py21cmsense.observatory.Observatory.projected_baselines

Observatory.projected_baselines(baselines: ~astropy.units.quantity.Annotated[~astropy.units.quantity.Quantity, PhysicalType('length')] | None = None, time_offset: ~astropy.units.quantity.Annotated[~astropy.units.quantity.Quantity, PhysicalType('time')] = <Quantity 0. h>, phase_center_dec: ~astropy.units.quantity.Annotated[~astropy.units.quantity.Quantity, PhysicalType('angle')] | None = None) → ndarray[source]

Compute the projected baseline lengths (in wavelengths).

Phased to a point that has rotated off zenith by some time_offset.

Parameters:

  • baselines – The baseline co-ordinates to project, assumed to be in metres. If not provided, uses all baselines of the observatory. Shape of the array can be (N,N,3) or (N, 3). The co-ordinates are expected to be in ENU.

  • time_offset – The amount of time elapsed since the phase center was at zenith. Assumed to be in days unless otherwise defined. May be negative.

  • phase_center_dec – The declination of the phase center of the observation. By default, the same as the latitude of the array.

Returns:

  • An array the same shape as baselines_metres, but phased to the

  • new phase centre.