def test_url_ephemeris_wrong_input():
# Try loading a non-existing URL:
time = Time('1960-01-12 00:00')
with pytest.raises(HTTPError):
get_body(
'earth',
time,
ephemeris='http://data.astropy.org/path/to/nonexisting/file.bsp')
def test_file_ephemeris_wrong_input():
time = Time('1960-01-12 00:00')
# Try loading a non-existing file:
with pytest.raises(ValueError):
get_body('earth', time, ephemeris='/path/to/nonexisting/file.bsp')
# Try loading a file that does exist, but is not an ephemeris file:
with pytest.raises(ValueError):
get_body('earth', time, ephemeris=__file__)
def test_url_ephemeris_wrong_input():
# Try loading a non-existing URL:
time = Time('1960-01-12 00:00')
with pytest.raises((HTTPError, URLError)):
get_body(
'earth',
time,
ephemeris=get_pkg_data_filename('path/to/nonexisting/file.bsp'))
def test_custom_kernel_spec_body(self, bodyname):
"""
Checks that giving a kernel specifier instead of a body name works
"""
coord_by_name = get_body(bodyname, self.t, ephemeris='de432s')
kspec = BODY_NAME_TO_KERNEL_SPEC[bodyname]
coord_by_kspec = get_body(kspec, self.t, ephemeris='de432s')
assert_quantity_allclose(coord_by_name.ra, coord_by_kspec.ra)
assert_quantity_allclose(coord_by_name.dec, coord_by_kspec.dec)
assert_quantity_allclose(coord_by_name.distance, coord_by_kspec.distance)
def test_custom_kernel_spec_body(self, bodyname):
"""
Checks that giving a kernel specifier instead of a body name works
"""
coord_by_name = get_body(bodyname, self.t, ephemeris='de432s')
kspec = BODY_NAME_TO_KERNEL_SPEC[bodyname]
coord_by_kspec = get_body(kspec, self.t, ephemeris='de432s')
assert_quantity_allclose(coord_by_name.ra, coord_by_kspec.ra)
assert_quantity_allclose(coord_by_name.dec, coord_by_kspec.dec)
assert_quantity_allclose(coord_by_name.distance, coord_by_kspec.distance)
def test_file_ephemeris_wrong_input():
time = Time('1960-01-12 00:00')
# Try loading a non-existing file:
with pytest.raises(ValueError):
get_body('earth', time, ephemeris='/path/to/nonexisting/file.bsp')
# NOTE: This test currently leaves the file open (ResourceWarning).
# To fix this issue, an upstream fix is required in jplephem
# package.
# Try loading a file that does exist, but is not an ephemeris file:
with pytest.warns(ResourceWarning), pytest.raises(ValueError):
get_body('earth', time, ephemeris=__file__)
def print_planet_position(name, observer, time):
"""
Print information about the planets position
Parameters
----------
name : str
String name of planet (e.g. 'mercury' or 'jupiter')
observer : astropy.coordinates.EarthLocation
Observer object
time : astropy.time.Time
Time of the observation
"""
# Compute the observed coordinates of the object
planet = solar_system.get_body(body=name, time=time)
aa = AltAz(location=observer, obstime=time)
obs = planet.transform_to(aa)
icrs = planet.transform_to('icrs')
cirs = planet.transform_to('cirs')
# Compute the position/velocity of the object
pos, vel = solar_system.get_body_barycentric_posvel(body=name, time=time)
print(
f"{name:8}: obs=({obs.az:20.16f},{obs.zen:20.16f}) | icrs=({icrs.ra:20.16f},{icrs.dec:20.16f})"
)
print(f" cirs=({cirs.ra:20.16f},{cirs.dec:20.16f})")
print(f" pos={pos}, vel={vel}")
def test_horizons_consistency_with_precision():
"""
A test to compare at high precision against output of JPL horizons.
Tests ephemerides, and conversions from ICRS to GCRS to TETE. We are aiming for
better than 2 milli-arcsecond precision.
We use the Moon since it is nearby, and moves fast in the sky so we are
testing for parallax, proper handling of light deflection and aberration.
