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_lsr_sanity():
# random numbers, but zero velocity in ICRS frame
icrs = ICRS(ra=15.1241*u.deg, dec=17.5143*u.deg, distance=150.12*u.pc,
pm_ra_cosdec=0*u.mas/u.yr, pm_dec=0*u.mas/u.yr,
radial_velocity=0*u.km/u.s)
lsr = icrs.transform_to(LSR())
lsr_diff = lsr.data.differentials['s']
cart_lsr_vel = lsr_diff.represent_as(CartesianRepresentation, base=lsr.data)
lsr_vel = ICRS(cart_lsr_vel)
gal_lsr = lsr_vel.transform_to(Galactic()).cartesian.xyz
assert allclose(gal_lsr.to(u.km/u.s, u.dimensionless_angles()),
lsr.v_bary.d_xyz)
# moving with LSR velocity
lsr = LSR(ra=15.1241*u.deg, dec=17.5143*u.deg, distance=150.12*u.pc,
pm_ra_cosdec=0*u.mas/u.yr, pm_dec=0*u.mas/u.yr,
radial_velocity=0*u.km/u.s)
icrs = lsr.transform_to(ICRS())
icrs_diff = icrs.data.differentials['s']
cart_vel = icrs_diff.represent_as(CartesianRepresentation, base=icrs.data)
vel = ICRS(cart_vel)
gal_icrs = vel.transform_to(Galactic()).cartesian.xyz
assert allclose(gal_icrs.to(u.km/u.s, u.dimensionless_angles()),
-lsr.v_bary.d_xyz)
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_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])
def test_setitem_exceptions():
from astropy.coordinates.builtin_frames import FK4, Galactic
obstime = 'B1950'
sc0 = FK4([1, 2]*u.deg, [3, 4]*u.deg)
sc2 = FK4([10, 20]*u.deg, [30, 40]*u.deg, obstime=obstime)
sc1 = Galactic(sc0.ra, sc0.dec)
with pytest.raises(TypeError, match='can only set from object of same class: '
'Galactic vs. FK4'):
sc1[0] = sc2[0]
sc1 = FK4(sc0.ra, sc0.dec, obstime='B2001')
with pytest.raises(ValueError, match='can only set frame item from an equivalent frame'):
sc1[0] = sc2[0]
sc1 = FK4(sc0.ra[0], sc0.dec[0], obstime=obstime)
with pytest.raises(TypeError, match="scalar 'FK4' frame object does not support "
'item assignment'):
sc1[0] = sc2[0]
sc1 = FK4(obstime=obstime)
with pytest.raises(ValueError, match='cannot set frame which has no data'):
sc1[0] = sc2[0]
sc1 = FK4(sc0.ra, sc0.dec, obstime=[obstime, 'B1980'])
with pytest.raises(ValueError, match='can only set frame item from an equivalent frame'):
sc1[0] = sc2[0]
# Wrong shape
sc1 = FK4([sc0.ra], [sc0.dec], obstime=[obstime, 'B1980'])
with pytest.raises(ValueError, match='can only set frame item from an equivalent frame'):
sc1[0] = sc2[0]
def test_fk5_galactic():
"""
Check that FK5 -> Galactic gives the same as FK5 -> FK4 -> Galactic.
"""
fk5 = FK5(ra=1*u.deg, dec=2*u.deg)
direct = fk5.transform_to(Galactic())
indirect = fk5.transform_to(FK4()).transform_to(Galactic())
assert direct.separation(indirect).degree < 1.e-10
direct = fk5.transform_to(Galactic())
indirect = fk5.transform_to(FK4NoETerms()).transform_to(Galactic())
assert direct.separation(indirect).degree < 1.e-10
def test_api():
# transform observed Barycentric velocities to full-space Galactocentric
with galactocentric_frame_defaults.set('latest'):
gc_frame = Galactocentric()
icrs = ICRS(ra=151. * u.deg,
dec=-16 * u.deg,
distance=101 * u.pc,
pm_ra_cosdec=21 * u.mas / u.yr,
pm_dec=-71 * u.mas / u.yr,
radial_velocity=71 * u.km / u.s)
icrs.transform_to(gc_frame)
# transform a set of ICRS proper motions to Galactic
icrs = ICRS(ra=151. * u.deg,
dec=-16 * u.deg,
pm_ra_cosdec=21 * u.mas / u.yr,
pm_dec=-71 * u.mas / u.yr)
icrs.transform_to(Galactic())
# transform a Barycentric RV to a GSR RV
icrs = ICRS(ra=151. * u.deg,
dec=-16 * u.deg,
distance=1. * u.pc,
pm_ra_cosdec=0 * u.mas / u.yr,
pm_dec=0 * u.mas / u.yr,
radial_velocity=71 * u.km / u.s)
icrs.transform_to(Galactocentric())
def test_all_arg_options(kwargs):
