Sunspot Band6 Calibration for CASA 4.7

Overview

The portion of the Sunspot_Band6 CASA Guide will cover the calibration of the raw visibility data. To follow this guide you must have downloaded the file Sunspot_Band6_UncalibratedData.tgz from Sunspot_Band6#Obtaining the Data.

Detail of the ALMA observations are provided at Sunspot_Band6

To skip to the image synthesis portion of the guide, see Sunspot_Band6_Imaging_for_CASA_4.7.

This guide is designed for CASA 4.7.

From next, we will show all commands for the calibration. If you do not want to cut-&-paste the commands, you can use the script as described in #Alternative way of the Calibration.

Before Starting the Calibration of Visibility Data

The “Analysis Utilities” package must be used for the calibration of solar raw visibility data. Therefore, before starting the tutorial, you need to install the package to your data-analysis environment. The documents and software of the package can be obtained from the Analysis Utilities page[1].

Unpack the Data

Once the file Sunspot_Band6_UncalibratedData.tgz had been download, unpack it as follows:

 # In a terminal outside CASA
tar -xvzf Sunspot_Band6_UncalibratedData.tgz

cd Sunspot_Band6_UncalibratedData


#Start CASA
casa

Confirm your version of CASA

This guide has been written for CASA release 4.7. Please confirm your version before proceeding.

# In Casa
version = casadef.casa_version 
print "You are using " + version 
if (version < '4.7.0'):
  print "YOUR VERSION OF CASA IS TOO OLD FOR THIS GUIDE."
  print "PLEASE UPDATE IT BEFORE PROCEEDING." 
else:
  print "Your version of CASA is appropriate for this guide."

We need to import some scripts we will use during the calibration.

import analysisUtils as aU
es = aU.stuffForScienceDataReduction() 
execfile(“SunRedUtil.py”)

“SunRedUtil.py” is included in the file Sunspot_Band6_UncalibratedData.tgz

Initial Inspection, A priori calibration

We start by defining the directory name of the ASDM and some directory names of the Measurement Sets (MS) for the calibration.

 #In Casa
asdm ='uid___A002_Xae00c5_X2a8d' mso = asdm + '.ms'
mss = asdm + '_split.ms'
msc = mss + '.cal'

The raw data have been provided to you in the ASDM format. It is the native format of the data produced by the ALMA observatory.

Before we can proceed to the calibration, we will need to convert those data to the CASA MS format. This is done simply with the task importasdm.

#In Casa
importasdm(asdm = asdm, vis = mso, asis='Antenna Station Receiver Source CalAtmosphere CalWVR CorrelatorMode SBSummary CalDevice ')

The usual first step is then to get some basic information about the data. We do this using the task listobs, which will output a detailed summary of each dataset supplied.