compute_approx_psf_size_and_shape

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_rowlsst.afw.table.ExposureRecord

Exposure metadata for a given detector exposure.

ranp.ndarray

Right ascension of points to compute size and shape (degrees).

decnp.ndarray

Declination of points to compute size and shape (degrees).

nxint, optional

Number of sampling points in the x direction.

nyint, optional

Number of sampling points in the y direction.

orderxint, optional

Chebyshev polynomial order for fit in x direction.

orderyint, optional

Chebyshev polynomial order for fit in y direction.

Returns:
psf_arraynp.ndarray

Record array with “psf_size”, “psf_e1”, “psf_e2”.