VLA Data Survey

This is a step-by-step tutorial for doing VLA solar data survey.

Preparatory Work

Get the visbility data

The first step of the data survey is to get the visbility data of the the event you are focusing on. Always the origrinal data should be in the the dictionary '/srg/data/evla', you can find the folders named by the date of the event.

The casa task 'listobs' can help to check the basic information of the data, to get the better understanding of each casa task, you can both type the task name followed with a question mark( for example, 'listobs?') in the server or directly google 'nrao casa listobs'.

For each casa task(take the listobs as a example), you can type 'tget listobs' and then 'inp' to get and change the input parameters.

Task listobs can tell some basic information, use the 2012 Mar 10 event as a example,

Make the dynamic spectrum

Select the appropriate baselines

Usually we use the task 'dspec' to make the dynamic spectrum, use get_dspec to create a npz file, the most important input is timerange and baseline. You can use the casa task 'viewer' to check the visbility data( remember when using the viewer, don not select too long timerange).

When coming into the window of viewer.

Better check both the longer baselines and shorter baselines.