generate_psf

ska_sdp_func_python.xradio.imaging.generate_psf(xds: Dataset, backend: InvertBackend, *, num_pixels_l: int, num_pixels_m: int, pixel_size_radians: float) → Dataset

Generate the PSF cube associated with the given xradio visibility dataset, using one of the supported invert backends/gridders. Calls invert with the exact same options, except with visibility values replaced by ones. See notes at the end for details.

Warning

This function is experimental and its interface may change. Natural weighting is used; support for other weighting modes will be added later.

Parameters:

• xds – Input xradio visibility Dataset.

• backend – Configuration options for the invert backend to use, e.g. pass a DuccInvert instance to use DUCC. See invert for available backends.

• num_pixels_l – Number of pixels in the l direction (east-west). Must be an even number.

• num_pixels_m – Number of pixels in the m direction (north-south). Must be an even number.

• pixel_size_radians – The size of a pixel in radians at the centre of the field of view.

Returns:

The resulting PSF as an Image xarray Dataset.

Note

The PSFs for different polarization channels will often be very similar, any differences between them can only be caused by differences in visibility weights. The choice is left to the caller to select only one pol before calling this function, and use that PSF as an approximation for the other pols.