Description

Import ATCA RPFITS files into a MeasurementSet

The data from the ATCA is available from the archive using the RPFITS file format. These files can be imported into CASA with the importatca task. 

#In CASA
#  importatca :: Import ATCA RPFITS file(s) to a MeasurementSet
files               =['*.C1234']        #  Name of input ATCA RPFits file(s)
vis                 = 'c1234.ms'        #  Name of output visibility file
                                        #   (MeasurementSet)
options             =         ''        #  Processing options: birdie, reweight,
                                        #   noxycorr, fastmosaic, hires, noac
                                        #   (comma separated list)
spw                 =       [-1]        #  Specify the spectral windows to use,
                                        #   default=all
nscans              =     [0, 0]        #  Number of scans to skip followed by
                                        #   number of scans to read
lowfreq             =   '0.1GHz'        #  Lowest reference frequency to select
highfreq            =   '999GHz'        #  Highest reference frequency to select
fields              =       ['']        #  List of field names to select
edge                =          8        #  Percentage of edge channels to flag.
                                        #  For combined zooms, this specifies the
                                        #   percentage for a single zoom window

The files parameter can take a string or a list of strings as input and also allows the use of wildcards as shown in the example above.
 
For older ATCA continuum data (before the CABB correlator, April 2009), use options='birdie,reweight' to suppress internally generated RFI. 
 
The options parameter:
  • birdie - (pre-CABB data only) discard edge channels and channels affected by internal RFI
  • reweight - (pre-CABB data only) suppress ringing of RFI spikes by reweighting of the lag spectrum 
  • noxycorr – do not apply the xy phase correction as derived from the switched noise calibration, by default this is applied during loading of the data
  • fastmosaic – use this option if you are loading mosaic data with many pointings and only one or two integrations per pointing; this option changes the tiling of the data to avoid excessive I/O
  • hires – use this option if you have data in time binning mode (as used for pulsars) but you want to make it look like data with very short integration time (no bins)
  • noac  - discard the auto-correlation data
The spw parameter takes a list of integers and can be used to select one or more of the simultaneous frequencies. With CABB there can be up to 34 spectra. The order of the frequency bands in the RPFITS file is: the two continuum bands (0 and 1), followed by the zoom bands for the first frequency and then the zoom bands for the second frequency. Note that this spw parameter does not take a string with wildcards. Use spw=-1 to get all the data.
 
The nscans parameter can be used to select part of a file, e.g., to retrieve a few test scans for a quick look.
 
The lowfreq and highfreq parameters select data based on the reference frequency.
 
The fields parameter selects data based on the field/source name.
 
The edge parameter specifies how many edge channels to discard as a percentage of the number of channels in each band, e.g., the default value of 8 will discard 82 channels from the top and bottom of a 2048 channel spectrum.