def test_time_inputs():
"""
Test validation and conversion of inputs for equinox and obstime attributes.
"""
from astropy.time import Time
from astropy.coordinates.builtin_frames import FK4
c = FK4(1 * u.deg,
2 * u.deg,
equinox='J2001.5',
obstime='2000-01-01 12:00:00')
assert c.equinox == Time('J2001.5')
assert c.obstime == Time('2000-01-01 12:00:00')
with pytest.raises(ValueError) as err:
c = FK4(1 * u.deg, 2 * u.deg, equinox=1.5)
assert 'Invalid time input' in str(err.value)
with pytest.raises(ValueError) as err:
c = FK4(1 * u.deg, 2 * u.deg, obstime='hello')
assert 'Invalid time input' in str(err.value)
# A vector time should work if the shapes match, but we don't automatically
# broadcast the basic data (just like time).
FK4([1, 2] * u.deg, [2, 3] * u.deg, obstime=['J2000', 'J2001'])
with pytest.raises(ValueError) as err:
FK4(1 * u.deg, 2 * u.deg, obstime=['J2000', 'J2001'])
assert 'shape' in str(err.value)
def test_setitem_velocities():
"""Test different flavors of item setting for a Frame with a velocity.
"""
from astropy.coordinates.builtin_frames import FK4
sc0 = FK4([1, 2]*u.deg, [3, 4]*u.deg, radial_velocity=[1, 2]*u.km/u.s,
obstime='B1950')
sc2 = FK4([10, 20]*u.deg, [30, 40]*u.deg, radial_velocity=[10, 20]*u.km/u.s,
obstime='B1950')
sc1 = sc0.copy()
sc1[1] = sc2[0]
assert np.allclose(sc1.ra.to_value(u.deg), [1, 10])
assert np.allclose(sc1.dec.to_value(u.deg), [3, 30])
assert np.allclose(sc1.radial_velocity.to_value(u.km / u.s), [1, 10])
assert sc1.obstime == sc2.obstime
assert sc1.name == 'fk4'
sc1 = sc0.copy()
sc1[:] = sc2[0]
assert np.allclose(sc1.ra.to_value(u.deg), [10, 10])
assert np.allclose(sc1.dec.to_value(u.deg), [30, 30])
assert np.allclose(sc1.radial_velocity.to_value(u.km / u.s), [10, 10])
sc1 = sc0.copy()
sc1[:] = sc2[:]
assert np.allclose(sc1.ra.to_value(u.deg), [10, 20])
assert np.allclose(sc1.dec.to_value(u.deg), [30, 40])
assert np.allclose(sc1.radial_velocity.to_value(u.km / u.s), [10, 20])
sc1 = sc0.copy()
sc1[[1, 0]] = sc2[:]
assert np.allclose(sc1.ra.to_value(u.deg), [20, 10])
assert np.allclose(sc1.dec.to_value(u.deg), [40, 30])
assert np.allclose(sc1.radial_velocity.to_value(u.km / u.s), [20, 10])
def test_transform():
"""
This test just makes sure the transform architecture works, but does *not*
actually test all the builtin transforms themselves are accurate
"""
from astropy.coordinates.builtin_frames import ICRS, FK4, FK5, Galactic
from astropy.time import Time
i = ICRS(ra=[1, 2] * u.deg, dec=[3, 4] * u.deg)
f = i.transform_to(FK5)
i2 = f.transform_to(ICRS)
assert i2.data.__class__ == r.UnitSphericalRepresentation
assert_allclose(i.ra, i2.ra)
assert_allclose(i.dec, i2.dec)
i = ICRS(ra=[1, 2] * u.deg, dec=[3, 4] * u.deg, distance=[5, 6] * u.kpc)
f = i.transform_to(FK5)
i2 = f.transform_to(ICRS)
assert i2.data.__class__ != r.UnitSphericalRepresentation
f = FK5(ra=1 * u.deg, dec=2 * u.deg, equinox=Time('J2001'))
