Summarizing your MS (listobs)

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2.2.6 Summarizing your MS (listobs)

Once you import your data into a CASA Measurement Set, you can get a summary of the MS contents with the listobs task.

The inputs are:

#  listobs :: List the summary of a data set in the logger or in a file
vis                 =         ’’        #  Name of input visibility file (MS)
selectdata          =       True        #  Data selection parameters
     field          =         ’’        #  Field names or field index numbers: ’’==>all,
                                        #   field=’0~2,3C286’
     spw            =         ’’        #  spectral-window/frequency/channel
     antenna        =         ’’        #  antenna/baselines: ’’==>all, antenna =’3,VA04’
     timerange      =         ’’        #  time range: ’’==>all,timerange=’09:14:0~09:54:0’
     correlation    =         ’’        #  Select data based on correlation
     scan           =         ’’        #  scan numbers: ’’==>all
     intent         =         ’’        #  Select data based on observation intent: ’’==>all
     feed           =         ’’        #  multi-feed numbers: Not yet implemented
     array          =         ’’        #  (sub)array numbers: ’’==>all
     uvrange        =         ’’        #  uv range: ’’==>all; uvrange =’0~100klambda’, default
                                        #   units=meters
     observation    =         ’’        #  Select data based on observation ID: ’’==>all

verbose             =       True
listfile            =         ’’        #  Name of disk file to write output: ’’==>to terminal
async               =      False        #  If true the taskname must be started using listobs(...)

The summary (of the selected data) will be written to the logger, to the casapy-YYYYMMDD-HHMMSS.log file, and optionally to a file specified in the listfile parameter. For example,

listobs(’n5921.ms’)

results in the logger messages:

================================================================================
           MeasurementSet Name:  /Users/jott/casa/data/3.4-scripts/irc/day2_TDEM0003_10s_norx      MS Version 2
================================================================================
   Observer: Mark J. Mark Claussen     Project: T.B.D.
Observation: EVLA
Data records: 290218       Total integration time = 10016 seconds
   Observed from   26-Apr-2010/03:21:56.0   to   26-Apr-2010/06:08:52.0 (UTC)

   ObservationID = 0         ArrayID = 0
  Date        Timerange (UTC)          Scan  FldId FieldName           nRows   Int(s)   SpwIds      ScanIntent
  26-Apr-2010/03:21:56.0 - 03:23:16.0     5      2 J0954+1743          2720   9.8      [0, 1]
              03:23:44.0 - 03:28:20.0     6      3 IRC+10216           9918   9.64     [0, 1]
              03:28:43.0 - 03:29:49.0     7      2 J0954+1743          2700   8.89     [0, 1]
              03:30:13.0 - 03:34:48.5     8      3 IRC+10216           9918   9.64     [0, 1]
...
              06:06:14.0 - 06:08:52.0    59      7 J1331+3030          5814   9.52     [0, 1]
           (nRows = Total number of rows per scan)
Fields: 4
  ID   Code Name                RA              Decl          Epoch   SrcId nRows
  2    D    J0954+1743          09:54:56.82363 +17.43.31.2224 J2000   2     65326
  3    NONE IRC+10216           09:47:57.38200 +13.16.40.6600 J2000   3     208242
  5    F    J1229+0203          12:29:06.69973 +02.03.08.5982 J2000   5     10836
  7    E    J1331+3030          13:31:08.28798 +30.30.32.9589 J2000   7     5814
Spectral Windows:  (2 unique spectral windows and 1 unique polarization setups)
  SpwID  #Chans Frame Ch1(MHz)    ChanWid(kHz)  TotBW(kHz)  Corrs
  0          64 TOPO  36387.2295  125           8000        RR  RL  LR  LL
  1          64 TOPO  36304.542   125           8000        RR  RL  LR  LL
Sources: 10
  ID   Name                SpwId RestFreq(MHz)  SysVel(km/s)
  0    J1008+0730          0     0.03639232     -0.026
  0    J1008+0730          1     0.03639232     -0.026
  2    J0954+1743          0     0.03639232     -0.026
  2    J0954+1743          1     0.03639232     -0.026
  3    IRC+10216           0     0.03639232     -0.026
  3    IRC+10216           1     0.03639232     -0.026
  5    J1229+0203          0     0.03639232     -0.026
  5    J1229+0203          1     0.03639232     -0.026
  7    J1331+3030          0     0.03639232     -0.026
  7    J1331+3030          1     0.03639232     -0.026
Antennas: 19:
  ID   Name  Station   Diam.    Long.         Lat.
  0    ea01  W09       25.0 m   -107.37.25.2  +33.53.51.0
  1    ea02  E02       25.0 m   -107.37.04.4  +33.54.01.1
  2    ea03  E09       25.0 m   -107.36.45.1  +33.53.53.6
  3    ea04  W01       25.0 m   -107.37.05.9  +33.54.00.5
  4    ea05  W08       25.0 m   -107.37.21.6  +33.53.53.0
  5    ea07  N06       25.0 m   -107.37.06.9  +33.54.10.3
  6    ea08  N01       25.0 m   -107.37.06.0  +33.54.01.8
  7    ea09  E06       25.0 m   -107.36.55.6  +33.53.57.7
  8    ea12  E08       25.0 m   -107.36.48.9  +33.53.55.1
  9    ea15  W06       25.0 m   -107.37.15.6  +33.53.56.4
  10   ea19  W04       25.0 m   -107.37.10.8  +33.53.59.1
  11   ea20  N05       25.0 m   -107.37.06.7  +33.54.08.0
  12   ea21  E01       25.0 m   -107.37.05.7  +33.53.59.2
  13   ea22  N04       25.0 m   -107.37.06.5  +33.54.06.1
  14   ea23  E07       25.0 m   -107.36.52.4  +33.53.56.5
  15   ea24  W05       25.0 m   -107.37.13.0  +33.53.57.8
  16   ea25  N02       25.0 m   -107.37.06.2  +33.54.03.5
  17   ea27  E03       25.0 m   -107.37.02.8  +33.54.00.5
  18   ea28  N08       25.0 m   -107.37.07.5  +33.54.15.8

using the (default) verbose=True option. The most useful extra information that verbose=True gives is the list of the scans in the dataset.

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