def gei_to_hme(geicoord, hmeframe):
"""
Convert from Geocentric Earth Equatorial to Heliocentric Mean Ecliptic
"""
if geicoord.obstime is None:
raise ConvertError("To perform this transformation, the coordinate"
" frame needs a specified `obstime`.")
# Use an intermediate frame of HME at the GEI observation time
int_frame = HeliocentricMeanEcliptic(obstime=geicoord.obstime, equinox=geicoord.equinox)
# Get the Sun-Earth vector in the intermediate frame
sun_earth = HCRS(_sun_earth_icrf(int_frame.obstime), obstime=int_frame.obstime)
sun_earth_int = sun_earth.transform_to(int_frame).cartesian
# Rotate from Earth equatorial to ecliptic
rot_matrix = _rotation_matrix_obliquity(int_frame.equinox)
earth_object_int = geicoord.cartesian.transform(rot_matrix)
# Find the Sun-object vector in the intermediate frame
sun_object_int = sun_earth_int + earth_object_int
int_coord = int_frame.realize_frame(sun_object_int)
# Convert to the final frame through HCRS
return int_coord.transform_to(HCRS(obstime=int_coord.obstime)).transform_to(hmeframe)
def hee_to_hme(heecoord, hmeframe):
"""
Convert from Heliocentric Earth Ecliptic to Heliocentric Mean Ecliptic
"""
int_frame = HeliocentricMeanEcliptic(obstime=heecoord.obstime, equinox=heecoord.obstime)
# Rotate the HEE coord to the intermediate frame
total_matrix = matrix_transpose(_rotation_matrix_hme_to_hee(int_frame))
int_repr = heecoord.cartesian.transform(total_matrix)
int_coord = int_frame.realize_frame(int_repr)
# Convert to the HME frame through HCRS
return int_coord.transform_to(HCRS).transform_to(hmeframe)
def hee_to_hme(heecoord, hmeframe):
"""
Convert from Heliocentric Earth Ecliptic to Heliocentric Mean Ecliptic
"""
if heecoord.obstime is None:
raise ConvertError("To perform this transformation, the coordinate"
" frame needs a specified `obstime`.")
int_frame = HeliocentricMeanEcliptic(obstime=heecoord.obstime, equinox=heecoord.obstime)
# Rotate the HEE coord to the intermediate frame
total_matrix = matrix_transpose(_rotation_matrix_hme_to_hee(int_frame))
int_repr = heecoord.cartesian.transform(total_matrix)
int_coord = int_frame.realize_frame(int_repr)
# Convert to the HME frame through HCRS
return int_coord.transform_to(HCRS(obstime=int_coord.obstime)).transform_to(hmeframe)