au.gjincBeam(frequency, pixelsize=10, diameter=12.0, xSamplesPerBeam=5.0, ySamplesPerBeam=None, xSamplingArcsec=None, ySamplingArcsec=None, makeplot=False, taper=10.0, geometricMean=False, obscuration=0.75, widthMultiplier=1.0, useCasaJinc=False, testOption=False, minlevels=[0.0], truncate=True, img=None, row=None, column=None, stokes='XX', plotfile='', verbose=False, fwhmfactor=None, excludeBand3=True, excludeBand3Below=109.0)

- frequency: floating point number in GHz (no units) or a string with 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
- makeplot: if True, then also generate a plot
- taper: the illumination taper (in dB) to pass to au.primaryBeamArcsec
- fwhmfactor: if specified, pass this to au.primaryBeamArcsec, overriding taper
- obscuration: diameter in m to pass to au.primaryBeamArcsec
- geometricMean: if True, then return only the geometric mean beamsize; otherwise, return minorAxis,majorAxis,geometricMean (if the sampling is provided in both axes)
- widthMultiplier: the value by which to multiply the default values of gwidth/jwidth
- useCasaJinc: if True, then use grdjinc1 which was extracted from CASA (which uses an approximate formula). If False, use scipy (which is more accurate). The results are nearly identical.
- testOption: not currently used
- minlevels: a list of fractional values (from 0..1) above which to perform 1D Gaussian fits on the estimated restoring beam
- truncate: only used if taper=0, sets whether to truncate the Airy at the first null
- img: if not none, then use a row or column from this image as the beam model
- row: the row of img to use as the starting beam profile model
- column: the column of img to use as the starting beam profile model
- stokes: 'XX','YY' which Stokes to use in the img
- excludeBand3: if True, then don't use Band 3 TICRA patterns below excludeBand3Below'
- excludeBand3Below: frequency in GHz below which to not use Band 3 patterns

- If only the X-axis sampling is given:
- the FWHM of the restoring beam
- the FWHM of a Gaussian fit to the restoring beam

- If both X and Y-axis sampling is given: * If geometricMean=True: * the FWHM of the predicted restoring beam * the FWHM of a Gaussian fit to the predicted restoring beam * If geometricMean=False: * the minor axis of the restoring beam * the major axis of the restoring beam * the geometric mean of the restoring beam computed using findFWHM() * the geometric mean of the FWHM of a Gaussian fit to the restoring beam

CASA <12>: au.gjincBeam(115.27,pixelsize=3,taper=10) Out[6]: (51.287757483793229, 51.286676672022502) CASA <14>: au.gjincBeam(336.5,pixelsize=3,taper=10,xSamplingArcsec=3.5,ySamplingArcsec=5.7,makeplot=T) Plot left in gjincBeam.png Out[14]: (18.226274978160909, 18.488102385966258, 18.356721872682328, 18.35236509861296)

- gjincBeam.png:

- A comparison of the grdjinc1 function from casa, and scipy's implementation, which is used in this function.

I | Attachment | Action | Size | Date | Who | Comment |
---|---|---|---|---|---|---|

png | gjincBeam.png | manage | 101 K | 2013-11-15 - 14:03 | ToddHunter | |

png | jinc1_comparison.png | manage | 55 K | 2013-11-15 - 14:28 | ToddHunter | made with au v1.1481 |

This topic: ALMA > TWikiUsers > ToddHunter > CasaExtensions > GjincBeam

Topic revision: 2014-03-27, ToddHunter

Topic revision: 2014-03-27, ToddHunter

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