def test_icrs_hadec_consistency():
"""
Check ICRS<->HADec for consistency with ICRS<->CIRS<->HADec
"""
usph = golden_spiral_grid(200)
dist = np.linspace(0.5, 1, len(usph)) * u.km * 1e5
icoo = SkyCoord(ra=usph.lon, dec=usph.lat, distance=dist)
observer = EarthLocation(28*u.deg, 23*u.deg, height=2000.*u.km)
obstime = Time('J2010')
hd_frame = HADec(obstime=obstime, location=observer)
# check we are going direct!
trans = frame_transform_graph.get_transform(ICRS, HADec).transforms
assert(len(trans) == 1)
# check that ICRS-HADec and ICRS->CIRS->HADec are consistent
aa1 = icoo.transform_to(hd_frame)
aa2 = icoo.transform_to(CIRS()).transform_to(hd_frame)
assert_allclose(aa1.separation_3d(aa2), 0*u.mm, atol=1*u.mm)
# check roundtrip
roundtrip = icoo.transform_to(hd_frame).transform_to(icoo)
assert_allclose(roundtrip.separation_3d(icoo), 0*u.mm, atol=1*u.mm)
# check there and back via CIRS mish-mash
roundtrip = icoo.transform_to(hd_frame).transform_to(
CIRS()).transform_to(icoo)
assert_allclose(roundtrip.separation_3d(icoo), 0*u.mm, atol=1*u.mm)
def test_regression_futuretimes_4302():
"""
Checks that an error is not raised for future times not covered by IERS
tables (at least in a simple transform like CIRS->ITRS that simply requires
the UTC<->UT1 conversion).
Relevant comment: https://github.com/astropy/astropy/pull/4302#discussion_r44836531
"""
from astropy.utils.exceptions import AstropyWarning
# this is an ugly hack to get the warning to show up even if it has already
# appeared
from astropy.coordinates.builtin_frames import utils
if hasattr(utils, '__warningregistry__'):
utils.__warningregistry__.clear()
with catch_warnings() as found_warnings:
future_time = Time('2511-5-1')
c = CIRS(1*u.deg, 2*u.deg, obstime=future_time)
c.transform_to(ITRS(obstime=future_time))
if not isinstance(iers.IERS_Auto.iers_table, iers.IERS_Auto):
saw_iers_warnings = False
for w in found_warnings:
if issubclass(w.category, AstropyWarning):
if '(some) times are outside of range covered by IERS table' in str(w.message):
saw_iers_warnings = True
break
assert saw_iers_warnings, 'Never saw IERS warning'
def test_regression_futuretimes_4302():
"""
Checks that an error is not raised for future times not covered by IERS
tables (at least in a simple transform like CIRS->ITRS that simply requires
the UTC<->UT1 conversion).
Relevant comment: https://github.com/astropy/astropy/pull/4302#discussion_r44836531
"""
from astropy.utils.exceptions import AstropyWarning
# this is an ugly hack to get the warning to show up even if it has already
# appeared
from astropy.coordinates.builtin_frames import utils
if hasattr(utils, '__warningregistry__'):
utils.__warningregistry__.clear()
with catch_warnings() as found_warnings:
future_time = Time('2511-5-1')
c = CIRS(1 * u.deg, 2 * u.deg, obstime=future_time)
c.transform_to(ITRS(obstime=future_time))
if not isinstance(iers.IERS_Auto.iers_table, iers.IERS_Auto):
saw_iers_warnings = False
for w in found_warnings:
if issubclass(w.category, AstropyWarning):
if '(some) times are outside of range covered by IERS table' in str(
w.message):
saw_iers_warnings = True
break
assert saw_iers_warnings, 'Never saw IERS warning'
def test_straight_overhead():
"""
With a precise CIRS<->AltAz transformation this should give Alt=90 exactly
If the CIRS self-transform breaks it won't, due to improper treatment of aberration
"""
t = Time('J2010')
obj = EarthLocation(-1 * u.deg, 52 * u.deg, height=10. * u.km)
home = EarthLocation(-1 * u.deg, 52 * u.deg, height=0. * u.km)
# An object that appears straight overhead - FOR A GEOCENTRIC OBSERVER.
# Note, this won't be overhead for a topocentric observer because of
# aberration.
cirs_geo = obj.get_itrs(t).transform_to(CIRS(obstime=t))
# now get the Geocentric CIRS position of observatory
obsrepr = home.get_itrs(t).transform_to(CIRS(obstime=t)).cartesian
# topocentric CIRS position of a straight overhead object
cirs_repr = cirs_geo.cartesian - obsrepr
# create a CIRS object that appears straight overhead for a TOPOCENTRIC OBSERVER
topocentric_cirs_frame = CIRS(obstime=t, location=home)
cirs_topo = topocentric_cirs_frame.realize_frame(cirs_repr)
# Check AltAz (though Azimuth can be anything so is not tested).
aa = cirs_topo.transform_to(AltAz(obstime=t, location=home))
assert_allclose(aa.alt, 90 * u.deg, atol=1 * u.uas, rtol=0)
# Check HADec.
hd = cirs_topo.transform_to(HADec(obstime=t, location=home))
assert_allclose(hd.ha, 0 * u.hourangle, atol=1 * u.uas, rtol=0)
assert_allclose(hd.dec, 52 * u.deg, atol=1 * u.uas, rtol=0)
def test_regression_futuretimes_4302():
"""
Checks that an error is not raised for future times not covered by IERS
tables (at least in a simple transform like CIRS->ITRS that simply requires
the UTC<->UT1 conversion).
