AIPS NRAO AIPS HELP file for SPCAL in 31DEC18



As of Fri Oct 19 17:55:10 2018


SPCAL: Task to compute instrumental polzn. for spec. line data

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 #
                                   Data selection (multisource):
CALSOUR                            Sources to calibrate with
TIMERANG                           Time range to use.
SELBAND                            Bandwidth to select (kHz)
SELFREQ                            Frequency to select (MHz)
FREQID                             Freq. ID to select.
BIF               0.0      100.0   IF number.
ANTENNAS                           Antennas to solve for.
UVRANGE           0.0              UV range in kilolamdba
SUBARRAY          0.0     1000.0   Subarray, 0=>all
BCHAN             0.0     2048.0   Lowest channel number 0=>all
ECHAN             0.0     2048.0   Highest channel number 0=>all
                                   Cal. info for input:
DOCALIB          -1.0      101.0   > 0 calibrate data & weights
                                   > 99 do NOT calibrate weights
GAINUSE                            CAL table to apply.
BLVER                              BL table to apply.
FLAGVER                            Flag 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.
SOLINT                             Soln. interval (min) 0=>10.
SOLTYPE                            Soln. type:
                                    'ZAPR': zero. lin. pol.
                                    'RAPR': similarity method
PRTLEV            0.0       10.0   Print statistics 0=>none
                                   1 = some, 2 = lots. Use 1.
REFANT            0.0       90.0   Reference antenna, 0=none.
BADDISK           0.0        9.0   Disk no. not to use for
                                      scratch files.

HELP SECTION

SPCAL
Task:  This task reads a spectral line uv-data file,  applies
       calibration and determines the feed polarization parameters
       for each antenna for the selected IF. The instrumental
       polarization parameters are recorded in the AN table and can
       be applied in LISTR, SPLIT or other tasks by setting DOPOL>0.

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.

The following are used for multisource data files only:
  CALSOUR....List of sources for which calibration constants
             are to be determined.  '*' = all; a "-" before a
             source name means all except ANY source named.
             Note: solutions for multiple sources can only be
             made if the sources are point sources at their
             assumed phase center and with the flux densities
             given in the source (SU) table. All '  ' =>all.
  TIMERANG...Time range of the data to be used. In order:
             Start day, hour, min. sec,
             end day, hour, min. sec. Days relative to ref.
             date.
  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.
  BIF........First IF to process. Old values for feed parameters
             and calibrator polarizations for unprocessed IFs
             are unchanged.  0=>all.
  ANTENNAS...A list of the antennas to  have solutions
             determined. If any number is negative then all
             antennas listed  are NOT to be used to determine
             solutions and all others are. All 0 => use all.
The following may be used for all data files (except as noted):
  UVRANGE....Range of projected spacings to be included in
             1000's of wavelengths.  0  =>  1, 1.E10
  SUBARRAY...Subarray number to use. 0=>all.
  BCHAN......Lowest channel number included; 0 -> 1
  ECHAN......Highest channel number included; 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 or SN table to apply to
             the data.  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 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.
  BPVER......Specifies the version of the BP table to be applied.
             <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).
  SOLINT.....Time interval to average data before determining
             correction in min. 0 => 10 min.
  SOLTYPE....Solution type:
              'ZAPR': assumes zero linear polarization.
              'RAPR': assumes linear polarization is scaled
                      version of the total intensity.
              else -> ZAPR
  PRTLEV.....If this value is larger than 0.0 then the
             intermediate diagnostics and solutions will be
             given on the monitor terminal and the message file.
  REFANT.....Reference antenna to use.  If none is specified, the
             program will pick the lowest numbered, most extensively
             used one.  The technique of using no reference antenna
             has been found not to work well.
  BADDISK....Disk numbers on which scratch files are not to
             be placed.

EXPLAIN SECTION

SPCAL:  Task to determine effective feed polarization
       parameters for spectral line data.
Documentor: A. J. Kemball
Related Programs: CALIB, LISTR, SPLIT, CLCOR, LPCAL, PCAL

PCAL, SPCAL or LPCAL?

PCAL was designed for the VLA and works well for unresolved
or slightly resolved calibrators with uniform polarization.
LPCAL was designed for VLBI and allows the use of calibrators
that have significant structure and differential polarization
across the source.  It will also handle unpolarized calibrators.
SPCAL was designed for spectral line experiments and solves
for frequency dependent D-terms.  Like PCAL SPCAL demands
an unresolved calibrator.







AIPS