Parameter uvtaper

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5.2.10 Parameter uvtaper

This controls the radial weighting of visibilities in the uv-plane (see § 5.2.11 below) through the multiplication of the visibilities by the Fourier transform of an elliptical Gaussian. This is itself a Gaussian, and thus the visibilities are “tapered” with weights decreasing as a function of uv-radius.

The uvtaper parameter expands the menu upon setting uvtaper=True to reveal the following sub-parameters:

uvtaper       =       True   #  Apply additional uv tapering of  visibilities.
   outertaper =         []   #  uv-taper on outer baselines in uv-plane
   innertaper =         []   #  uv-taper in center of uv-plane (not
implemented)

The sub-parameters specify the size and optionally shape and orientation of this Gaussian in the uv-plane or optionally the sky plane. The outertaper refers to a Gaussian centered on the origin of the uv-plane.

Some examples:

   outertaper=[]                                  # no outer taper applied
   outertaper=[’5klambda’]                        # circular uv taper FWHM=5 kilo-lambda
   outertaper=[’5klambda’,’3klambda’,’45.0deg’]   # elliptical Gaussian
   outertaper=[’10arcsec’]                        # on-sky FWHM 10"
   outertaper=[’300.0’]                           # 300m in aperture plane

Note that if no units are given on the taper, then the default units are assumed to be meters in aperture plane.

ALERT: The innertaper option is not yet implemented.

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