Relevant comment: https://github.com/astropy/astropy/pull/4302#discussion_r44836531
"""
from astropy.utils.compat.context import nullcontext
from astropy.utils.exceptions import AstropyWarning
# this is an ugly hack to get the warning to show up even if it has already
# appeared
from astropy.coordinates.builtin_frames import utils
if hasattr(utils, '__warningregistry__'):
utils.__warningregistry__.clear()
# check that out-of-range warning appears among any other warnings. If
# tests are run with --remote-data then the IERS table will be an instance
# of IERS_Auto which is assured of being "fresh". In this case getting
# times outside the range of the table does not raise an exception. Only
# if using IERS_B (which happens without --remote-data, i.e. for all CI
# testing) do we expect another warning.
if isinstance(iers.earth_orientation_table.get(), iers.IERS_B):
ctx = pytest.warns(
AstropyWarning,
match=r'\(some\) times are outside of range covered by IERS table.*')
else:
ctx = nullcontext()
with ctx:
future_time = Time('2511-5-1')
c = CIRS(1*u.deg, 2*u.deg, obstime=future_time)
c.transform_to(ITRS(obstime=future_time))
def test_gcrs_cirs():
"""
Check GCRS<->CIRS transforms for round-tripping. More complicated than the
above two because it's multi-hop
"""
usph = golden_spiral_grid(200)
gcrs = GCRS(usph, obstime='J2000')
gcrs6 = GCRS(usph, obstime='J2006')
gcrs2 = gcrs.transform_to(CIRS()).transform_to(gcrs)
gcrs6_2 = gcrs6.transform_to(CIRS()).transform_to(gcrs)
assert_allclose(gcrs.ra, gcrs2.ra)
assert_allclose(gcrs.dec, gcrs2.dec)
# these should be different:
assert not allclose(gcrs.ra, gcrs6_2.ra, rtol=1e-8)
assert not allclose(gcrs.dec, gcrs6_2.dec, rtol=1e-8)
# now try explicit intermediate pathways and ensure they're all consistent
gcrs3 = gcrs.transform_to(ITRS()).transform_to(CIRS()).transform_to(
ITRS()).transform_to(gcrs)
assert_allclose(gcrs.ra, gcrs3.ra)
assert_allclose(gcrs.dec, gcrs3.dec)
gcrs4 = gcrs.transform_to(ICRS()).transform_to(CIRS()).transform_to(
ICRS()).transform_to(gcrs)
assert_allclose(gcrs.ra, gcrs4.ra)
assert_allclose(gcrs.dec, gcrs4.dec)
def test_gcrs_cirs():
"""
Check GCRS<->CIRS transforms for round-tripping. More complicated than the
above two because it's multi-hop
"""
ra, dec, _ = randomly_sample_sphere(200)
gcrs = GCRS(ra=ra, dec=dec, obstime='J2000')
gcrs6 = GCRS(ra=ra, dec=dec, obstime='J2006')
gcrs2 = gcrs.transform_to(CIRS()).transform_to(gcrs)
gcrs6_2 = gcrs6.transform_to(CIRS()).transform_to(gcrs)
assert_allclose(gcrs.ra, gcrs2.ra)
assert_allclose(gcrs.dec, gcrs2.dec)
assert not allclose(gcrs.ra, gcrs6_2.ra)
assert not allclose(gcrs.dec, gcrs6_2.dec)
# now try explicit intermediate pathways and ensure they're all consistent
gcrs3 = gcrs.transform_to(ITRS()).transform_to(CIRS()).transform_to(
ITRS()).transform_to(gcrs)
assert_allclose(gcrs.ra, gcrs3.ra)
assert_allclose(gcrs.dec, gcrs3.dec)
gcrs4 = gcrs.transform_to(ICRS()).transform_to(CIRS()).transform_to(
ICRS()).transform_to(gcrs)
assert_allclose(gcrs.ra, gcrs4.ra)
assert_allclose(gcrs.dec, gcrs4.dec)
def test_gcrs_altaz():
"""
Check GCRS<->AltAz transforms for round-tripping. Has multiple paths
"""
from astropy.coordinates import EarthLocation
usph = golden_spiral_grid(128)
gcrs = GCRS(usph, obstime='J2000')[None] # broadcast with times below
# check array times sure N-d arrays work
times = Time(np.linspace(2456293.25, 2456657.25, 51) * u.day,
format='jd')[:, None]
loc = EarthLocation(lon=10 * u.deg, lat=80. * u.deg)
aaframe = AltAz(obstime=times, location=loc)
aa1 = gcrs.transform_to(aaframe)
aa2 = gcrs.transform_to(ICRS()).transform_to(CIRS()).transform_to(aaframe)
aa3 = gcrs.transform_to(ITRS()).transform_to(CIRS()).transform_to(aaframe)
