Sunspot Band6 Imaging for CASA 4.7

Overview

This portion of the Sunspot Band6 CASA Guide for CASA 4.7 will cover the image synthesis of a sunspot. It begins where Sunspot_Band6_Calibration_for_CASA_4.7 is completed. In the case, we assume that you are working on the working directory ‘Sunspot_Band6_UncalibratedData’.

If you did not complete the Calibration portion of the guide, the you can download the calibrated visibility data by click on the region closed to your location:

East Asia

Eurpoe

North Amrica

Once the download has finished, unpack the file:

# In a terminal outside CASA
tar -xvzf Sunspot_Band6_CalibratedData.tgz

cd Sunspot_Band6_CalibratedData

#Start CASA
casa

From next, we will show all commands for solar image synthesis. If you do not want to cut-&-past the commands, you can use the script as described in #Alternative way of Imaging.

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."

Flagging of the surplus scans

<figure id="fieldid">

<xr id="fieldid" nolink/> The plot of the FieldID of the scans as a function of the time.

</figure>

The actual duration of the observations does not exactly equal to the required duration of the 149-poinitng MOSAIC. Hence, some fields were observed twice, as shown in <xr id="fieldid"/>. Although the visibility data of the surplus scans are valid, it is better that they are not used for the image synthesis, considering the uniformity of the sensitivity in a map. For the reason, we flagged the surplus scans by the following command.

# In Casa
msc = ‘uid___A002_Xae00c5_X2a8d_split.ms.cal’
flagdata(vis = msc, mode = 'manual', timerange = '2015/12/18/20:02:35~20:08:20', flagbackup = False)