f4 = f.transform_to(FK4)
f4_2 = f.transform_to(FK4(equinox=f.equinox))
# make sure attributes are copied over correctly
assert f4.equinox == FK4.get_frame_attr_names()['equinox']
assert f4_2.equinox == f.equinox
# make sure self-transforms also work
i = ICRS(ra=[1, 2] * u.deg, dec=[3, 4] * u.deg)
i2 = i.transform_to(ICRS)
assert_allclose(i.ra, i2.ra)
assert_allclose(i.dec, i2.dec)
f = FK5(ra=1 * u.deg, dec=2 * u.deg, equinox=Time('J2001'))
f2 = f.transform_to(FK5) # default equinox, so should be *different*
assert f2.equinox == FK5().equinox
with pytest.raises(AssertionError):
assert_allclose(f.ra, f2.ra)
with pytest.raises(AssertionError):
assert_allclose(f.dec, f2.dec)
# finally, check Galactic round-tripping
i1 = ICRS(ra=[1, 2] * u.deg, dec=[3, 4] * u.deg)
i2 = i1.transform_to(Galactic).transform_to(ICRS)
assert_allclose(i1.ra, i2.ra)
assert_allclose(i1.dec, i2.dec)
def test_create_nodata_frames():
from astropy.coordinates.builtin_frames import ICRS, FK4, FK5
i = ICRS()
assert len(i.get_frame_attr_names()) == 0
f5 = FK5()
assert f5.equinox == FK5.get_frame_attr_names()['equinox']
f4 = FK4()
assert f4.equinox == FK4.get_frame_attr_names()['equinox']
# obstime is special because it's a property that uses equinox if obstime is not set
assert f4.obstime in (FK4.get_frame_attr_names()['obstime'],
FK4.get_frame_attr_names()['equinox'])
def test_create_nodata_frames():
from astropy.coordinates.builtin_frames import ICRS, FK4, FK5
i = ICRS()
assert len(i.get_frame_attr_names()) == 0
f5 = FK5()
assert f5.equinox == FK5.get_frame_attr_names()['equinox']
f4 = FK4()
assert f4.equinox == FK4.get_frame_attr_names()['equinox']
# obstime is special because it's a property that uses equinox if obstime is not set
assert f4.obstime in (FK4.get_frame_attr_names()['obstime'],
FK4.get_frame_attr_names()['equinox'])
def test_equivalent_frames():
from astropy.coordinates import SkyCoord
from astropy.coordinates.builtin_frames import ICRS, FK4, FK5, AltAz
i = ICRS()
i2 = ICRS(1 * u.deg, 2 * u.deg)
assert i.is_equivalent_frame(i)
assert i.is_equivalent_frame(i2)
with pytest.raises(TypeError):
assert i.is_equivalent_frame(10)
with pytest.raises(TypeError):
assert i2.is_equivalent_frame(SkyCoord(i2))
f0 = FK5() # this J2000 is TT
f1 = FK5(equinox='J2000')
f2 = FK5(1 * u.deg, 2 * u.deg, equinox='J2000')
f3 = FK5(equinox='J2010')
f4 = FK4(equinox='J2010')
assert f1.is_equivalent_frame(f1)
assert not i.is_equivalent_frame(f1)
assert f0.is_equivalent_frame(f1)
assert f1.is_equivalent_frame(f2)
assert not f1.is_equivalent_frame(f3)
assert not f3.is_equivalent_frame(f4)
aa1 = AltAz()
aa2 = AltAz(obstime='J2010')
assert aa2.is_equivalent_frame(aa2)
assert not aa1.is_equivalent_frame(i)
assert not aa1.is_equivalent_frame(aa2)
def test_m31_coord_transforms(fromsys, tosys, fromcoo, tocoo):
"""
This tests a variety of coordinate conversions for the Chandra point-source
catalog location of M31 from NED.