# make sure they're all consistent
assert_allclose(aa1.alt, aa2.alt)
assert_allclose(aa1.az, aa2.az)
assert_allclose(aa1.alt, aa3.alt)
assert_allclose(aa1.az, aa3.az)
def test_gcrs_altaz():
"""
Check GCRS<->AltAz transforms for round-tripping. Has multiple paths
"""
from astropy.coordinates import EarthLocation
ra, dec, _ = randomly_sample_sphere(1)
gcrs = GCRS(ra=ra[0], dec=dec[0], obstime='J2000')
# check array times sure N-d arrays work
times = Time(np.linspace(2456293.25, 2456657.25, 51) * u.day,
format='jd')
loc = EarthLocation(lon=10 * u.deg, lat=80. * u.deg)
aaframe = AltAz(obstime=times, location=loc)
aa1 = gcrs.transform_to(aaframe)
aa2 = gcrs.transform_to(ICRS()).transform_to(CIRS()).transform_to(aaframe)
aa3 = gcrs.transform_to(ITRS()).transform_to(CIRS()).transform_to(aaframe)
# make sure they're all consistent
assert_allclose(aa1.alt, aa2.alt)
assert_allclose(aa1.az, aa2.az)
assert_allclose(aa1.alt, aa3.alt)
assert_allclose(aa1.az, aa3.az)
def test_gcrs_hadec():
"""
Check GCRS<->HADec transforms for round-tripping. Has multiple paths
"""
from astropy.coordinates import EarthLocation
usph = golden_spiral_grid(128)
gcrs = GCRS(usph, obstime='J2000') # broadcast with times below
# check array times sure N-d arrays work
times = Time(np.linspace(2456293.25, 2456657.25, 51) * u.day,
format='jd')[:, np.newaxis]
loc = EarthLocation(lon=10 * u.deg, lat=80. * u.deg)
hdframe = HADec(obstime=times, location=loc)
hd1 = gcrs.transform_to(hdframe)
hd2 = gcrs.transform_to(ICRS()).transform_to(CIRS()).transform_to(hdframe)
hd3 = gcrs.transform_to(ITRS()).transform_to(CIRS()).transform_to(hdframe)
# make sure they're all consistent
assert_allclose(hd1.dec, hd2.dec)
assert_allclose(hd1.ha, hd2.ha)
assert_allclose(hd1.dec, hd3.dec)
assert_allclose(hd1.ha, hd3.ha)
def test_icrs_consistency():
"""
Check ICRS<->AltAz for consistency with ICRS<->CIRS<->AltAz
The latter is extensively tested in test_intermediate_transformations.py
"""
ra, dec, dist = randomly_sample_sphere(200)
icoo = SkyCoord(ra=ra, dec=dec, distance=dist * u.km * 1e5)
observer = EarthLocation(28 * u.deg, 23 * u.deg, height=2000. * u.km)
obstime = Time('J2010')
aa_frame = AltAz(obstime=obstime, location=observer)
# check we are going direct!
trans = frame_transform_graph.get_transform(ICRS, AltAz).transforms
assert (len(trans) == 1)
# check that ICRS-AltAz and ICRS->CIRS->AltAz are consistent
aa1 = icoo.transform_to(aa_frame)
aa2 = icoo.transform_to(CIRS()).transform_to(aa_frame)
assert_allclose(aa1.separation_3d(aa2), 0 * u.mm, atol=1 * u.mm)
# check roundtrip
roundtrip = icoo.transform_to(aa_frame).transform_to(icoo)
assert_allclose(roundtrip.separation_3d(icoo), 0 * u.mm, atol=1 * u.mm)
# check there and back via CIRS mish-mash
roundtrip = icoo.transform_to(aa_frame).transform_to(
CIRS()).transform_to(icoo)
assert_allclose(roundtrip.separation_3d(icoo), 0 * u.mm, atol=1 * u.mm)
def test_cirs_icrs_moonish(testframe):
"""
check that something like the moon goes to about the right distance from the
ICRS origin when starting from CIRS
"""
moonish = CIRS(MOONDIST_CART, obstime=testframe.obstime)
moonicrs = moonish.transform_to(ICRS)
assert 0.97*u.au < moonicrs.distance < 1.03*u.au
def test_cirs_icrs_moonish(testframe):
"""
check that something like the moon goes to about the right distance from the
ICRS origin when starting from CIRS
"""
moonish = CIRS(MOONDIST_CART, obstime=testframe.obstime)
moonicrs = moonish.transform_to(ICRS())
assert 0.97 * u.au < moonicrs.distance < 1.03 * u.au
def test_cirs_altaz_nodist(testframe):
"""
Check that a UnitSphericalRepresentation coordinate round-trips for the
CIRS<->AltAz transformation.
