Difference between revisions of "Dynamic Spectrum and Imaging"

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(Get Dynamic Sepctrum with SunCASA)
(Get Dynamic Sepctrum with SunCASA)
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from suncasa.utils import dspec as ds
 
from suncasa.utils import dspec as ds
  
msfile = 'IDB20170821201020-203020.12s.slfcaled.ms' # the visbility data
+
# define the visbility data file
specfile = msfile + '.dspec.npz'  ## The output filename of the dynamic spectrum
+
msfile = 'IDB20170821201020-203020.12s.slfcaled.ms'  
 +
 
 +
## define the output filename of the dynamic spectrum
 +
specfile = msfile + '.dspec.npz'   
 +
 
 
##  antenna selection
 
##  antenna selection
 
## leave it blank for selecting all baselines
 
## leave it blank for selecting all baselines
 
bl = ''
 
bl = ''
 +
 
## Spectral Windows and Channels selection
 
## Spectral Windows and Channels selection
 
leave it blank for selecting all spectral windows
 
leave it blank for selecting all spectral windows
 
spw = ''
 
spw = ''
 +
 
## time range selection
 
## time range selection
 
## leave it blank for selecting the entire time interval
 
## leave it blank for selecting the entire time interval
 
timeran = ''
 
timeran = ''
 +
 
## select baselines with a median length (0.2~0.8km)
 
## select baselines with a median length (0.2~0.8km)
 
domedian =True     
 
domedian =True     
 +
 
## this step generates a dynamic spectrum and saves it to IDB20170821201020-203020.12s.slfcaled.ms.dspec.npz
 
## this step generates a dynamic spectrum and saves it to IDB20170821201020-203020.12s.slfcaled.ms.dspec.npz
 
ds.get_dspec(vis=msfile, specfile=specfile, bl=bl, spw=spw, domedian=domedian)
 
ds.get_dspec(vis=msfile, specfile=specfile, bl=bl, spw=spw, domedian=domedian)
  
 +
## this plot the dynamic spectrum.
 
ds.plt_dspec(specfile, pol='XXYY')
 
ds.plt_dspec(specfile, pol='XXYY')
 
</pre>
 
</pre>

Revision as of 14:59, 15 May 2019

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 time range, spectral windows/channels, antenna baseline. The selection syntax follows the CASA convention. More information may be found in the CASA guide of time range, spectral windows/channels, antenna baseline selection pages.

from suncasa.utils import dspec as ds

# define the visbility data file
msfile = 'IDB20170821201020-203020.12s.slfcaled.ms' 

## define the output filename of the dynamic spectrum 
specfile = msfile + '.dspec.npz'  

##  antenna selection
## leave it blank for selecting all baselines
bl = ''

## Spectral Windows and Channels selection
leave it blank for selecting all spectral windows
spw = ''

## time range selection
## leave it blank for selecting the entire time interval
timeran = ''

## select baselines with a median length (0.2~0.8km)
domedian =True    

## this step generates a dynamic spectrum and saves it to IDB20170821201020-203020.12s.slfcaled.ms.dspec.npz
ds.get_dspec(vis=msfile, specfile=specfile, bl=bl, spw=spw, domedian=domedian)

## this plot the dynamic spectrum.
ds.plt_dspec(specfile, pol='XXYY')
Fig-dspec.png

Imaging with SunCASA

cd to your working directory where the measurement sets file is located.

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)