def true_helioecliptic_to_icrs(from_coo, to_frame):
if not u.m.is_equivalent(from_coo.cartesian.x.unit):
raise UnitsError(_NEED_ORIGIN_HINT.format(from_coo.__class__.__name__))
# first un-precess from ecliptic to ICRS orientation
rmat = _true_ecliptic_rotation_matrix(from_coo.equinox)
# now offset back to barycentric, which is the correct center for ICRS
sun_from_ssb = get_offset_sun_from_barycenter(
from_coo.obstime, include_velocity=bool(from_coo.data.differentials))
return matrix_transpose(rmat), sun_from_ssb
def icrs_to_true_helioecliptic(from_coo, to_frame):
if not u.m.is_equivalent(from_coo.cartesian.x.unit):
raise UnitsError(_NEED_ORIGIN_HINT.format(from_coo.__class__.__name__))
# get the offset of the barycenter from the Sun
ssb_from_sun = get_offset_sun_from_barycenter(to_frame.obstime, reverse=True,
include_velocity=bool(from_coo.data.differentials))
# now compute the matrix to precess to the right orientation
rmat = _true_ecliptic_rotation_matrix(to_frame.equinox)
return rmat, ssb_from_sun.transform(rmat)
def icrs_to_true_helioecliptic(from_coo, to_frame):
if not u.m.is_equivalent(from_coo.cartesian.x.unit):
raise UnitsError(_NEED_ORIGIN_HINT.format(from_coo.__class__.__name__))
# get barycentric sun coordinate
# this goes here to avoid circular import errors
from astropy.coordinates.solar_system import get_body_barycentric
bary_sun_pos = get_body_barycentric('sun', to_frame.obstime)
# now compute the matrix to precess to the right orientation
rmat = _true_ecliptic_rotation_matrix(to_frame.equinox)
return rmat, (-bary_sun_pos).transform(rmat)
def true_helioecliptic_to_icrs(from_coo, to_frame):
if not u.m.is_equivalent(from_coo.cartesian.x.unit):
raise UnitsError(_NEED_ORIGIN_HINT.format(from_coo.__class__.__name__))
# first un-precess from ecliptic to ICRS orientation
rmat = _true_ecliptic_rotation_matrix(from_coo.equinox)
# now offset back to barycentric, which is the correct center for ICRS
# this goes here to avoid circular import errors
from astropy.coordinates.solar_system import get_body_barycentric
# get barycentric sun coordinate
bary_sun_pos = get_body_barycentric('sun', from_coo.obstime)
return matrix_transpose(rmat), bary_sun_pos