"""
coo0 = CIRS(UnitSphericalRepresentation(10*u.deg, 20*u.deg), obstime=testframe.obstime)
# check that it round-trips
coo1 = coo0.transform_to(testframe).transform_to(coo0)
assert_allclose(coo0.cartesian.xyz, coo1.cartesian.xyz)
def test_cirs_altaz_nodist(testframe):
"""
Check that a UnitSphericalRepresentation coordinate round-trips for the
CIRS<->AltAz transformation.
"""
coo0 = CIRS(UnitSphericalRepresentation(10*u.deg, 20*u.deg), obstime=testframe.obstime)
# check that it round-trips
coo1 = coo0.transform_to(testframe).transform_to(coo0)
assert_allclose(coo0.cartesian.xyz, coo1.cartesian.xyz)
def test_cirs_altaz_moonish(testframe):
"""
Sanity-check that an object resembling the moon goes to the right place with
a CIRS<->AltAz transformation
"""
moon = CIRS(MOONDIST_CART, obstime=testframe.obstime)
moonaa = moon.transform_to(testframe)
assert 1000*u.km < np.abs(moonaa.distance - moon.distance).to(u.km) < 7000*u.km
# now check that it round-trips
moon2 = moonaa.transform_to(moon)
assert_allclose(moon.cartesian.xyz, moon2.cartesian.xyz)
def test_cirs_altaz_moonish(testframe):
"""
Sanity-check that an object resembling the moon goes to the right place with
a CIRS<->AltAz transformation
"""
moon = CIRS(MOONDIST_CART, obstime=testframe.obstime)
moonaa = moon.transform_to(testframe)
assert 1000*u.km < np.abs(moonaa.distance - moon.distance).to(u.km) < 7000*u.km
# now check that it round-trips
moon2 = moonaa.transform_to(moon)
assert_allclose(moon.cartesian.xyz, moon2.cartesian.xyz)
def test_interpolation_nd():
'''
Test that the interpolation also works for nd-arrays
'''
fact = EarthLocation(
lon=-17.891105 * u.deg,
lat=28.761584 * u.deg,
height=2200 * u.m,
)
interp_provider = ErfaAstromInterpolator(300 * u.s)
provider = ErfaAstrom()
for shape in [tuple(), (1, ), (10, ), (3, 2), (2, 10, 5), (4, 5, 3, 2)]:
# create obstimes of the desired shapes
delta_t = np.linspace(0, 12, np.prod(shape, dtype=int)) * u.hour
obstime = (Time('2020-01-01T18:00') + delta_t).reshape(shape)
altaz = AltAz(location=fact, obstime=obstime)
gcrs = GCRS(obstime=obstime)
cirs = CIRS(obstime=obstime)
for frame, tcode in zip([altaz, cirs, gcrs], ['apio', 'apco', 'apcs']):
without_interp = getattr(provider, tcode)(frame)
assert without_interp.shape == shape
with_interp = getattr(interp_provider, tcode)(frame)
assert with_interp.shape == shape
def test_cirs_itrs():
"""
Check basic CIRS<->ITRS transforms for round-tripping.
"""
ra, dec, _ = randomly_sample_sphere(200)
cirs = CIRS(ra=ra, dec=dec, obstime='J2000')
cirs6 = CIRS(ra=ra, dec=dec, obstime='J2006')
cirs2 = cirs.transform_to(ITRS).transform_to(cirs)
cirs6_2 = cirs6.transform_to(ITRS).transform_to(cirs) # different obstime
# just check round-tripping
assert_allclose(cirs.ra, cirs2.ra)
assert_allclose(cirs.dec, cirs2.dec)
assert not allclose(cirs.ra, cirs6_2.ra)
assert not allclose(cirs.dec, cirs6_2.dec)
def _calc_parallactic_angles(times, observing_location, phase_center):
"""
Computes parallactic angles per timestep for the given
reference antenna position and field centre.