"""
coo1 = fromsys(ra=fromcoo[0] * u.deg,
dec=fromcoo[1] * u.deg,
distance=m31_dist)
coo2 = coo1.transform_to(tosys)
if tosys is FK4:
coo2_prec = coo2.transform_to(FK4(equinox=Time('B1950', scale='utc')))
assert (coo2_prec.spherical.lon -
tocoo[0] * u.deg) < convert_precision # <1 arcsec
assert (coo2_prec.spherical.lat - tocoo[1] * u.deg) < convert_precision
else:
assert (coo2.spherical.lon -
tocoo[0] * u.deg) < convert_precision # <1 arcsec
assert (coo2.spherical.lat - tocoo[1] * u.deg) < convert_precision
assert coo1.distance.unit == u.kpc
assert coo2.distance.unit == u.kpc
assert m31_dist.unit == u.kpc
assert (coo2.distance - m31_dist) < dist_precision
# check round-tripping
coo1_2 = coo2.transform_to(fromsys)
assert (coo1_2.spherical.lon - fromcoo[0] * u.deg) < roundtrip_precision
assert (coo1_2.spherical.lat - fromcoo[1] * u.deg) < roundtrip_precision
assert (coo1_2.distance - m31_dist) < dist_precision
def test_setitem_no_velocity():
"""Test different flavors of item setting for a Frame without a velocity.
"""
from astropy.coordinates.builtin_frames import FK4
obstime = 'B1955'
sc0 = FK4([1, 2]*u.deg, [3, 4]*u.deg, obstime=obstime)
sc2 = FK4([10, 20]*u.deg, [30, 40]*u.deg, obstime=obstime)
sc1 = sc0.copy()
sc1_repr = repr(sc1)
assert 'representation' in sc1.cache
sc1[1] = sc2[0]
assert sc1.cache == {}
assert repr(sc2) != sc1_repr
assert np.allclose(sc1.ra.to_value(u.deg), [1, 10])
assert np.allclose(sc1.dec.to_value(u.deg), [3, 30])
assert sc1.obstime == sc2.obstime
assert sc1.name == 'fk4'
sc1 = sc0.copy()
sc1[:] = sc2[0]
assert np.allclose(sc1.ra.to_value(u.deg), [10, 10])
assert np.allclose(sc1.dec.to_value(u.deg), [30, 30])
sc1 = sc0.copy()
sc1[:] = sc2[:]
assert np.allclose(sc1.ra.to_value(u.deg), [10, 20])
assert np.allclose(sc1.dec.to_value(u.deg), [30, 40])
sc1 = sc0.copy()
sc1[[1, 0]] = sc2[:]
assert np.allclose(sc1.ra.to_value(u.deg), [20, 10])
assert np.allclose(sc1.dec.to_value(u.deg), [40, 30])
# Works for array-valued obstime so long as they are considered equivalent
sc1 = FK4(sc0.ra, sc0.dec, obstime=[obstime, obstime])
sc1[0] = sc2[0]
# Multidimensional coordinates
sc1 = FK4([[1, 2], [3, 4]] * u.deg, [[5, 6], [7, 8]] * u.deg)
sc2 = FK4([[10, 20], [30, 40]] * u.deg, [[50, 60], [70, 80]] * u.deg)
sc1[0] = sc2[0]
assert np.allclose(sc1.ra.to_value(u.deg), [[10, 20], [3, 4]])
assert np.allclose(sc1.dec.to_value(u.deg), [[50, 60], [7, 8]])
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_precession():
"""
Ensures that FK4 and FK5 coordinates precess their equinoxes
"""
j2000 = Time('J2000')
b1950 = Time('B1950')
j1975 = Time('J1975')
b1975 = Time('B1975')
fk4 = FK4(ra=1*u.radian, dec=0.5*u.radian)
assert fk4.equinox.byear == b1950.byear
fk4_2 = fk4.transform_to(FK4(equinox=b1975))
assert fk4_2.equinox.byear == b1975.byear
fk5 = FK5(ra=1*u.radian, dec=0.5*u.radian)
assert fk5.equinox.jyear == j2000.jyear
fk5_2 = fk5.transform_to(FK4(equinox=j1975))
assert fk5_2.equinox.jyear == j1975.jyear
def test_obstime():
"""
Checks to make sure observation time is
