General descriptions

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The following are some cautions when using this import feature.

It is important to specify the antenna parameter when importing Measurement Set. For example:
CASA<1>: scans = sd.scantable( ’OrionS_rawACSmod’, average=False, antenna=0 )

The value of the antenna parameter can be either id (integer) or name (string). The default value for antenna parameter is 0.
It is important to use the average=False parameter setting as the calibration routines supporting GBT data require all of the individual times and phases.
GBT data may need some pre-processing prior to using ASAP. In particular, the program which converts GBT raw data into CASA Measurement Sets tends to proliferate the number of spectral windows due to shifts in the tracking frequency; this is being worked on by GBT staff.
Identification of observing modes or reference and source data are changed from the name assignment to the identification number assignment. Position switched (’_ps’), Nod (’_nod’), and frequency switched (’_fs’) data are assigned their id number as 0, 2, and 3, respectively. The corresponding reference data (name with ’r’) for position switched and frequency switched modes are assigned as 1 and 4, respectively. These identification number is stored as SRCTYPE in the scantable.
Importing of Nobeyama Radio Observatory (NRO) data (in both OTF and NEWSTAR format) is now available. However, it is still experimental and only tested to work from toolkit level.

More information about CASA may be found at the CASA web page