Based on https://github.com/ska-sa/codex-africanus/blob/068c14fb6cf0c6802117689042de5f55dc49d07c/africanus/rime/parangles_astropy.py
"""
from astropy.coordinates import (EarthLocation, SkyCoord, AltAz, CIRS)
from astropy.time import Time
from astropy import units
import numpy as np
pole = SkyCoord(ra=0, dec=90, unit=units.deg, frame='fk5')
cirs_frame = CIRS(obstime=times)
pole_cirs = pole.transform_to(cirs_frame)
phase_center_cirs = phase_center.transform_to(cirs_frame)
altaz_frame = AltAz(location=observing_location, obstime=times)
pole_altaz = pole_cirs.transform_to(altaz_frame)
phase_center_altaz = phase_center_cirs.transform_to(altaz_frame)
#print('the zen angle is',phase_center_altaz.zen)
#print('the zen angle is',pole_altaz.zen)
return phase_center_altaz.position_angle(pole_altaz).value
def test_cirs_quick(self):
cirs_frame = CIRS(location=self.loc, obstime=self.obstime)
# Following copied from intermediate_rotation_transforms.gcrs_to_cirs
pmat = gcrs_to_cirs_mat(cirs_frame.obstime)
loc_gcrs_frame = get_location_gcrs(
self.loc, self.obstime, cirs_to_itrs_mat(cirs_frame.obstime), pmat)
self.check_obsgeo(loc_gcrs_frame.obsgeoloc, loc_gcrs_frame.obsgeovel)
def astropy_parallactic_angles(times, antenna_positions, field_centre):
"""
Computes parallactic angles per timestep for the given
reference antenna position and field centre.
"""
ap = antenna_positions
fc = field_centre
# Convert from MJD second to MJD
times = Time(times / 86400.00, format='mjd', scale='utc')
ap = EarthLocation.from_geocentric(ap[:, 0],
ap[:, 1],
ap[:, 2],
unit='m')
fc = SkyCoord(ra=fc[0], dec=fc[1], unit=units.rad, frame='fk5')
pole = SkyCoord(ra=0, dec=90, unit=units.deg, frame='fk5')
cirs_frame = CIRS(obstime=times)
pole_cirs = pole.transform_to(cirs_frame)
fc_cirs = fc.transform_to(cirs_frame)
altaz_frame = AltAz(location=ap[None, :], obstime=times[:, None])
pole_altaz = pole_cirs[:, None].transform_to(altaz_frame)
fc_altaz = fc_cirs[:, None].transform_to(altaz_frame)
return fc_altaz.position_angle(pole_altaz)
def test_icrs_cirs():
"""
Check a few cases of ICRS<->CIRS for consistency.
Also includes the CIRS<->CIRS transforms at different times, as those go
through ICRS
"""
usph = golden_spiral_grid(200)
dist = np.linspace(0., 1, len(usph)) * u.pc
inod = ICRS(usph)
iwd = ICRS(ra=usph.lon, dec=usph.lat, distance=dist)
cframe1 = CIRS()
cirsnod = inod.transform_to(cframe1) # uses the default time
# first do a round-tripping test
inod2 = cirsnod.transform_to(ICRS())
assert_allclose(inod.ra, inod2.ra)
assert_allclose(inod.dec, inod2.dec)
# now check that a different time yields different answers
cframe2 = CIRS(obstime=Time('J2005'))
cirsnod2 = inod.transform_to(cframe2)
assert not allclose(cirsnod.ra, cirsnod2.ra, rtol=1e-8)
assert not allclose(cirsnod.dec, cirsnod2.dec, rtol=1e-8)
# parallax effects should be included, so with and w/o distance should be different
cirswd = iwd.transform_to(cframe1)
assert not allclose(cirswd.ra, cirsnod.ra, rtol=1e-8)
assert not allclose(cirswd.dec, cirsnod.dec, rtol=1e-8)
# and the distance should transform at least somehow
assert not allclose(cirswd.distance, iwd.distance, rtol=1e-8)
# now check that the cirs self-transform works as expected
cirsnod3 = cirsnod.transform_to(cframe1) # should be a no-op
assert_allclose(cirsnod.ra, cirsnod3.ra)
assert_allclose(cirsnod.dec, cirsnod3.dec)
cirsnod4 = cirsnod.transform_to(cframe2) # should be different
assert not allclose(cirsnod4.ra, cirsnod.ra, rtol=1e-8)
assert not allclose(cirsnod4.dec, cirsnod.dec, rtol=1e-8)
cirsnod5 = cirsnod4.transform_to(cframe1) # should be back to the same
assert_allclose(cirsnod.ra, cirsnod5.ra)
assert_allclose(cirsnod.dec, cirsnod5.dec)
def test_icrs_cirs():
"""
Check a few cases of ICRS<->CIRS for consistency.