# Above is a list of all possible valid combinations of arguments.
# Here we do a simple thing and just verify that passing them in, we have
# access to the relevant attributes from the resulting object
icrs = ICRS(**kwargs)
gal = icrs.transform_to(Galactic())
repr_gal = repr(gal)
for k in kwargs:
if k == 'differential_type':
continue
getattr(icrs, k)
if 'pm_ra_cosdec' in kwargs: # should have both
assert 'pm_l_cosb' in repr_gal
assert 'pm_b' in repr_gal
assert 'mas / yr' in repr_gal
if 'radial_velocity' not in kwargs:
assert 'radial_velocity' not in repr_gal
if 'radial_velocity' in kwargs:
assert 'radial_velocity' in repr_gal
assert 'km / s' in repr_gal
if 'pm_ra_cosdec' not in kwargs:
assert 'pm_l_cosb' not in repr_gal
assert 'pm_b' not in repr_gal
def test_skyoffset_names():
origin1 = ICRS(45 * u.deg, 45 * u.deg)
aframe1 = SkyOffsetFrame(origin=origin1)
assert type(aframe1).__name__ == 'SkyOffsetICRS'
origin2 = Galactic(45 * u.deg, 45 * u.deg)
aframe2 = SkyOffsetFrame(origin=origin2)
assert type(aframe2).__name__ == 'SkyOffsetGalactic'
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_faux_fk5_galactic():
from astropy.coordinates.builtin_frames.galactic_transforms import fk5_to_gal, _gal_to_fk5
class Galactic2(Galactic):
pass
dt = 1000 * u.s
@frame_transform_graph.transform(FunctionTransformWithFiniteDifference,
FK5,
Galactic2,
finite_difference_dt=dt,
symmetric_finite_difference=True,
finite_difference_frameattr_name=None)
def fk5_to_gal2(fk5_coo, gal_frame):
trans = DynamicMatrixTransform(fk5_to_gal, FK5, Galactic2)
return trans(fk5_coo, gal_frame)
@frame_transform_graph.transform(FunctionTransformWithFiniteDifference,
Galactic2,
ICRS,
finite_difference_dt=dt,
symmetric_finite_difference=True,
finite_difference_frameattr_name=None)
def gal2_to_fk5(gal_coo, fk5_frame):
trans = DynamicMatrixTransform(_gal_to_fk5, Galactic2, FK5)
return trans(gal_coo, fk5_frame)
c1 = FK5(ra=150 * u.deg,
dec=-17 * u.deg,
radial_velocity=83 * u.km / u.s,
pm_ra_cosdec=-41 * u.mas / u.yr,
pm_dec=16 * u.mas / u.yr,
distance=150 * u.pc)
c2 = c1.transform_to(Galactic2())
c3 = c1.transform_to(Galactic())
# compare the matrix and finite-difference calculations
assert quantity_allclose(c2.pm_l_cosb, c3.pm_l_cosb, rtol=1e-4)
assert quantity_allclose(c2.pm_b, c3.pm_b, rtol=1e-4)
def test_create_orderered_data():
from astropy.coordinates.builtin_frames import ICRS, Galactic, AltAz
TOL = 1e-10 * u.deg
i = ICRS(1 * u.deg, 2 * u.deg)
assert (i.ra - 1 * u.deg) < TOL
assert (i.dec - 2 * u.deg) < TOL
g = Galactic(1 * u.deg, 2 * u.deg)
assert (g.l - 1 * u.deg) < TOL
assert (g.b - 2 * u.deg) < TOL
a = AltAz(1 * u.deg, 2 * u.deg)
assert (a.az - 1 * u.deg) < TOL
assert (a.alt - 2 * u.deg) < TOL
with pytest.raises(TypeError):
ICRS(1 * u.deg, 2 * u.deg, 1 * u.deg, 2 * u.deg)
