
translation must take place. The only such translation that is likely
to occur is when the user edits in I/Q/U/V a data set in RR/LL/RL/LR.
In this case, any flag of I and/or V flags both RR and LL and any flag
of Q and/or U flags both RL and LR. IBLED attempts to support the other
translations as well.