Also includes the CIRS<->CIRS transforms at different times, as those go
through ICRS
"""
ra, dec, dist = randomly_sample_sphere(200)
inod = ICRS(ra=ra, dec=dec)
iwd = ICRS(ra=ra, dec=dec, distance=dist * u.pc)
cframe1 = CIRS()
cirsnod = inod.transform_to(cframe1) # uses the default time
# first do a round-tripping test
inod2 = cirsnod.transform_to(ICRS)
assert_allclose(inod.ra, inod2.ra)
assert_allclose(inod.dec, inod2.dec)
# now check that a different time yields different answers
cframe2 = CIRS(obstime=Time('J2005', scale='utc'))
cirsnod2 = inod.transform_to(cframe2)
assert not allclose(cirsnod.ra, cirsnod2.ra, rtol=1e-8)
assert not allclose(cirsnod.dec, cirsnod2.dec, rtol=1e-8)
# parallax effects should be included, so with and w/o distance should be different
cirswd = iwd.transform_to(cframe1)
assert not allclose(cirswd.ra, cirsnod.ra, rtol=1e-8)
assert not allclose(cirswd.dec, cirsnod.dec, rtol=1e-8)
# and the distance should transform at least somehow
assert not allclose(cirswd.distance, iwd.distance, rtol=1e-8)
# now check that the cirs self-transform works as expected
cirsnod3 = cirsnod.transform_to(cframe1) # should be a no-op
assert_allclose(cirsnod.ra, cirsnod3.ra)
assert_allclose(cirsnod.dec, cirsnod3.dec)
cirsnod4 = cirsnod.transform_to(cframe2) # should be different
assert not allclose(cirsnod4.ra, cirsnod.ra, rtol=1e-8)
assert not allclose(cirsnod4.dec, cirsnod.dec, rtol=1e-8)
cirsnod5 = cirsnod4.transform_to(cframe1) # should be back to the same
assert_allclose(cirsnod.ra, cirsnod5.ra)
assert_allclose(cirsnod.dec, cirsnod5.dec)
def test_tete_transforms():
"""
We test the TETE transforms for proper behaviour here.
The TETE transforms are tested for accuracy against JPL Horizons in
test_solar_system.py. Here we are looking to check for consistency and
errors in the self transform.
"""
loc = EarthLocation.from_geodetic("-22°57'35.1", "-67°47'14.1", 5186 * u.m)
time = Time('2020-04-06T00:00')
p, v = loc.get_gcrs_posvel(time)
gcrs_frame = GCRS(obstime=time, obsgeoloc=p, obsgeovel=v)
moon = SkyCoord(169.24113968 * u.deg,
10.86086666 * u.deg,
358549.25381755 * u.km,
frame=gcrs_frame)
tete_frame = TETE(obstime=time, location=loc)
# need to set obsgeoloc/vel explicity or skycoord behaviour over-writes
tete_geo = TETE(obstime=time, location=EarthLocation(*([0, 0, 0] * u.km)))
# test self-transform by comparing to GCRS-TETE-ITRS-TETE route
tete_coo1 = moon.transform_to(tete_frame)
tete_coo2 = moon.transform_to(tete_geo)
assert_allclose(tete_coo1.separation_3d(tete_coo2),
0 * u.mm,
atol=1 * u.mm)
# test TETE-ITRS transform by comparing GCRS-CIRS-ITRS to GCRS-TETE-ITRS
itrs1 = moon.transform_to(CIRS()).transform_to(ITRS())
itrs2 = moon.transform_to(TETE()).transform_to(ITRS())
# this won't be as close since it will round trip through ICRS until
# we have some way of translating between the GCRS obsgeoloc/obsgeovel
# attributes and the CIRS location attributes
assert_allclose(itrs1.separation_3d(itrs2), 0 * u.mm, atol=100 * u.mm)
# test round trip GCRS->TETE->GCRS
new_moon = moon.transform_to(TETE()).transform_to(moon)
assert_allclose(new_moon.separation_3d(moon), 0 * u.mm, atol=1 * u.mm)
# test round trip via ITRS
tete_rt = tete_coo1.transform_to(
ITRS(obstime=time)).transform_to(tete_coo1)
assert_allclose(tete_rt.separation_3d(tete_coo1), 0 * u.mm, atol=1 * u.mm)
# ensure deprecated routine remains consistent
# make sure test raises warning!
with pytest.warns(AstropyDeprecationWarning, match='The use of'):
tete_alt = _apparent_position_in_true_coordinates(moon)
assert_allclose(tete_coo1.separation_3d(tete_alt),
0 * u.mm,
atol=100 * u.mm)
def test_cirs_to_hadec():
"""
Check the basic CIRS<->HADec transforms.
