def test_against_pytpm_doc_example():
"""
Check that Astropy's Ecliptic systems give answers consistent with pyTPM
Currently this is only testing against the example given in the pytpm docs
"""
fk5_in = SkyCoord('12h22m54.899s', '15d49m20.57s', frame=FK5(equinox='J2000'))
pytpm_out = BarycentricMeanEcliptic(lon=178.78256462*u.deg,
lat=16.7597002513*u.deg,
equinox='J2000')
astropy_out = fk5_in.transform_to(pytpm_out)
assert pytpm_out.separation(astropy_out) < (1*u.arcsec)
def test_against_pytpm_doc_example():
"""
Check that Astropy's Ecliptic systems give answers consistent with pyTPM
Currently this is only testing against the example given in the pytpm docs
"""
fk5_in = SkyCoord('12h22m54.899s', '15d49m20.57s', frame=FK5(equinox='J2000'))
pytpm_out = BarycentricMeanEcliptic(lon=178.78256462*u.deg,
lat=16.7597002513*u.deg,
equinox='J2000')
astropy_out = fk5_in.transform_to(pytpm_out)
assert pytpm_out.separation(astropy_out) < (1*u.arcsec)
def test_arraytransforms():
"""
Test that transforms to/from ecliptic coordinates work on array coordinates
(not testing for accuracy.)
"""
ra = np.ones((4, ), dtype=float) * u.deg
dec = 2 * np.ones((4, ), dtype=float) * u.deg
distance = np.ones((4, ), dtype=float) * u.au
test_icrs = ICRS(ra=ra, dec=dec, distance=distance)
test_gcrs = GCRS(test_icrs.data)
bary_arr = test_icrs.transform_to(BarycentricMeanEcliptic())
assert bary_arr.shape == ra.shape
helio_arr = test_icrs.transform_to(HeliocentricMeanEcliptic())
assert helio_arr.shape == ra.shape
geo_arr = test_gcrs.transform_to(GeocentricMeanEcliptic())
assert geo_arr.shape == ra.shape
# now check that we also can go back the other way without shape problems
bary_icrs = bary_arr.transform_to(ICRS())
assert bary_icrs.shape == test_icrs.shape
helio_icrs = helio_arr.transform_to(ICRS())
assert helio_icrs.shape == test_icrs.shape
geo_gcrs = geo_arr.transform_to(GCRS())
assert geo_gcrs.shape == test_gcrs.shape
def test_roundtrip_scalar():
icrs = ICRS(ra=1 * u.deg, dec=2 * u.deg, distance=3 * u.au)
gcrs = GCRS(icrs.cartesian)
bary = icrs.transform_to(BarycentricMeanEcliptic())
helio = icrs.transform_to(HeliocentricMeanEcliptic())
geo = gcrs.transform_to(GeocentricMeanEcliptic())
bary_icrs = bary.transform_to(ICRS())
helio_icrs = helio.transform_to(ICRS())
geo_gcrs = geo.transform_to(GCRS())
assert quantity_allclose(bary_icrs.cartesian.xyz, icrs.cartesian.xyz)
assert quantity_allclose(helio_icrs.cartesian.xyz, icrs.cartesian.xyz)
assert quantity_allclose(geo_gcrs.cartesian.xyz, gcrs.cartesian.xyz)
def test_ecliptic_heliobary():
"""
Check that the ecliptic transformations for heliocentric and barycentric
at least more or less make sense
"""
icrs = ICRS(1 * u.deg, 2 * u.deg, distance=1.5 * R_sun)
bary = icrs.transform_to(BarycentricMeanEcliptic())
helio = icrs.transform_to(HeliocentricMeanEcliptic())
# make sure there's a sizable distance shift - in 3d hundreds of km, but
# this is 1D so we allow it to be somewhat smaller
assert np.abs(bary.distance - helio.distance) > 1 * u.km
# now make something that's got the location of helio but in bary's frame.
# this is a convenience to allow `separation` to work as expected
helio_in_bary_frame = bary.realize_frame(helio.cartesian)
assert bary.separation(helio_in_bary_frame) > 1 * u.arcmin