"""
# JPL Horizon values for 2020_04_06 00:00 to 23:00 in 1 hour steps
# JPL Horizons has a known offset (frame bias) of 51.02 mas in RA. We correct that here
ra_apparent_horizons = [
170.167332531, 170.560688674, 170.923834838, 171.271663481, 171.620188972, 171.985340827,
172.381766539, 172.821772139, 173.314502650, 173.865422398, 174.476108551, 175.144332386,
175.864375310, 176.627519827, 177.422655853, 178.236955730, 179.056584831, 179.867427392,
180.655815385, 181.409252074, 182.117113814, 182.771311578, 183.366872837, 183.902395443
] * u.deg + 51.02376467 * u.mas
dec_apparent_horizons = [
10.269112037, 10.058820647, 9.837152044, 9.603724551, 9.358956528, 9.104012390, 8.840674927,
8.571162442, 8.297917326, 8.023394488, 7.749873882, 7.479312991, 7.213246666, 6.952732614,
6.698336823, 6.450150213, 6.207828142, 5.970645962, 5.737565957, 5.507313851, 5.278462034,
5.049521497, 4.819038911, 4.585696512
] * u.deg
with solar_system_ephemeris.set('de430'):
loc = EarthLocation.from_geodetic(-67.787260*u.deg, -22.959748*u.deg, 5186*u.m)
times = Time('2020-04-06 00:00') + np.arange(0, 24, 1)*u.hour
astropy = get_body('moon', times, loc)
apparent_frame = TETE(obstime=times, location=loc)
astropy = astropy.transform_to(apparent_frame)
usrepr = UnitSphericalRepresentation(ra_apparent_horizons, dec_apparent_horizons)
horizons = apparent_frame.realize_frame(usrepr)
assert_quantity_allclose(astropy.separation(horizons), 0*u.mas, atol=1.5*u.mas)
def test_aa_high_precision():
"""
These tests are provided by @mkbrewer - see issue #10356.
The code that produces them agrees very well (<0.5 mas) with SkyField once Polar motion
is turned off, but SkyField does not include polar motion, so a comparison to Skyfield
or JPL Horizons will be ~1" off.
The absence of polar motion within Skyfield and the disagreement between Skyfield and Horizons
make high precision comparisons to those codes difficult.
"""
lat = -22.959748 * u.deg
lon = -67.787260 * u.deg
elev = 5186 * u.m
loc = EarthLocation.from_geodetic(lon, lat, elev)
t = Time('2017-04-06T00:00:00.0')
with solar_system_ephemeris.set('de430'):
moon = get_body('moon', t, loc)
moon_aa = moon.transform_to(AltAz(obstime=t, location=loc))
TARGET_AZ, TARGET_EL = 15.0326735105 * u.deg, 50.3031101339 * u.deg
TARGET_DISTANCE = 376252883.2473 * u.m
assert_allclose(moon_aa.az, TARGET_AZ, atol=2 * u.uas, rtol=0)
assert_allclose(moon_aa.alt, TARGET_EL, atol=2 * u.uas, rtol=0)
assert_allclose(moon_aa.distance, TARGET_DISTANCE, atol=2 * u.mm, rtol=0)
def test_get_sun_consistency(time):
"""
Test that the sun from JPL and the builtin get_sun match
"""
sun_jpl_gcrs = get_body('sun', time, ephemeris='de432s')
builtin_get_sun = get_sun(time)
sep = builtin_get_sun.separation(sun_jpl_gcrs)
assert sep < 0.1 * u.arcsec
def test_get_sun_consistency(time):
"""
Test that the sun from JPL and the builtin get_sun match
"""
sun_jpl_gcrs = get_body('sun', time, ephemeris='de432s')
builtin_get_sun = get_sun(time)
sep = builtin_get_sun.separation(sun_jpl_gcrs)
assert sep < 0.1*u.arcsec
def test_url_or_file_ephemeris(time):
# URL for ephemeris de432s used for testing:
url = 'http://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/planets/de432s.bsp'
# Pass the ephemeris directly as a URL.
coord_by_url = get_body('earth', time, ephemeris=url)