"""
from astropy.coordinates import EarthLocation
usph = golden_spiral_grid(200)
dist = np.linspace(0.5, 1, len(usph)) * u.pc
cirs = CIRS(usph, obstime='J2000')
crepr = SphericalRepresentation(lon=usph.lon, lat=usph.lat, distance=dist)
cirscart = CIRS(crepr,
obstime=cirs.obstime,
representation_type=CartesianRepresentation)
loc = EarthLocation(lat=0 * u.deg, lon=0 * u.deg, height=0 * u.m)
hadecframe = HADec(location=loc, obstime=Time('J2005'))
cirs2 = cirs.transform_to(hadecframe).transform_to(cirs)
cirs3 = cirscart.transform_to(hadecframe).transform_to(cirs)
# check round-tripping
assert_allclose(cirs.ra, cirs2.ra)
assert_allclose(cirs.dec, cirs2.dec)
assert_allclose(cirs.ra, cirs3.ra)
assert_allclose(cirs.dec, cirs3.dec)
def test_cirs_to_altaz():
"""
Check the basic CIRS<->AltAz transforms. More thorough checks implicitly
happen in `test_iau_fullstack`
"""
from astropy.coordinates import EarthLocation
ra, dec, dist = randomly_sample_sphere(200)
cirs = CIRS(ra=ra, dec=dec, obstime='J2000')
crepr = SphericalRepresentation(lon=ra, lat=dec, distance=dist)
cirscart = CIRS(crepr,
obstime=cirs.obstime,
representation_type=CartesianRepresentation)
loc = EarthLocation(lat=0 * u.deg, lon=0 * u.deg, height=0 * u.m)
altazframe = AltAz(location=loc, obstime=Time('J2005'))
cirs2 = cirs.transform_to(altazframe).transform_to(cirs)
cirs3 = cirscart.transform_to(altazframe).transform_to(cirs)
# check round-tripping
assert_allclose(cirs.ra, cirs2.ra)
assert_allclose(cirs.dec, cirs2.dec)
assert_allclose(cirs.ra, cirs3.ra)
assert_allclose(cirs.dec, cirs3.dec)
def test_cirs_to_altaz():
"""
Check the basic CIRS<->AltAz transforms. More thorough checks implicitly
happen in `test_iau_fullstack`
"""
from astropy.coordinates import EarthLocation
ra, dec, dist = randomly_sample_sphere(200)
cirs = CIRS(ra=ra, dec=dec, obstime='J2000')
crepr = SphericalRepresentation(lon=ra, lat=dec, distance=dist)
cirscart = CIRS(crepr, obstime=cirs.obstime, representation_type=CartesianRepresentation)
loc = EarthLocation(lat=0*u.deg, lon=0*u.deg, height=0*u.m)
altazframe = AltAz(location=loc, obstime=Time('J2005'))
cirs2 = cirs.transform_to(altazframe).transform_to(cirs)
cirs3 = cirscart.transform_to(altazframe).transform_to(cirs)
# check round-tripping
assert_allclose(cirs.ra, cirs2.ra)
assert_allclose(cirs.dec, cirs2.dec)
assert_allclose(cirs.ra, cirs3.ra)
assert_allclose(cirs.dec, cirs3.dec)
def test_icrs_gcrscirs_sunish(testframe):
"""
check that the ICRS barycenter goes to about the right distance from various
~geocentric frames (other than testframe)
"""
# slight offset to avoid divide-by-zero errors
icrs = ICRS(0*u.deg, 0*u.deg, distance=10*u.km)
gcrs = icrs.transform_to(GCRS(obstime=testframe.obstime))
assert (EARTHECC - 1)*u.au < gcrs.distance.to(u.au) < (EARTHECC + 1)*u.au
cirs = icrs.transform_to(CIRS(obstime=testframe.obstime))
assert (EARTHECC - 1)*u.au < cirs.distance.to(u.au) < (EARTHECC + 1)*u.au
itrs = icrs.transform_to(ITRS(obstime=testframe.obstime))
assert (EARTHECC - 1)*u.au < itrs.spherical.distance.to(u.au) < (EARTHECC + 1)*u.au
def test_ephemerides():
"""
We test that using different ephemerides gives very similar results
for transformations
"""
t = Time("2014-12-25T07:00")
moon = SkyCoord(
GCRS(318.10579159 * u.deg,
-11.65281165 * u.deg,
365042.64880308 * u.km,
obstime=t))
icrs_frame = ICRS()
hcrs_frame = HCRS(obstime=t)
ecl_frame = HeliocentricMeanEcliptic(equinox=t)
cirs_frame = CIRS(obstime=t)
moon_icrs_builtin = moon.transform_to(icrs_frame)
moon_hcrs_builtin = moon.transform_to(hcrs_frame)
moon_helioecl_builtin = moon.transform_to(ecl_frame)
moon_cirs_builtin = moon.transform_to(cirs_frame)
with solar_system_ephemeris.set('jpl'):
moon_icrs_jpl = moon.transform_to(icrs_frame)
moon_hcrs_jpl = moon.transform_to(hcrs_frame)
moon_helioecl_jpl = moon.transform_to(ecl_frame)
moon_cirs_jpl = moon.transform_to(cirs_frame)
# most transformations should differ by an amount which is
# non-zero but of order milliarcsecs
sep_icrs = moon_icrs_builtin.separation(moon_icrs_jpl)
sep_hcrs = moon_hcrs_builtin.separation(moon_hcrs_jpl)
sep_helioecl = moon_helioecl_builtin.separation(moon_helioecl_jpl)
sep_cirs = moon_cirs_builtin.separation(moon_cirs_jpl)
assert_allclose([sep_icrs, sep_hcrs, sep_helioecl],
0.0 * u.deg,
atol=10 * u.mas)
assert all(sep > 10 * u.microarcsecond
for sep in (sep_icrs, sep_hcrs, sep_helioecl))
# CIRS should be the same
assert_allclose(sep_cirs, 0.0 * u.deg, atol=1 * u.microarcsecond)
def altaz_to_altaz(from_coo, to_frame):
# check if coordinates have obstimes defined
obstime = from_coo.obstime
if from_coo.obstime is None:
warnings.warn(
'Horizontal coordinate has no obstime, assuming same frame',
MissingFrameAttributeWarning)
obstime = to_frame.obstime
location = from_coo.location
if from_coo.obstime is None:
warnings.warn(
'Horizontal coordinate has no location, assuming same frame',
MissingFrameAttributeWarning)
location = to_frame.location
if obstime is None or location is None:
return to_frame.realize_frame(from_coo.spherical)
return from_coo.transform_to(CIRS(obstime=obstime)).transform_to(to_frame)
def test_cirs_itrs():
"""
Check basic CIRS<->ITRS transforms for round-tripping.
