View source for Dynamic Spectrum and Imaging


==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 a dynamic spectrum from an MS file, and visualize it. You can select a subset of data by specifying a [https://casa.nrao.edu/Release3.3.0/docs/UserMan/UserMansu112.html time range], [https://casaguides.nrao.edu/index.php/Selecting_Spectral_Windows_and_Channels spectral windows/channels],  [https://casaguides.nrao.edu/index.php/Antenna/Baseline_Selection_Syntax_with_or_without_Autocorrelations antenna baseline]. The selection syntax follows the ''CASA'' convention. More information may be found in the CASA guide of  [https://casa.nrao.edu/Release3.3.0/docs/UserMan/UserMansu112.html time range], [https://casaguides.nrao.edu/index.php/Selecting_Spectral_Windows_and_Channels spectral windows/channels],  [https://casaguides.nrao.edu/index.php/Antenna/Baseline_Selection_Syntax_with_or_without_Autocorrelations antenna baseline] selection pages.

<pre>
from suncasa.utils import dspec as ds

msfile = 'IDB20170821201020-203020.12s.slfcaled.ms'  # the visbility data
specfile = msfile + '.dspec.npz'  ## The output filename of the dynamic spectrum 
bl = ''    ##  antenna selection, leave it blank for selecting all baselines
spw = ''    ## Spectral Windows and Channels selection, leave it blank for selecting all spectral windows
timeran = ''    ## time range selection, leave it blank for selecting the entire time interval
domedian =True    ## select baselines with a median length (0.2~0.8km)
ds.get_dspec(vis=msfile, specfile=specfile, bl=bl, spw=spw, domedian=domedian)
## this step generates a dynamic spectrum and saves it to IDB20170821201020-203020.12s.slfcaled.ms.dspec.npz
ds.plt_dspec(specfile, pol='XXYY')
</pre>
[[file:fig-dspec.png|thumb|center|500px]]

==Imaging with SunCASA ==
cd to your working directory where the measurement sets file is located.
<pre>
from suncasa.utils import qlookplot as ql
msfile = 'IDB20170821201020-203020.12s.slfcaled.ms'
vis = msfile
timerange = '20:21:10~20:21:30'  ## time range selection
spw = '3.4~6.0GHz'  ## Spectral Windows and Channels selection
stokes = 'XXYY'     ## polarizations selection
ql.qlookplot(vis, timerange=timerange, spw=spw, stokes=stokes)
</pre>