compute_scale

stcal.alignment.compute_scale(wcs: WCS, fiducial: tuple | ndarray, disp_axis: int | None = None, pscale_ratio: float | None = None) → float[source]

Compute the scale at the fiducial point on the detector..

Parameters:

  • wcs (WCS) – Reference WCS object from which to compute a scaling factor.

  • fiducial (tuple) – Input fiducial of (RA, DEC) or (RA, DEC, Wavelength) used in calculating reference points.

  • disp_axis (int, None, optional) – Dispersion axis integer. Assumes the same convention as wcsinfo.dispersion_direction

  • pscale_ratio (int, None, optional) – Ratio of output pixel scale to input pixel scale.

Returns:

scale – Scaling factor for x and y or cross-dispersion direction.

Return type:

float