sirius.calc_uvw

calc_uvw_chunk(tel_xds, time_str, phase_center_ra_dec, uvw_parms, check_parms=True)[source]

Calculates a chunk of uvw values. This function forms part of a node in a Dask graph. This function can be used on its own if no parallelism is required.

Parameters

  • tel_xds (xr.Dataset) – An xarray dataset of the radio telescope array layout (see zarr files in sirius_data/telescope_layout/data/ for examples).

  • time_str (str np.array, [n_time], 'YYYY-MM-DDTHH:MM:SS.SSS') – Time serie. Example ‘2019-10-03T19:00:00.000’.

  • phase_center_ra_dec (float np.array, [n_time, 2], (singleton: n_time), radians) – Phase center of array.

  • uvw_parms (dict) –

  • uvw_parms['calc_method'] (str, default='astropy', options=['astropy','casa']) – The uvw coordinates can be calculated using the astropy package or the casa measures tool.

  • uvw_parms['auto_corr'] (bool, default=False) – If True autocorrelations are also calculated.

  • check_parms (bool) – Check input parameters and asign defaults.

Returns

  • uvw (float np.array, [n_time,n_baseline,3]) – The uvw coorsdinates in per wavelength units.

  • antenna1 (int np.array, [n_baseline]) – The indices of the first antenna in the baseline pairs.

  • antenna2 (int np.array, [n_baseline]) – The indices of the second antenna in the baseline pairs.