healpy.rotator.Rotator.rotate_map_alms

Rotator.rotate_map_alms(self, m, use_pixel_weights=True, lmax=None, mmax=None, datapath=None, verbose=None)

Rotate a HEALPix map to a new reference frame in spherical harmonics space

This is generally the best strategy to rotate/change reference frame of maps. If the input map is band-limited, i.e. it can be represented exactly by a spherical harmonics transform under a specific lmax, the map rotation will be invertible.

Parameters
mnp.ndarray

Input map, 1 map is considered I, 2 maps:[Q,U], 3 maps:[I,Q,U]

other argumentssee map2alm
Returns
m_rotatednp.ndarray

Map in the new reference frame