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NRAO Home > CASA > CASA Cookbook and User Reference Manual |
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8.2.1.1 sdcal
infile -- name of input SD dataset
antenna -- antenna name or id (only effective for MS input).
fluxunit -- units for line flux
options: ’K’,’Jy’,’’
default: ’’ (keep current fluxunit)
WARNING: For GBT data, see description below.
>>> fluxunit expandable parameter
telescopeparm -- the telescope characteristics
options: (str) name or (list) list of gain info
default: ’’ (none set)
example: if telescopeparm=’’, it tries to get the telescope
name from the data.
Full antenna parameters (diameter,ap.eff.) known
to ASAP are
’ATPKSMB’, ’ATPKSHOH’, ’ATMOPRA’, ’DSS-43’,
’CEDUNA’,’HOBART’. For GBT, it fixes default fluxunit
to ’K’ first then convert to a new fluxunit.
telescopeparm=[104.9,0.43] diameter(m), ap.eff.
telescopeparm=[0.743] gain in Jy/K
telescopeparm=’FIX’ to change default fluxunit
see description below
specunit -- units for spectral axis
options: (str) ’channel’,’km/s’,’GHz’,’MHz’,’kHz’,’Hz’
default: ’’ (=current)
example: this will be the units for masklist
frame -- frequency frame for spectral axis
options: (str) ’LSRK’,’REST’,’TOPO’,’LSRD’,’BARY’,
’GEO’,’GALACTO’,’LGROUP’,’CMB’
default: currently set frame in scantable
WARNING: frame=’REST’ not yet implemented
doppler -- doppler mode
options: (str) ’RADIO’,’OPTICAL’,’Z’,’BETA’,’GAMMA’
default: currently set doppler in scantable
calmode -- calibration mode
options: ’ps’,’nod’,’fs’,’fsotf’,’quotient’,’none’
default: ’none’
example: choose mode ’none’ if you have
already calibrated and want to
try averaging
WARNING: ’fsotf’ is not implemented yet
scanlist -- list of scan numbers to process
default: [] (use all scans)
example: [21,22,23,24]
this selection is in addition to field, iflist, and pollist
field -- selection string for selecting scans by name
default: ’’ (no name selection)
example: ’FLS3a*’
this selection is in addition to scanlist, iflist, and pollist
iflist -- list of IF id numbers to select
default: [] (use all IFs)
example: [15]
this selection is in addition to scanlist, field, and pollist
pollist -- list of polarization id numbers to select
default: [] (use all polarizations)
example: [1]
this selection is in addition to scanlist, field, and iflist
channelrange -- channel range selection
default: [] (use all channel)
example: [0,5000]
Note that specified values are recognized as ’channel’
regardless of the value of specunit
scanaverage -- average integrations within scans
options: (bool) True,False
default: False
timeaverage -- average times for multiple scan cycles
options: (bool) True,False
default: False
example: if True, this happens after calibration
>>>timeaverage expandable parameter
tweight -- weighting for time average
options: ’none’
’var’ (1/var(spec) weighted)
’tsys’ (1/Tsys**2 weighted)
’tint’ (integration time weighted)
’tintsys’ (Tint/Tsys**2)
’median’ ( median averaging)
default: ’none’
averageall -- average multi-resolution spectra
spectra are averaged by referring
their frequency coverage
default: False
polaverage -- average polarizations
options: (bool) True,False
default: False
>>>polaverage expandable parameter
pweight -- weighting for polarization average
options: ’none’
’var’ (1/var(spec) weighted)
’tsys’ (1/Tsys**2 weighted)
default: ’none’
tau -- atmospheric optical depth
default: 0.0 (no correction)
verify -- verify the results of calibration. Only effective if
calmode is not ’none’.
options: (bool) True,False
default: False
WARNING: Currently this just asks whether you accept
the displayed calibration and if not, continues
without doing any calibration.
outfile -- Name of output file
default: ’’ (<infile>_cal)
outform -- format of output file
options: ’ASCII’,’SDFITS’,’MS’,’ASAP’
default: ’ASAP’
example: the ASAP format is easiest for further sd
processing; use MS for CASA imaging.
If ASCII, then will append some stuff to
the outfile name
overwrite -- overwrite the output file if already exists
options: (bool) True,False
default: False
WARNING: if outform=’ASCII’, this parameter is ignored
plotlevel -- control for plotting of results
options: (int) 0=none, 1=some, 2=more, <0=hardcopy
default: 0 (no plotting)
example: plotlevel<0 as abs(plotlevel), e.g.
-1 => hardcopy of final plot (will be named
<outfile>_calspec.eps)
WARNING: be careful plotting in fsotf mode!
DESCRIPTION:
Task sdcal performs data selection, calibration for single-dish spectra. By setting calmode=’none’, one can run sdcal on already calibrated data, for further selection , averaging and atmospheric optical depth correction. To save the output spectra in a certain range of channels, you set the range in channelrange.
If you give multiple IFs in iflist, then your scantable will have multiple IFs by default. Averaging of multi-resolution (multi-IFs) spectra can be achieved by setting a sub-parameter in timeaverage, averageall, to True. It handles multi-IFs by selecting overlaps in frequency coverages and assigning new IFs in the output spectra.
ASAP recognizes the data of the ”AT” telescopes, but currently does not know about the GBT or any other telescope. This task does know about GBT. Telescope name is obtained from the data. If you wish to change the fluxunit (see below), by leaving the sub-parameter telescopeparm unset (telescopeparm=’’), it will use internal telescope parameters for flux conversion for the data from AT telescopes and it will use an approximate aperture efficiency conversion for the GBT data. If you give telescopeparm a list, then if the list has a single float it is assumed to be the gain in Jy/K, if two or more elements they are assumed to be telescope diameter (m) and aperture efficiency respectively.
Note that sdcal assumes that the fluxunit is set correctly in the data already. If not, then set telescopeparm=’FIX’ and it will set the default units to fluxunit without conversion. NOTE: If the data in infile is an ms from GBT and the default flux unit is missing, this task automatically fixes the default fluxunit to ’K’ before the conversion.
WARNING for the GBT raw SDFITS format data as input:
SDtasks are able to handle GBT raw SDFITS format (version 1.3) data since the data filler is
available. However, the functionality is not well tested yet, so that there may be unknown
bugs.
Notes:
- Direction information is not considered when data is averaged. Use sdgrid task if you want to take care of direction information when averaging.
- Calibration of frequency switching data is now fully implemented, including folding.
- Additional calibration algorithms are implemented. These are the ’Chopper-Wheel’ calibration and the one adopted in APEX telescope (an advanced version of classical ’Chopper-Wheel’ method). Two load calibration, which will be a standard calibration mode of ALMA total power antennas, is formally implemented but still experimental.
R3.4 New Features:
This task has been renamed, and was previously called sdaverage.
More information about CASA may be found at the
CASA web page
Copyright © 2010 Associated Universities Inc., Washington, D.C.
This code is available under the terms of the GNU General Public Lincense
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