def test_horizons_3d():
"""
Test if Horizons properly reads file with 3D coordinates.
We use the satellite that has the same position as Earth.
"""
file_in = os.path.join(dir_2, "earth_position_1.dat")
file_out = os.path.join(dir_2, "earth_position_2.dat")
satellite = mm.SatelliteSkyCoord(file_in)
(times, vec_x, vec_y, vec_z) = np.loadtxt(file_out, unpack=True)
output = satellite.get_satellite_coords(times).cartesian
np.testing.assert_almost_equal(vec_x, output.x)
np.testing.assert_almost_equal(vec_y, output.y)
np.testing.assert_almost_equal(vec_z, output.z)
def get_d_perp(ra_deg, dec_deg, t_0_par, ephemeris_file):
"""
extract D_perp for satellite for given epoch
"""
parameters = {
't_0': t_0_par,
'u_0': 0,
't_E': 100.,
'pi_E_N': 2.**-0.5,
'pi_E_E': 2.**-0.5,
't_0_par': t_0_par
}
params = MM.ModelParameters(parameters)
coords = MM.Coordinates(SkyCoord(ra_deg, dec_deg, unit=u.deg))
satellite = MM.SatelliteSkyCoord(ephemerides_file=ephemeris_file)
ephemeris = satellite.get_satellite_coords([t_0_par])
trajectory = MM.Trajectory([t_0_par],
params,
coords=coords,
parallax={'satellite': True},
satellite_skycoord=ephemeris)
return np.sqrt(trajectory.x**2 + trajectory.y**2)[0]