with pytest.raises(TypeError):
sph = r.SphericalRepresentation(1 * u.deg, 2 * u.deg, 3 * u.kpc)
ICRS(sph, 1 * u.deg, 2 * u.deg)
def test_xhip_galactic(hip, ra, dec, pmra, pmdec, glon, glat, dist, pmglon,
pmglat, rv, U, V, W):
i = ICRS(ra * u.deg,
dec * u.deg,
dist * u.pc,
pm_ra_cosdec=pmra * u.marcsec / u.yr,
pm_dec=pmdec * u.marcsec / u.yr,
radial_velocity=rv * u.km / u.s)
g = i.transform_to(Galactic())
# precision is limited by 2-deciimal digit string representation of pms
assert quantity_allclose(g.pm_l_cosb,
pmglon * u.marcsec / u.yr,
atol=.01 * u.marcsec / u.yr)
assert quantity_allclose(g.pm_b,
pmglat * u.marcsec / u.yr,
atol=.01 * u.marcsec / u.yr)
# make sure UVW also makes sense
uvwg = g.cartesian.differentials['s']
# precision is limited by 1-decimal digit string representation of vels
assert quantity_allclose(uvwg.d_x, U * u.km / u.s, atol=.1 * u.km / u.s)
assert quantity_allclose(uvwg.d_y, V * u.km / u.s, atol=.1 * u.km / u.s)
assert quantity_allclose(uvwg.d_z, W * u.km / u.s, atol=.1 * u.km / u.s)
def test_distances():
"""
Tests functionality for Coordinate class distances and cartesian
transformations.
"""
'''
Distances can also be specified, and allow for a full 3D definition of a
coordinate.
'''
# try all the different ways to initialize a Distance
distance = Distance(12, u.parsec)
Distance(40, unit=u.au)
Distance(value=5, unit=u.kpc)
# need to provide a unit
with pytest.raises(u.UnitsError):
Distance(12)
# standard units are pre-defined
npt.assert_allclose(distance.lyr, 39.138765325702551)
npt.assert_allclose(distance.km, 370281309776063.0)
# Coordinate objects can be assigned a distance object, giving them a full
# 3D position
c = Galactic(l=158.558650 * u.degree,
b=-43.350066 * u.degree,
distance=Distance(12, u.parsec))
# or initialize distances via redshifts - this is actually tested in the
# function below that checks for scipy. This is kept here as an example
# c.distance = Distance(z=0.2) # uses current cosmology
# with whatever your preferred cosmology may be
# c.distance = Distance(z=0.2, cosmology=WMAP5)
# Coordinate objects can be initialized with a distance using special
# syntax
c1 = Galactic(l=158.558650 * u.deg,
b=-43.350066 * u.deg,
distance=12 * u.kpc)
# Coordinate objects can be instantiated with cartesian coordinates
# Internally they will immediately be converted to two angles + a distance
cart = CartesianRepresentation(x=2 * u.pc, y=4 * u.pc, z=8 * u.pc)
c2 = Galactic(cart)
sep12 = c1.separation_3d(c2)
# returns a *3d* distance between the c1 and c2 coordinates
# not that this does *not*
assert isinstance(sep12, Distance)
npt.assert_allclose(sep12.pc, 12005.784163916317, 10)
'''
All spherical coordinate systems with distances can be converted to
cartesian coordinates.
