def test_proj_separations():
"""
Test angular separation functionality
"""
c1 = ICRS(ra=0 * u.deg, dec=0 * u.deg)
c2 = ICRS(ra=0 * u.deg, dec=1 * u.deg)
sep = c2.separation(c1)
# returns an Angle object
assert isinstance(sep, Angle)
assert_allclose(sep.degree, 1.)
assert_allclose(sep.arcminute, 60.)
# these operations have ambiguous interpretations for points on a sphere
with pytest.raises(TypeError):
c1 + c2
with pytest.raises(TypeError):
c1 - c2
ngp = Galactic(l=0 * u.degree, b=90 * u.degree)
ncp = ICRS(ra=0 * u.degree, dec=90 * u.degree)
# if there is a defined conversion between the relevant coordinate systems,
# it will be automatically performed to get the right angular separation
assert_allclose(
ncp.separation(ngp.transform_to(ICRS())).degree,
ncp.separation(ngp).degree)
# distance from the north galactic pole to celestial pole
assert_allclose(
ncp.separation(ngp.transform_to(ICRS())).degree, 62.87174758503201)
def test_proj_separations():
"""
Test angular separation functionality
"""
c1 = ICRS(ra=0*u.deg, dec=0*u.deg)
c2 = ICRS(ra=0*u.deg, dec=1*u.deg)
sep = c2.separation(c1)
# returns an Angle object
assert isinstance(sep, Angle)
assert sep.degree == 1
assert_allclose(sep.arcminute, 60.)
# these operations have ambiguous interpretations for points on a sphere
with pytest.raises(TypeError):
c1 + c2
with pytest.raises(TypeError):
c1 - c2
ngp = Galactic(l=0*u.degree, b=90*u.degree)
ncp = ICRS(ra=0*u.degree, dec=90*u.degree)
# if there is a defined conversion between the relevant coordinate systems,
# it will be automatically performed to get the right angular separation
assert_allclose(ncp.separation(ngp.transform_to(ICRS)).degree,
ncp.separation(ngp).degree)
# distance from the north galactic pole to celestial pole
assert_allclose(ncp.separation(ngp.transform_to(ICRS)).degree,
62.87174758503201)
def test_supergalactic():
"""
Check Galactic<->Supergalactic and Galactic<->ICRS conversion.
"""
# Check supergalactic North pole.
npole = Galactic(l=47.37*u.degree, b=+6.32*u.degree)
assert allclose(npole.transform_to(Supergalactic).sgb.deg, +90, atol=1e-9)
# Check the origin of supergalactic longitude.
lon0 = Supergalactic(sgl=0*u.degree, sgb=0*u.degree)
lon0_gal = lon0.transform_to(Galactic)
assert allclose(lon0_gal.l.deg, 137.37, atol=1e-9)
assert allclose(lon0_gal.b.deg, 0, atol=1e-9)
# Test Galactic<->ICRS with some positions that appear in Foley et al. 2008
# (http://adsabs.harvard.edu/abs/2008A%26A...484..143F)
# GRB 021219
supergalactic = Supergalactic(sgl=29.91*u.degree, sgb=+73.72*u.degree)
icrs = SkyCoord('18h50m27s +31d57m17s')
assert supergalactic.separation(icrs) < 0.005 * u.degree
# GRB 030320
supergalactic = Supergalactic(sgl=-174.44*u.degree, sgb=+46.17*u.degree)
icrs = SkyCoord('17h51m36s -25d18m52s')
assert supergalactic.separation(icrs) < 0.005 * u.degree
def test_galactocentric():
# when z_sun=0, transformation should be very similar to Galactic
icrs_coord = ICRS(ra=np.linspace(0, 360, 10) * u.deg,