# Translate the URL to the cached location on the filesystem.
# Since we just used the url above, it should already have been downloaded.
filepath = download_file(url, cache=True)
# Get the coordinates using the file path directly:
coord_by_filepath = get_body('earth', time, ephemeris=filepath)
# Using the URL or filepath should give exactly the same results:
assert_quantity_allclose(coord_by_url.ra, coord_by_filepath.ra)
assert_quantity_allclose(coord_by_url.dec, coord_by_filepath.dec)
assert_quantity_allclose(coord_by_url.distance, coord_by_filepath.distance)
def test_de432s_planet(self, body):
astropy = get_body(body, self.t, ephemeris='de432s')
horizons = self.horizons[body]
# convert to true equator and equinox
astropy = _apparent_position_in_true_coordinates(astropy)
# Assert sky coordinates are close.
assert (astropy.separation(horizons) <
de432s_separation_tolerance_planets)
# Assert distances are close.
assert_quantity_allclose(astropy.distance, horizons.distance,
atol=de432s_distance_tolerance)
def test_de432s_planet(self, body):
astropy = get_body(body, self.t, ephemeris='de432s')
horizons = self.horizons[body]
# convert to true equator and equinox
astropy = astropy.transform_to(self.apparent_frame)
# Assert sky coordinates are close.
assert (astropy.separation(horizons) <
de432s_separation_tolerance_planets)
# Assert distances are close.
assert_quantity_allclose(astropy.distance, horizons.distance,
atol=de432s_distance_tolerance)
def test_aa_hd_high_precision():
"""These tests are provided by @mkbrewer - see issue #10356.
The code that produces them agrees very well (<0.5 mas) with SkyField once Polar motion
is turned off, but SkyField does not include polar motion, so a comparison to Skyfield
or JPL Horizons will be ~1" off.
The absence of polar motion within Skyfield and the disagreement between Skyfield and Horizons
make high precision comparisons to those codes difficult.
Updated 2020-11-29, after the comparison between codes became even better,
down to 100 nas.
NOTE: the agreement reflects consistency in approach between two codes,
not necessarily absolute precision. If this test starts failing, the
tolerance can and should be weakened *if* it is clear that the change is
due to an improvement (e.g., a new IAU precession model).
"""
lat = -22.959748 * u.deg
lon = -67.787260 * u.deg
elev = 5186 * u.m
loc = EarthLocation.from_geodetic(lon, lat, elev)
# Note: at this level of precision for the comparison, we have to include
# the location in the time, as it influences the transformation to TDB.
t = Time('2017-04-06T00:00:00.0', location=loc)
with solar_system_ephemeris.set('de430'):
moon = get_body('moon', t, loc)
moon_aa = moon.transform_to(AltAz(obstime=t, location=loc))
moon_hd = moon.transform_to(HADec(obstime=t, location=loc))
# Numbers from
# https://github.com/astropy/astropy/pull/11073#issuecomment-735486271
# updated in https://github.com/astropy/astropy/issues/11683
TARGET_AZ, TARGET_EL = 15.032673509956 * u.deg, 50.303110133923 * u.deg
TARGET_DISTANCE = 376252883.247239 * u.m
assert_allclose(moon_aa.az, TARGET_AZ, atol=0.1 * u.uas, rtol=0)
assert_allclose(moon_aa.alt, TARGET_EL, atol=0.1 * u.uas, rtol=0)
assert_allclose(moon_aa.distance, TARGET_DISTANCE, atol=0.1 * u.mm, rtol=0)
ha, dec = erfa.ae2hd(moon_aa.az.to_value(u.radian),
moon_aa.alt.to_value(u.radian),
lat.to_value(u.radian))
ha = u.Quantity(ha, u.radian, copy=False)
dec = u.Quantity(dec, u.radian, copy=False)
assert_allclose(moon_hd.ha, ha, atol=0.1 * u.uas, rtol=0)
assert_allclose(moon_hd.dec, dec, atol=0.1 * u.uas, rtol=0)
def test_erfa_planet(self, body, sep_tol, dist_tol):
"""Test predictions using erfa/plan94.
Accuracies are maximum deviations listed in erfa/plan94.c, for Jupiter and
Mercury, and that quoted in Meeus "Astronomical Algorithms" (1998) for the Moon.
"""
astropy = get_body(body, self.t, ephemeris='builtin')
horizons = self.horizons[body]
# convert to true equator and equinox
astropy = astropy.transform_to(self.apparent_frame)
# Assert sky coordinates are close.
assert astropy.separation(horizons) < sep_tol
# Assert distances are close.
assert_quantity_allclose(astropy.distance, horizons.distance,
atol=dist_tol)
def test_erfa_planet(self, body, sep_tol, dist_tol):
"""Test predictions using erfa/plan94.
