Dynamic Spectrum and Imaging

From EOVSA Wiki
Revision as of 14:28, 10 May 2019 by Sjyu (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Before Starting SunCASA

You will likely be running SunCASA from a working directory that has your data on it, or where you want your output to go. It is easier to start from there than changing directory inside SunCASA. Warning: SunCASA does not like a directory that contains spaces in its path. If you have done the installation as instructed above, then there should be an executable script called suncasa in your system path. This script will set up the required environment and run the version of SunCASA that it points to.

You can open up a terminal, cd to your working directory and typing

suncasa

EOVSA data is handled in CASA tables system, known as a Measurement Set (MS). The actual visibility data are stored in a MAIN table that contains a number of rows, each of which is effectively a single timestamp for a single spectral window and a single baseline. Within SunCASA, you will have access to a collection of tools that allow you to explore and utilize the new radio dynamic spectroscopic imaging data from EOVSA.

Get Dynamic Sepctrum with SunCASA

Within SunCASA, you are using IPython to interact with the system. This does not mean extensive python experience is necessary. Basic Python interactions are straightforward, e.g., assigning parameters, importing modules, running functions. The first module we introduce is dspec. This module allows you to generate and visualize a dynamic spectrum from an MS file.

from suncasa.utils import dspec
vis = 'example.ms' # the visbility data 
bl='4&12'  ## specify a baseline between antenna 4 and antenna 12. 
spw='0~7'
specfile = msfile+'.bl4-12.190000-194000.spec.npz'
timeran='17:58:50~17:59:30'
dspec.get_dspec(vis=vis,specfile=specfile,bl=bl,spw=spw,timeran=timeran)
dspec.plt_dspec(specfile=specfile,pol='RR',dmin=1,dmax=12)  #dmin and dmax is used to change color,pol can be selected as 'RR''LL'or'I'

Imaging with SunCASA