compute_fiducial

stcal.alignment.compute_fiducial(wcslist: list, bounding_box: tuple | list | None = None) → ndarray

Calculates the world coordinates of the fiducial point of a list of WCS objects. For a celestial footprint this is the center. For a spectral footprint, it is the beginning of its range.

Parameters:

• wcslist (list) – A list containing all the WCS objects for which the fiducial is to be calculated.

• bounding_box (tuple, list, None) – The bounding box over which the WCS is valid. It can be a either tuple of tuples or a list of lists of size 2 where each element represents a range of (low, high) values. The bounding_box is in the order of the axes, axes_order. For two inputs and axes_order(0, 1) the bounding box can be either ((xlow, xhigh), (ylow, yhigh)) or [[xlow, xhigh], [ylow, yhigh]].

Returns:

fiducial – A two-elements array containing the world coordinates of the fiducial point in the combined output coordinate frame.

Return type:

numpy.ndarray

Notes

This function assumes all WCSs have the same output coordinate frame.