dec=np.linspace(-90, 90, 10) * u.deg,
distance=1. * u.kpc)
g_xyz = icrs_coord.transform_to(Galactic).cartesian.xyz
with galactocentric_frame_defaults.set('pre-v4.0'):
gc_xyz = icrs_coord.transform_to(Galactocentric(z_sun=0 *
u.kpc)).cartesian.xyz
diff = np.abs(g_xyz - gc_xyz)
assert allclose(diff[0], 8.3 * u.kpc, atol=1E-5 * u.kpc)
assert allclose(diff[1:], 0 * u.kpc, atol=1E-5 * u.kpc)
# generate some test coordinates
g = Galactic(l=[0, 0, 45, 315] * u.deg,
b=[-45, 45, 0, 0] * u.deg,
distance=[np.sqrt(2)] * 4 * u.kpc)
with galactocentric_frame_defaults.set('pre-v4.0'):
xyz = g.transform_to(
Galactocentric(galcen_distance=1. * u.kpc,
z_sun=0. * u.pc)).cartesian.xyz
true_xyz = np.array([[0, 0, -1.], [0, 0, 1], [0, 1, 0], [0, -1, 0]
]).T * u.kpc
assert allclose(xyz.to(u.kpc), true_xyz.to(u.kpc), atol=1E-5 * u.kpc)
# check that ND arrays work
# from Galactocentric to Galactic
x = np.linspace(-10., 10., 100) * u.kpc
y = np.linspace(-10., 10., 100) * u.kpc
z = np.zeros_like(x)
# from Galactic to Galactocentric
l = np.linspace(15, 30., 100) * u.deg
b = np.linspace(-10., 10., 100) * u.deg
d = np.ones_like(l.value) * u.kpc
with galactocentric_frame_defaults.set('latest'):
g1 = Galactocentric(x=x, y=y, z=z)
g2 = Galactocentric(x=x.reshape(100, 1, 1),
y=y.reshape(100, 1, 1),
z=z.reshape(100, 1, 1))
g1t = g1.transform_to(Galactic)
g2t = g2.transform_to(Galactic)
assert_allclose(g1t.cartesian.xyz, g2t.cartesian.xyz[:, :, 0, 0])
g1 = Galactic(l=l, b=b, distance=d)
g2 = Galactic(l=l.reshape(100, 1, 1),
b=b.reshape(100, 1, 1),
distance=d.reshape(100, 1, 1))
g1t = g1.transform_to(Galactocentric)
g2t = g2.transform_to(Galactocentric)
np.testing.assert_almost_equal(g1t.cartesian.xyz.value,
g2t.cartesian.xyz.value[:, :, 0, 0])
def test_supergalactic():
"""
Check Galactic<->Supergalactic and Galactic<->ICRS conversion.
"""
# Check supergalactic North pole.
npole = Galactic(l=47.37*u.degree, b=+6.32*u.degree)
assert allclose(npole.transform_to(Supergalactic).sgb.deg, +90, atol=1e-9)
# Check the origin of supergalactic longitude.
lon0 = Supergalactic(sgl=0*u.degree, sgb=0*u.degree)
lon0_gal = lon0.transform_to(Galactic)
assert allclose(lon0_gal.l.deg, 137.37, atol=1e-9)
assert allclose(lon0_gal.b.deg, 0, atol=1e-9)
# Test Galactic<->ICRS with some positions that appear in Foley et al. 2008
# (http://adsabs.harvard.edu/abs/2008A%26A...484..143F)
# GRB 021219
supergalactic = Supergalactic(sgl=29.91*u.degree, sgb=+73.72*u.degree)
icrs = SkyCoord('18h50m27s +31d57m17s')
assert supergalactic.separation(icrs) < 0.005 * u.degree
# GRB 030320
supergalactic = Supergalactic(sgl=-174.44*u.degree, sgb=+46.17*u.degree)
icrs = SkyCoord('17h51m36s -25d18m52s')
assert supergalactic.separation(icrs) < 0.005 * u.degree
def test_static_matrix_combine_paths():
"""
Check that combined staticmatrixtransform matrices provide the same
transformation as using an intermediate transformation.
