compute_approx_psf_size_and_shape¶
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lsst.pipe.tasks.healSparseMappingProperties.compute_approx_psf_size_and_shape(ccd_row, ra, dec, nx=20, ny=20, orderx=2, ordery=2)¶ Compute the approximate psf size and shape.
This routine fits how the psf size and shape varies over a field by approximating with a Chebyshev bounded field.
Parameters: - ccd_row :
lsst.afw.table.ExposureRecord Exposure metadata for a given detector exposure.
- ra :
np.ndarray Right ascension of points to compute size and shape (degrees).
- dec :
np.ndarray Declination of points to compute size and shape (degrees).
- nx :
int, optional Number of sampling points in the x direction.
- ny :
int, optional Number of sampling points in the y direction.
- orderx :
int, optional Chebyshev polynomial order for fit in x direction.
- ordery :
int, optional Chebyshev polynomial order for fit in y direction.
Returns: - psf_array :
np.ndarray Record array with “psf_size”, “psf_e1”, “psf_e2”.
- ccd_row :