'''
cartrep2 = c2.cartesian
assert isinstance(cartrep2.x, u.Quantity)
npt.assert_allclose(cartrep2.x.value, 2)
npt.assert_allclose(cartrep2.y.value, 4)
npt.assert_allclose(cartrep2.z.value, 8)
# with no distance, the unit sphere is assumed when converting to cartesian
c3 = Galactic(l=158.558650 * u.degree,
b=-43.350066 * u.degree,
distance=None)
unitcart = c3.cartesian
npt.assert_allclose(
((unitcart.x**2 + unitcart.y**2 + unitcart.z**2)**0.5).value, 1.0)
# TODO: choose between these when CartesianRepresentation gets a definite
# decision on whether or not it gets __add__
#
# CartesianRepresentation objects can be added and subtracted, which are
# vector/elementwise they can also be given as arguments to a coordinate
# system
# csum = ICRS(c1.cartesian + c2.cartesian)
csumrep = CartesianRepresentation(c1.cartesian.xyz + c2.cartesian.xyz)
csum = ICRS(csumrep)
npt.assert_allclose(csumrep.x.value, -8.12016610185)
npt.assert_allclose(csumrep.y.value, 3.19380597435)
npt.assert_allclose(csumrep.z.value, -8.2294483707)
npt.assert_allclose(csum.ra.degree, 158.529401774)
npt.assert_allclose(csum.dec.degree, -43.3235825777)
npt.assert_allclose(csum.distance.kpc, 11.9942200501)
def test_celestial_frame_to_wcs():
# Import astropy.coordinates here to avoid circular imports
from astropy.coordinates import ICRS, ITRS, FK5, FK4, FK4NoETerms, Galactic, BaseCoordinateFrame
class FakeFrame(BaseCoordinateFrame):
pass
frame = FakeFrame()
with pytest.raises(ValueError) as exc:
celestial_frame_to_wcs(frame)
assert exc.value.args[0] == ("Could not determine WCS corresponding to "
"the specified coordinate frame.")
frame = ICRS()
mywcs = celestial_frame_to_wcs(frame)
mywcs.wcs.set()
assert tuple(mywcs.wcs.ctype) == ('RA---TAN', 'DEC--TAN')
assert mywcs.wcs.radesys == 'ICRS'
assert np.isnan(mywcs.wcs.equinox)
assert mywcs.wcs.lonpole == 180
assert mywcs.wcs.latpole == 0
frame = FK5(equinox='J1987')
mywcs = celestial_frame_to_wcs(frame)
assert tuple(mywcs.wcs.ctype) == ('RA---TAN', 'DEC--TAN')
assert mywcs.wcs.radesys == 'FK5'
assert mywcs.wcs.equinox == 1987.
frame = FK4(equinox='B1982')
mywcs = celestial_frame_to_wcs(frame)
assert tuple(mywcs.wcs.ctype) == ('RA---TAN', 'DEC--TAN')
assert mywcs.wcs.radesys == 'FK4'
assert mywcs.wcs.equinox == 1982.
frame = FK4NoETerms(equinox='B1982')
mywcs = celestial_frame_to_wcs(frame)
assert tuple(mywcs.wcs.ctype) == ('RA---TAN', 'DEC--TAN')
assert mywcs.wcs.radesys == 'FK4-NO-E'
assert mywcs.wcs.equinox == 1982.
frame = Galactic()
mywcs = celestial_frame_to_wcs(frame)
assert tuple(mywcs.wcs.ctype) == ('GLON-TAN', 'GLAT-TAN')
assert mywcs.wcs.radesys == ''
assert np.isnan(mywcs.wcs.equinox)
frame = Galactic()
mywcs = celestial_frame_to_wcs(frame, projection='CAR')
assert tuple(mywcs.wcs.ctype) == ('GLON-CAR', 'GLAT-CAR')
assert mywcs.wcs.radesys == ''
assert np.isnan(mywcs.wcs.equinox)
frame = Galactic()
mywcs = celestial_frame_to_wcs(frame, projection='CAR')
mywcs.wcs.crval = [100, -30]
mywcs.wcs.set()
assert_allclose((mywcs.wcs.lonpole, mywcs.wcs.latpole), (180, 60))
frame = ITRS(obstime=Time('2017-08-17T12:41:04.43'))
mywcs = celestial_frame_to_wcs(frame, projection='CAR')
assert tuple(mywcs.wcs.ctype) == ('TLON-CAR', 'TLAT-CAR')
assert mywcs.wcs.radesys == 'ITRS'
assert mywcs.wcs.dateobs == '2017-08-17T12:41:04.430'
frame = ITRS()
mywcs = celestial_frame_to_wcs(frame, projection='CAR')
assert tuple(mywcs.wcs.ctype) == ('TLON-CAR', 'TLAT-CAR')
assert mywcs.wcs.radesys == 'ITRS'
assert mywcs.wcs.dateobs == Time('J2000').utc.fits