Accuracies are maximum deviations listed in erfa/plan94.c, for Jupiter and
Mercury, and that quoted in Meeus "Astronomical Algorithms" (1998) for the Moon.
"""
astropy = get_body(body, self.t, ephemeris='builtin')
horizons = self.horizons[body]
# convert to true equator and equinox
astropy = _apparent_position_in_true_coordinates(astropy)
# Assert sky coordinates are close.
assert astropy.separation(horizons) < sep_tol
# Assert distances are close.
assert_quantity_allclose(astropy.distance, horizons.distance,
atol=dist_tol)
def test_aa_high_precision_nodata():
"""
These tests are designed to ensure high precision alt-az transforms.
They are a slight fudge since the target values come from astropy itself. They are generated
with a version of the code that passes the tests above, but for the internal solar system
ephemerides to avoid the use of remote data.
"""
TARGET_AZ, TARGET_EL = 15.0321908 * u.deg, 50.30263625 * u.deg
lat = -22.959748 * u.deg
lon = -67.787260 * u.deg
elev = 5186 * u.m
loc = EarthLocation.from_geodetic(lon, lat, elev)
t = Time('2017-04-06T00:00:00.0')
moon = get_body('moon', t, loc)
moon_aa = moon.transform_to(AltAz(obstime=t, location=loc))
assert_allclose(moon_aa.az - TARGET_AZ, 0 * u.mas, atol=0.5 * u.mas)
assert_allclose(moon_aa.alt - TARGET_EL, 0 * u.mas, atol=0.5 * u.mas)
def test_erfa_planet(self, body, sep_tol, dist_tol):
"""Test predictions using erfa/plan94.
Accuracies are maximum deviations listed in erfa/plan94.c.
"""
# Add uncertainty in position of Earth
dist_tol = dist_tol + 1300 * u.km
astropy = get_body(body, self.t, ephemeris='builtin')
horizons = self.horizons[body]
# convert to true equator and equinox
astropy = _apparent_position_in_true_coordinates(astropy)
# Assert sky coordinates are close.
assert astropy.separation(horizons) < sep_tol
# Assert distances are close.
assert_quantity_allclose(astropy.distance, horizons.distance,
atol=dist_tol)
def test_erfa_planet(self, body, sep_tol, dist_tol):
"""Test predictions using erfa/plan94.
Accuracies are maximum deviations listed in erfa/plan94.c.
"""
# Add uncertainty in position of Earth
dist_tol = dist_tol + 1300 * u.km
astropy = get_body(body, self.t, ephemeris='builtin')
horizons = self.horizons[body]
# convert to true equator and equinox
astropy = astropy.transform_to(self.apparent_frame)
# Assert sky coordinates are close.
assert astropy.separation(horizons) < sep_tol
# Assert distances are close.
assert_quantity_allclose(astropy.distance, horizons.distance,
atol=dist_tol)
def test_url_ephemeris_wrong_input():
time = Time('1960-01-12 00:00')
with pytest.raises((HTTPError, URLError)):
# A non-existent URL
get_body(
'earth',
time,
ephemeris=get_pkg_data_filename('path/to/nonexisting/file.bsp'))
with pytest.raises(HTTPError):
# A non-existent version of the JPL ephemeris
get_body('earth', time, ephemeris='de001')
with pytest.raises(ValueError):
# An invalid string
get_body('earth', time, ephemeris='not_an_ephemeris')
def test_positions_skyfield(tmpdir):
"""
Test positions against those generated by skyfield.