This is somewhat of a regression test for #7706
"""
from astropy.coordinates.baseframe import BaseCoordinateFrame
from astropy.coordinates.matrix_utilities import rotation_matrix
class AFrame(BaseCoordinateFrame):
default_representation = r.SphericalRepresentation
default_differential = r.SphericalCosLatDifferential
t1 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'z'),
ICRS, AFrame)
t1.register(frame_transform_graph)
t2 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'z').T,
AFrame, ICRS)
t2.register(frame_transform_graph)
class BFrame(BaseCoordinateFrame):
default_representation = r.SphericalRepresentation
default_differential = r.SphericalCosLatDifferential
t3 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'x'),
ICRS, BFrame)
t3.register(frame_transform_graph)
t4 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'x').T,
BFrame, ICRS)
t4.register(frame_transform_graph)
c = Galactic(123*u.deg, 45*u.deg)
c1 = c.transform_to(BFrame) # direct
c2 = c.transform_to(AFrame).transform_to(BFrame) # thru A
c3 = c.transform_to(ICRS).transform_to(BFrame) # thru ICRS
assert quantity_allclose(c1.lon, c2.lon)
assert quantity_allclose(c1.lat, c2.lat)
assert quantity_allclose(c1.lon, c3.lon)
assert quantity_allclose(c1.lat, c3.lat)
for t_ in [t1, t2, t3, t4]:
t_.unregister(frame_transform_graph)
def test_static_matrix_combine_paths():
"""
Check that combined staticmatrixtransform matrices provide the same
transformation as using an intermediate transformation.
This is somewhat of a regression test for #7706
"""
from astropy.coordinates.baseframe import BaseCoordinateFrame
from astropy.coordinates.matrix_utilities import rotation_matrix
class AFrame(BaseCoordinateFrame):
default_representation = r.SphericalRepresentation
default_differential = r.SphericalCosLatDifferential
t1 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'z'),
ICRS, AFrame)
t1.register(frame_transform_graph)
t2 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'z').T,
AFrame, ICRS)
t2.register(frame_transform_graph)
class BFrame(BaseCoordinateFrame):
default_representation = r.SphericalRepresentation
default_differential = r.SphericalCosLatDifferential
t3 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'x'),
ICRS, BFrame)
t3.register(frame_transform_graph)
t4 = t.StaticMatrixTransform(rotation_matrix(30.*u.deg, 'x').T,
BFrame, ICRS)
t4.register(frame_transform_graph)
c = Galactic(123*u.deg, 45*u.deg)
c1 = c.transform_to(BFrame()) # direct
c2 = c.transform_to(AFrame()).transform_to(BFrame()) # thru A
c3 = c.transform_to(ICRS()).transform_to(BFrame()) # thru ICRS
assert quantity_allclose(c1.lon, c2.lon)
assert quantity_allclose(c1.lat, c2.lat)
assert quantity_allclose(c1.lon, c3.lon)
assert quantity_allclose(c1.lat, c3.lat)
for t_ in [t1, t2, t3, t4]:
t_.unregister(frame_transform_graph)
def test_galactic_fk4():
lines = get_pkg_data_contents('data/galactic_fk4.csv').split('\n')
t = Table.read(lines, format='ascii', delimiter=',', guess=False)
if N_ACCURACY_TESTS >= len(t):
idxs = range(len(t))
else:
idxs = np.random.randint(len(t), size=N_ACCURACY_TESTS)
diffarcsec1 = []
diffarcsec2 = []
for i in idxs:
# Extract row
r = t[int(i)] # int here is to get around a py 3.x astropy.table bug
# Galactic to FK4
c1 = Galactic(l=r['lon_in'] * u.deg, b=r['lat_in'] * u.deg)
c2 = c1.transform_to(FK4(equinox=Time(r['equinox_fk4'], scale='utc')))
# Find difference
diff = angular_separation(c2.ra.radian, c2.dec.radian,
np.radians(r['ra_fk4']),
np.radians(r['dec_fk4']))
diffarcsec1.append(np.degrees(diff) * 3600.)
# FK4 to Galactic
c1 = FK4(ra=r['lon_in'] * u.deg,
dec=r['lat_in'] * u.deg,
obstime=Time(r['obstime'], scale='utc'),
equinox=Time(r['equinox_fk4'], scale='utc'))
c2 = c1.transform_to(Galactic)
# Find difference
diff = angular_separation(c2.l.radian, c2.b.radian,
np.radians(r['lon_gal']),
np.radians(r['lat_gal']))
diffarcsec2.append(np.degrees(diff) * 3600.)