accounted for at least in FK4 <-> ICRS transformations
"""
b1950 = Time('B1950')
j1975 = Time('J1975')
fk4_50 = FK4(ra=1*u.deg, dec=2*u.deg, obstime=b1950)
fk4_75 = FK4(ra=1*u.deg, dec=2*u.deg, obstime=j1975)
icrs_50 = fk4_50.transform_to(ICRS())
icrs_75 = fk4_75.transform_to(ICRS())
# now check that the resulting coordinates are *different* - they should be,
# because the obstime is different
assert icrs_50.ra.degree != icrs_75.ra.degree
assert icrs_50.dec.degree != icrs_75.dec.degree
def test_fk4_no_e_fk4():
lines = get_pkg_data_contents('data/fk4_no_e_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
# FK4 to FK4NoETerms
c1 = FK4(ra=r['ra_in'] * u.deg,
dec=r['dec_in'] * u.deg,
obstime=Time(r['obstime']))
c2 = c1.transform_to(FK4NoETerms())
# Find difference
diff = angular_separation(c2.ra.radian, c2.dec.radian,
np.radians(r['ra_fk4ne']),
np.radians(r['dec_fk4ne']))
diffarcsec1.append(np.degrees(diff) * 3600.)
# FK4NoETerms to FK4
c1 = FK4NoETerms(ra=r['ra_in'] * u.deg,
dec=r['dec_in'] * u.deg,
obstime=Time(r['obstime']))
c2 = c1.transform_to(FK4())
# Find difference
diff = angular_separation(c2.ra.radian, c2.dec.radian,
np.radians(r['ra_fk4']),
np.radians(r['dec_fk4']))
diffarcsec2.append(np.degrees(diff) * 3600.)
np.testing.assert_array_less(diffarcsec1, TOLERANCE)
np.testing.assert_array_less(diffarcsec2, TOLERANCE)
def test_transform():
"""
This test just makes sure the transform architecture works, but does *not*
actually test all the builtin transforms themselves are accurate
"""
from astropy.coordinates.builtin_frames import ICRS, FK4, FK5, Galactic
from astropy.time import Time
i = ICRS(ra=[1, 2]*u.deg, dec=[3, 4]*u.deg)
f = i.transform_to(FK5)
i2 = f.transform_to(ICRS)
assert i2.data.__class__ == r.UnitSphericalRepresentation
assert_allclose(i.ra, i2.ra)
assert_allclose(i.dec, i2.dec)
i = ICRS(ra=[1, 2]*u.deg, dec=[3, 4]*u.deg, distance=[5, 6]*u.kpc)
f = i.transform_to(FK5)
i2 = f.transform_to(ICRS)
assert i2.data.__class__ != r.UnitSphericalRepresentation
f = FK5(ra=1*u.deg, dec=2*u.deg, equinox=Time('J2001'))
f4 = f.transform_to(FK4)
f4_2 = f.transform_to(FK4(equinox=f.equinox))
# make sure attributes are copied over correctly
assert f4.equinox == FK4.get_frame_attr_names()['equinox']
assert f4_2.equinox == f.equinox
# make sure self-transforms also work
i = ICRS(ra=[1, 2]*u.deg, dec=[3, 4]*u.deg)
i2 = i.transform_to(ICRS)
assert_allclose(i.ra, i2.ra)
assert_allclose(i.dec, i2.dec)
f = FK5(ra=1*u.deg, dec=2*u.deg, equinox=Time('J2001'))
f2 = f.transform_to(FK5) # default equinox, so should be *different*
assert f2.equinox == FK5().equinox
with pytest.raises(AssertionError):
assert_allclose(f.ra, f2.ra)
with pytest.raises(AssertionError):
assert_allclose(f.dec, f2.dec)
# finally, check Galactic round-tripping
i1 = ICRS(ra=[1, 2]*u.deg, dec=[3, 4]*u.deg)
i2 = i1.transform_to(Galactic).transform_to(ICRS)
assert_allclose(i1.ra, i2.ra)
assert_allclose(i1.dec, i2.dec)
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_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