"""
ra, dec, _ = randomly_sample_sphere(200)
cirs = CIRS(ra=ra, dec=dec, obstime='J2000')
cirs6 = CIRS(ra=ra, dec=dec, obstime='J2006')
cirs2 = cirs.transform_to(ITRS).transform_to(cirs)
cirs6_2 = cirs6.transform_to(ITRS).transform_to(cirs) # different obstime
# just check round-tripping
assert_allclose(cirs.ra, cirs2.ra)
assert_allclose(cirs.dec, cirs2.dec)
assert not allclose(cirs.ra, cirs6_2.ra)
assert not allclose(cirs.dec, cirs6_2.dec)
def test_cirs_itrs():
"""
Check basic CIRS<->ITRS transforms for round-tripping.
"""
usph = golden_spiral_grid(200)
cirs = CIRS(usph, obstime='J2000')
cirs6 = CIRS(usph, obstime='J2006')
cirs2 = cirs.transform_to(ITRS()).transform_to(cirs)
cirs6_2 = cirs6.transform_to(ITRS()).transform_to(
cirs) # different obstime
# just check round-tripping
assert_allclose(cirs.ra, cirs2.ra)
assert_allclose(cirs.dec, cirs2.dec)
assert not allclose(cirs.ra, cirs6_2.ra)
assert not allclose(cirs.dec, cirs6_2.dec)
r_j2000_true = CartesianRepresentation(
[5102.50960000, 6123.01152000, 6378.13630000], unit=u.km)
rv_j2000_true = J2000(
r_j2000_true.with_differentials(v_j2000_true),
obstime=time,
representation_type="cartesian",
differential_type="cartesian",
)
# Vallado IAU 2000 - Table 3-6 CIRS
v_cirs_true = CartesianDifferential(
[-4.7453803300, 0.7903414530, 5.5319312880], unit=u.km / u.s)
r_cirs_true = CartesianRepresentation(
[5100.01840470, 6122.78636480, 6380.34453270], unit=u.km)
rv_cirs_true = CIRS(
r_cirs_true.with_differentials(v_cirs_true),
obstime=time,
representation_type="cartesian",
differential_type="cartesian",
)
# Vallado IAU 2000 - Table 3-6 ITRS
v_itrs_true = CartesianDifferential(
[-3.2256365200, -2.8724514500, 5.5319244460], unit=u.km / u.s)
r_itrs_true = CartesianRepresentation(
[-1033.4793830, 7901.29527540, 6380.35659580], unit=u.km)
rv_itrs_true = ITRS(
r_itrs_true.with_differentials(v_itrs_true),
obstime=time,
representation_type="cartesian",
differential_type="cartesian",
)
from astropy.time import Time
# ==================================
# INITIAL INPUT VALUE CALCULATIONS
# ==================================
print("Computing input values for test_CECoordinates")
# Coordinates to be observed
test = SkyCoord(83.633 * u.deg, 22.0145 * u.deg, frame='icrs')
# Observer position
earth_pos = EarthLocation(lat=0 * u.deg, lon=0 * u.deg, height=0 * u.m)
# Observation time
observing_time = Time('2000-01-01 12:00:00')
# Observing & CIRS transformation system
aa = AltAz(location=earth_pos, obstime=observing_time)
ci = CIRS(obstime=observing_time)
# Ecliptic transformation system
ec_mean = BarycentricMeanEcliptic(equinox=observing_time)
ec_true = BarycentricTrueEcliptic(equinox=observing_time)
# Now generate the converted coordinates
obs_coords = test.transform_to(aa)
zenith = 90 - obs_coords.alt.deg
cirs = test.transform_to(ci)
gal = test.transform_to(frame='galactic')
ecm = test.transform_to(ec_mean)
ect = test.transform_to(ec_true)
# Print the results
print(f"Date : {observing_time}")
print(f"In ICRS : (ra,dec) = ({test.ra}, {test.dec})")
