GjincBeam

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This page documents the gjincBeam function of the Python module analysisUtils.

This function calls the gjinc class to compute the effective restoring beam obtained from the casa command sd_imaging when using the GJINC gridding kernel assuming the GJINC specific parameters are left at their default values. It returns the value in arc seconds.

Usage

au.gjincBeam(frequency, pixelsize=10, diameter=12.0, samplingFactor=2.5)

   frequency: floating point number in GHz (no units)
   pixelsize: floating point number in arcseconds (no units)
   diameter: the diameter of the single dish antenna in meters (no units)
   xSamplesPerBeam: the number of sampled points per telescope FWHM beam along the X axis
   ySamplesPerBeam: the number of sampled points per telescope FWHM beam along the Y axis
   xSamplingArcsec: if not None, then use this value instead of xSamplesPerBeam
   ySamplingArcsec: if not None, then use this value instead of ySamplesPerBeam 

Examples

CASA <3>: au.gjincBeam(115.27)
Theoretical primary beam FWHP = 52.3039 arcsec
Sampled every 10.4608 arcsec (5.000000 points per beam)
Expected effective restoring beam = 54.2091 arcsec
  Out[3]: 54.209121599085897

CASA <5>: au.gjincBeam(115.27, xSamplingArcsec=10, ySamplingArcsec=15)
Theoretical primary beam FWHP = 52.3039 arcsec
Sampled every 10 arcsec (5.23039 points per beam) in X
Sampled every 15 arcsec (3.48693 points per beam) in Y
Expected effective restoring beam along X = 54.1741 arcsec
Expected effective restoring beam along Y = 54.5878 arcsec
Geometric mean = 54.3805 arcsec
  Out[5]: 54.380521837034024

Example

# In CASA
CASA <3>: import analysisUtils as au
au.gjincBeam(115.27)
Theoretical primary beam FWHP = 52.3039 arcsec
Expected effective restoring beam = 55.6189 arcsec
  Out[3]: 55.61890766200338