Calibrating a Mosaicked Spectral Line Dataset: Difference between revisions
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This page assumes you have converted your data from native MIRIAD format to a CASA measurement set (MS). | This page assumes you have converted your data from native MIRIAD format to a CASA measurement set (MS). It also assumes that you have put the filename of the original MS into a global CASA variable, e.g., | ||
<source lang="python"> | |||
# In CASA | |||
project='c0xxx' | |||
msfile=project+'.ms' | |||
</source> | |||
== Examining your data == | |||
You'll need some information about the IDs that CASA assigns to your calibrators, sources, and antennas. So if you haven't yet done so, | |||
<source lang="python"> | |||
# In CASA | |||
listobs(vis=msfile) | |||
</source> | |||
You will want to know: | |||
* The FieldId of each of your sources and calibrators. | |||
* The SpwId of each spectral window you want to calibrate. | |||
* The Name (or station, but ''not'' the ID ) of your reference antenna. | |||
[[Image:listobs1a.png | The beginning of the output from listobs.]] | |||
In this case, the flux calibrator (NEPTUNE) is assigned FldId=0, the bandpass calibrator (3C454.3) is assigned FldId=1, the phase calibrator (2038+513) is assigned FldId=2, and the mosaicked source fields are assigned FldId 3 through 51 (that's field='3~51' in python). | |||
[[Image listobs2a.png | The end of the output from listobs.]] | |||
In this case, the narrowband windows are assigned to SpwID of 1 and 2, and you can see that they each have 63 channels. | |||
Revision as of 15:22, 28 December 2009
This page assumes you have converted your data from native MIRIAD format to a CASA measurement set (MS). It also assumes that you have put the filename of the original MS into a global CASA variable, e.g.,
# In CASA
project='c0xxx'
msfile=project+'.ms'
Examining your data
You'll need some information about the IDs that CASA assigns to your calibrators, sources, and antennas. So if you haven't yet done so,
# In CASA
listobs(vis=msfile)
You will want to know:
- The FieldId of each of your sources and calibrators.
- The SpwId of each spectral window you want to calibrate.
- The Name (or station, but not the ID ) of your reference antenna.
In this case, the flux calibrator (NEPTUNE) is assigned FldId=0, the bandpass calibrator (3C454.3) is assigned FldId=1, the phase calibrator (2038+513) is assigned FldId=2, and the mosaicked source fields are assigned FldId 3 through 51 (that's field='3~51' in python).
The end of the output from listobs.
In this case, the narrowband windows are assigned to SpwID of 1 and 2, and you can see that they each have 63 channels.
