importatca

importatca(files='', vis='', options='', spw=[-1], nscans=[0, 0], lowfreq=0.1, highfreq=999, fields='', edge=8)[source]

Import ATCA RPFITS file(s) to a measurement set

[Description] [Examples] [Development] [Details]

Parameters

files (pathVec=’’) - Name of input ATCA RPFits file(s)
vis (string=’’) - Name of output MeasurementSet
options (string=’’) - Processing options: birdie, reweight, noxycorr, fastmosaic, hires, noac (comma separated list)
spw (intVec=[-1]) - Select spectral window/channels
nscans (intVec=[0, 0]) - Number of scans to skip followed by number of scans to read
lowfreq (double=0.1) - Lowest reference frequency to select
highfreq (double=999) - Highest reference frequency to select
fields (stringVec=’’) - List of field names to select
edge (double=8) - Percentage of edge channels to flag. For combined zooms, this specifies the percentage for a single zoom window

Description

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.

Note: For 16cm CABB data with two identical frequency setups you need to set either spw=[0] or spw=[1], otherwise duplicate data will appear in the MeasurementSet which can cause issues with e.g., mstransform operations.

Examples

Reading a pre-CABB ATCA archive file (RPFITS format)

importatca(['2001-01-02_1*.C999','2001-01-03_0*.C999'],'c999.ms',options='birdie,reweight',edge=10)

Imports a number of ATCA RPFITS-format data sets into a CASA measurement set. We are applying birdie flagging and lag spectrum re-weighting (as appropriate for old 33 channel continuum data), as well as flagging the 10% edge channels.

Reading an ATCA/CABB archive file (RPFITS format)

importatca(['2012-10-25_0707.C2728'],'c2728.ms',options='noac',spw=2,edge=5)

Imports a CABB RPFITS file, throwing away the auto-correlations and the 5% edge channels and selecting only the second simultaneous frequency band.

Development: No additional development details

Parameter Details: Detailed descriptions of each function parameter

files (pathVec='') - Name of input ATCA RPFits file(s)

vis (string='') - Name of output MeasurementSet

Default: none

Example: vis=’mydata.ms’

options (string='') - Processing options

Default: none

Options: birdie, reweight, noxycorr, fastmosaic,

hires, noac (comma separated list)

- 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

spw (intVec=[-1]) - Select spectral window/channels

Default: ‘’ (all spectral windows and channels)

Examples:
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 - chans 3 to 45.
spw=’0~2:2~6’; spw 0,1,2 with channels 2
through 6 in each.
spw = ‘*:3~64’  channels 3 through 64 for all sp id’s
spw = ‘ :3~64’ will NOT work.

nscans (intVec=[0, 0]) - Number of scans to skip followed by number of scans to

read

Default: [0, 0]

lowfreq (double=0.1) - Lowest reference frequency to select

Default: 0.1GHz

highfreq (double=999) - Highest reference frequency to select

Default: 999GHz

fields (stringVec='') - List of field names to select

edge (double=8) - The edge parameter specifies how many edge channels to

discard as a percentage of the number of channels in each band.

Default: 8 (e.g., discard 82 channels from the
top and bottom of a 2048 channel spectrum)
For combined zooms, this specifies the percentage
for a single zoom window