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 Figure 1. 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.