np.testing.assert_array_less(diffarcsec1, TOLERANCE)
np.testing.assert_array_less(diffarcsec2, TOLERANCE)
def test_galactic_fk4():
lines = get_pkg_data_contents('galactic_fk4.csv').split('\n')
t = Table.read(lines, format='ascii', delimiter=',', guess=False)
if N_ACCURACY_TESTS >= len(t):
idxs = range(len(t))
else:
idxs = np.random.randint(len(t), size=N_ACCURACY_TESTS)
diffarcsec1 = []
diffarcsec2 = []
for i in idxs:
# Extract row
r = t[int(i)] # int here is to get around a py 3.x astropy.table bug
# Galactic to FK4
c1 = Galactic(l=r['lon_in']*u.deg, b=r['lat_in']*u.deg)
c2 = c1.transform_to(FK4(equinox=Time(r['equinox_fk4'], scale='utc')))
# Find difference
diff = angular_separation(c2.ra.radian, c2.dec.radian,
np.radians(r['ra_fk4']),
np.radians(r['dec_fk4']))
diffarcsec1.append(np.degrees(diff) * 3600.)
# FK4 to Galactic
c1 = FK4(ra=r['lon_in']*u.deg, dec=r['lat_in']*u.deg,
obstime=Time(r['obstime'], scale='utc'),
equinox=Time(r['equinox_fk4'], scale='utc'))
c2 = c1.transform_to(Galactic)
# Find difference
diff = angular_separation(c2.l.radian, c2.b.radian,
np.radians(r['lon_gal']),
np.radians(r['lat_gal']))
diffarcsec2.append(np.degrees(diff) * 3600.)
np.testing.assert_array_less(diffarcsec1, TOLERANCE)
np.testing.assert_array_less(diffarcsec2, TOLERANCE)
def test_galactocentric():
# when z_sun=0, transformation should be very similar to Galactic
icrs_coord = ICRS(ra=np.linspace(0, 360, 10)*u.deg,
dec=np.linspace(-90, 90, 10)*u.deg,
distance=1.*u.kpc)
g_xyz = icrs_coord.transform_to(Galactic).cartesian.xyz
gc_xyz = icrs_coord.transform_to(Galactocentric(z_sun=0*u.kpc)).cartesian.xyz
diff = np.abs(g_xyz - gc_xyz)
assert allclose(diff[0], 8.3*u.kpc, atol=1E-5*u.kpc)
assert allclose(diff[1:], 0*u.kpc, atol=1E-5*u.kpc)
# generate some test coordinates
g = Galactic(l=[0, 0, 45, 315]*u.deg, b=[-45, 45, 0, 0]*u.deg,
distance=[np.sqrt(2)]*4*u.kpc)
xyz = g.transform_to(Galactocentric(galcen_distance=1.*u.kpc, z_sun=0.*u.pc)).cartesian.xyz
true_xyz = np.array([[0, 0, -1.], [0, 0, 1], [0, 1, 0], [0, -1, 0]]).T*u.kpc
assert allclose(xyz.to(u.kpc), true_xyz.to(u.kpc), atol=1E-5*u.kpc)
# check that ND arrays work
# from Galactocentric to Galactic
x = np.linspace(-10., 10., 100) * u.kpc
y = np.linspace(-10., 10., 100) * u.kpc
z = np.zeros_like(x)
g1 = Galactocentric(x=x, y=y, z=z)
g2 = Galactocentric(x=x.reshape(100, 1, 1), y=y.reshape(100, 1, 1),
z=z.reshape(100, 1, 1))
g1t = g1.transform_to(Galactic)
g2t = g2.transform_to(Galactic)
assert_allclose(g1t.cartesian.xyz, g2t.cartesian.xyz[:, :, 0, 0])
# from Galactic to Galactocentric
l = np.linspace(15, 30., 100) * u.deg
b = np.linspace(-10., 10., 100) * u.deg
d = np.ones_like(l.value) * u.kpc
g1 = Galactic(l=l, b=b, distance=d)
g2 = Galactic(l=l.reshape(100, 1, 1), b=b.reshape(100, 1, 1),
distance=d.reshape(100, 1, 1))
g1t = g1.transform_to(Galactocentric)
g2t = g2.transform_to(Galactocentric)
np.testing.assert_almost_equal(g1t.cartesian.xyz.value,
g2t.cartesian.xyz.value[:, :, 0, 0])