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casa
$Rev:20696$
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casa
$Rev:20696$
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Functions | |
| def | bandpass |
| def bandpass.bandpass | ( | vis = '', |
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caltable = '', |
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field = '', |
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spw = '', |
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intent = '', |
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selectdata = True, |
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timerange = '', |
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uvrange = '', |
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antenna = '', |
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scan = '', |
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observation = '', |
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msselect = '', |
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solint = 'inf', |
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combine = 'scan', |
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refant = '', |
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minblperant = 4, |
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minsnr = 3.0, |
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solnorm = False, |
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bandtype = 'B', |
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smodel = [], |
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append = False, |
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fillgaps = 0, |
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degamp = 3, |
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degphase = 3, |
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visnorm = False, |
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maskcenter = 0, |
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maskedge = 5, |
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gaintable = [''], |
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gainfield = [''], |
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interp = [''], |
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spwmap = [], |
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gaincurve = False, |
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opacity = [], |
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parang = False |
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| ) |
Calculates a bandpass calibration solution
Determines the amplitude and phase as a function of frequency for
each spectral window containing more than one channel. Strong sources
(or many observations of moderately strong sources) are needed to obtain
accurate bandpass functions. The two solution choices are: Individual
antenna/based channel solutions 'B'; and a polynomial fit over the channels
'BPOLY'. The 'B' solutions can determined at any specified time interval, and
is recommended if each channel has good signal-to-noise. Other, 'BPOLY' is
recommended.
Keyword arguments:
vis -- Name of input visibility file
default: none; example: vis='ngc5921.ms'
caltable -- Name of output bandpass calibration table
default: none; example: caltable='ngc5921.bcal'
--- Data Selection (see help par.selectdata for more detailed information)
field -- Select field using field id(s) or field name(s).
[run listobs to obtain the list id's or names]
default: ''=all fields
If field string is a non-negative integer, it is assumed a field index
otherwise, it is assumed a field name
field='0~2'; field ids 0,1,2
field='0,4,5~7'; field ids 0,4,5,6,7
field='3C286,3C295'; field named 3C286 adn 3C295
field = '3,4C*'; field id 3, all names starting with 4C
spw -- Select spectral window/channels
default: ''=all spectral windows and channels
spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
spw='<2'; spectral windows less than 2 (i.e. 0,1)
spw='0:5~61'; spw 0, channels 5 to 61
spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, channels 3 to 45.
spw='0~2:2:6'; spw 0,1,2 with channels 2 through 6 in each.
spw='0:0~10;15~60'; spectral window 0 with channels 0-10,15-60
NOTE: ';' to separate channel selections
spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10,
spw 1, channels 20-30, and spw 2, channels, 1,2 and 3
intent -- Select observing intent
default: '' (no selection by intent)
intent='*BANDPASS*' (selects data labelled with
BANDPASS intent)
selectdata -- Other data selection parameters
default: True
timerange -- Select data based on time range:
default = '' (all); examples,
timerange = 'YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss'
Note: if YYYY/MM/DD is missing dat defaults to first day in data set
timerange='09:14:0~09:54:0' picks 40 min on first day
timerange= '25:00:00~27:30:00' picks 1 hr to 3 hr 30min on next day
timerange='09:44:00' data within one integration of time
timerange='>10:24:00' data after this time
uvrange -- Select data within uvrange (default meters)
default: '' (all); example:
uvrange='0~1000kl'; uvrange from 0-1000 kilo-lamgda
uvrange='>4kl';uvranges greater than 4 kilo-lambda
antenna -- Select data based on antenna/baseline
default: '' (all)
If antenna string is a non-negative integer, it is assumed an antenna index
otherwise, it is assumed as an antenna name
antenna='5&6'; baseline between antenna index 5 and index 6.
antenna='VA05&VA06'; baseline between VLA antenna 5 and 6.
antenna='5&6;7&8'; baseline 5-6 and 7-8
antenna='5'; all baselines with antenna 5
antenna='5,6,10'; all baselines with antennas 5, 6 and 10
scan -- Select data based on scan number - New, under developement
default: '' (all); example: scan='>3'
observation -- Observation ID(s).
default: '' = all
example: '0~2,4'
msselect -- Optional complex data selection (ignore for now)
--- Solution parameters
solint -- Solution interval in time (units optional), and (optionally)
in frequency. Frequency pre-averaging can be
specified after a comma in units of channels or Hz.
If nothing is specified for frequency, no freq pre-averaging
will be done.
default: 'inf' (~infinite, up to boundaries controlled by combine,
with no pre-averaging in frequency)
Options for time: 'inf' (~infinite), 'int' (per integration), any float
or integer value with or without units
Options for freq: an integer with 'ch' suffix will enforce
pre-averaging by the specified number
of channels.
a numeric value suffixed with frequency
units (e.g., 'Hz','kHz','MHz') will enforce
pre-averaging by an integral number of
channels amounting to no more than the
specified bandwidth
examples: solint='1min'; solint='60s', solint=60 --> 1 minute
solint='0s'; solint=0; solint='int' --> per integration
solint='-1s'; solint='inf' --> ~infinite, up to boundaries
enforced by combine
solint='inf,8Mhz' --> ~infinite in time, with
8MHz pre-average in freq
solint='int,32ch' --> per-integration in time,
with 32-channel pre-average
in freq
combine -- Data axes to combine for solving
default: 'scan' --> solutions will break at field and spw boundaries,
but may extend over multiple scans (per field and spw) up
to solint.
Options: '','scan','spw',field', or any comma-separated combination
example: combine='scan,spw' --> extend solutions over scan boundaries
(up to the solint), and combine spws for solving
refant -- Reference antenna name(s); a prioritized list may be specified
default: '' (no reference antenna)
example: refant='13' (antenna with index 13)
refant='VA04' (VLA antenna #4)
refant='EA02,EA23,EA13' (EVLA antenna EA02, use
EA23 and EA13 as alternates if/when EA02
drops out)
Use 'go listobs' for antenna listing
minblperant -- Minimum number of baselines required per antenna for each solve
Antennas with fewer baaselines are excluded from solutions. Amplitude
solutions with fewer than 4 baselines, and phase solutions with fewer
than 3 baselines are only trivially constrained, and are no better
than baseline-based solutions.
default: 4
example: minblperant=10 => Antennas participating on 10 or more
baselines are included in the solve
minsnr -- Reject solutions below this SNR (only applies for bandtype = B)
default: 3.0
solnorm -- Normalize bandpass amplitudes and phase for each
spw, pol, ant, and timestamp
default: False (no normalization)
bandtype -- Type of bandpass solution (B or BPOLY)
default: 'B'; example: bandtype='BPOLY'
'B' does a channel by channel solution for each
specified spw.
'BPOLY' is somewhat experimental. It will fit an
nth order polynomial for the amplitude and phase
as a function of frequency. Only one fit is made
for all specified spw, and edge channels should be
omitted.
Use taskname=plotcal in order to compare the results from
B and BPOLY.
fillgaps -- Fill flagged solution channels by interpolation
default: 0 (don't interpolate)
example: fillgaps=3 (interpolate gaps 3 channels wide and narrower)
degamp -- Polynomial degree for BPOLY amplitude solution
default: 3; example: degamp=2
degphase -- Polynomial degree for BPOLY phase solution
default: 3; example: degphase=2
visnorm -- Normalize data prior to BPOLY solution
default: False; example: visnorm=True
maskcenter -- Number of channels to avoid in center of each band
default: 0; example: maskcenter=5 (BPOLY only)
maskedge -- Fraction of channels to avoid at each band edge (in %)
default: 5; example: maskedge=3 (BPOLY only)
append -- Append solutions to the (existing) table
default: False; example: append=True
--- Other calibrations to apply on the fly before determining bandpass solution
gaintable -- Gain calibration table(s) to apply
default: '' (none);
examples: gaintable='ngc5921.gcal'
gaintable=['ngc5921.ampcal','ngc5921.phcal']
gainfield -- Select a subset of calibrators from gaintable(s)
default:'' ==> all sources in table;
'nearest' ==> nearest (on sky) available field in table
otherwise, same syntax as field
example: gainfield='0~3'
gainfield=['0~3','4~6']
interp -- Interpolation type (in time[,freq]) to use for each gaintable.
When frequency interpolation is relevant (B, Df, Xf),
separate time-dependent and freq-dependent interp
types with a comma (freq _after_ the comma).
Specifications for frequency are ignored when the
calibration table has no channel-dependence.
Time-dependent interp options ending in 'PD' enable a
"phase delay" correction per spw for non-channel-dependent
calibration types.
default: '' --> 'linear,linear' for all gaintable(s)
example: interp='nearest' (in time, freq-dep will be
linear, if relevant)
interp='linear,cubic' (linear in time, cubic
in freq)
interp=',spline' (spline in freq; linear in
time by default)
interp=['nearest,spline','linear'] (for multiple gaintables)
Options: Time: 'nearest', 'linear'
Freq: 'nearest', 'linear', 'cubic', 'spline'
spwmap -- Spectral windows combinations to form for gaintable(s)
default: [] (apply solutions from each spw to that spw only)
Example: spwmap=[0,0,1,1] means apply the caltable solutions
from spw = 0 to the spw 0,1 and spw 1 to spw 2,3.
spwmap=[[0,0,1,1],[0,1,0,1]]
gaincurve -- Apply internal VLA antenna gain curve correction (True/False)
default: False;
Use gaincurve=True ONLY for VLA data
opacity -- Opacity correction to apply (nepers), per spw
default: [] (no opacity correction for any spw)
examples:
A global value for all spws:
opacity=0.051
Different values for spws 0,1,2:
opacity=[0.051, 0.055, 0.057]
(if more than 3 spws, spw 3 and higher will
be assigned the last specified value, or 0.057)
Typical VLA values are: 5 GHz - 0.013, 8 GHz - 0.013
15 GHz - 0.016, 23 GHz - 0.051, 43 GHz - 0.07
parang -- If True, apply the parallactic angle correction (required
for polarization calibration)
default: FalseDefinition at line 13 of file bandpass.py.
References task_bandpass.bandpass(), and vla_uvfits_line_sf.verify.
1.8.0