"""
load = Loader(tmpdir)
t = Time('1980-03-25 00:00')
location = None
# skyfield ephemeris
try:
planets = load('de421.bsp')
ts = load.timescale()
except OSError as e:
if os.environ.get('CI', False) and 'timed out' in str(e):
pytest.xfail('Timed out in CI')
else:
raise
mercury, jupiter, moon = planets['mercury'], planets[
'jupiter barycenter'], planets['moon']
earth = planets['earth']
skyfield_t = ts.from_astropy(t)
if location is not None:
earth = earth + Topos(latitude_degrees=location.lat.to_value(u.deg),
longitude_degrees=location.lon.to_value(u.deg),
elevation_m=location.height.to_value(u.m))
skyfield_mercury = earth.at(skyfield_t).observe(mercury).apparent()
skyfield_jupiter = earth.at(skyfield_t).observe(jupiter).apparent()
skyfield_moon = earth.at(skyfield_t).observe(moon).apparent()
if location is not None:
frame = TETE(obstime=t, location=location)
else:
frame = TETE(obstime=t)
ra, dec, dist = skyfield_mercury.radec(epoch='date')
skyfield_mercury = SkyCoord(ra.to(u.deg),
dec.to(u.deg),
distance=dist.to(u.km),
frame=frame)
ra, dec, dist = skyfield_jupiter.radec(epoch='date')
skyfield_jupiter = SkyCoord(ra.to(u.deg),
dec.to(u.deg),
distance=dist.to(u.km),
frame=frame)
ra, dec, dist = skyfield_moon.radec(epoch='date')
skyfield_moon = SkyCoord(ra.to(u.deg),
dec.to(u.deg),
distance=dist.to(u.km),
frame=frame)
# planet positions w.r.t true equator and equinox
moon_astropy = get_moon(t, location, ephemeris='de430').transform_to(frame)
mercury_astropy = get_body('mercury', t, location,
ephemeris='de430').transform_to(frame)
jupiter_astropy = get_body('jupiter', t, location,
ephemeris='de430').transform_to(frame)
assert (moon_astropy.separation(skyfield_moon) <
skyfield_angular_separation_tolerance)
assert (moon_astropy.separation_3d(skyfield_moon) <
skyfield_separation_tolerance)
assert (jupiter_astropy.separation(skyfield_jupiter) <
skyfield_angular_separation_tolerance)
assert (jupiter_astropy.separation_3d(skyfield_jupiter) <
skyfield_separation_tolerance)
assert (mercury_astropy.separation(skyfield_mercury) <
skyfield_angular_separation_tolerance)
assert (mercury_astropy.separation_3d(skyfield_mercury) <
skyfield_separation_tolerance)
planets.close()
def test_positions_skyfield():
"""
Test positions against those generated by skyfield.
"""
t = Time('1980-03-25 00:00')
location = None
# skyfield ephemeris
planets = load('de421.bsp')
ts = load.timescale()
mercury, jupiter, moon = planets['mercury'], planets[
'jupiter barycenter'], planets['moon']
earth = planets['earth']
skyfield_t = ts.from_astropy(t)
if location is not None:
earth = earth.topos(latitude_degrees=location.lat.to_value(u.deg),
longitude_degrees=location.lon.to_value(u.deg),
elevation_m=location.height.to_value(u.m))
skyfield_mercury = earth.at(skyfield_t).observe(mercury).apparent()
skyfield_jupiter = earth.at(skyfield_t).observe(jupiter).apparent()
skyfield_moon = earth.at(skyfield_t).observe(moon).apparent()
if location is not None:
obsgeoloc, obsgeovel = location.get_gcrs_posvel(t)
frame = GCRS(obstime=t, obsgeoloc=obsgeoloc, obsgeovel=obsgeovel)
else:
frame = GCRS(obstime=t)
ra, dec, dist = skyfield_mercury.radec(epoch='date')
skyfield_mercury = SkyCoord(ra.to(u.deg),
dec.to(u.deg),
distance=dist.to(u.km),
frame=frame)
ra, dec, dist = skyfield_jupiter.radec(epoch='date')
skyfield_jupiter = SkyCoord(ra.to(u.deg),
dec.to(u.deg),
distance=dist.to(u.km),
frame=frame)
ra, dec, dist = skyfield_moon.radec(epoch='date')
skyfield_moon = SkyCoord(ra.to(u.deg),
dec.to(u.deg),
distance=dist.to(u.km),
frame=frame)
moon_astropy = get_moon(t, location, ephemeris='de430')
mercury_astropy = get_body('mercury', t, location, ephemeris='de430')
jupiter_astropy = get_body('jupiter', t, location, ephemeris='de430')
# convert to true equator and equinox
jupiter_astropy = _apparent_position_in_true_coordinates(jupiter_astropy)
mercury_astropy = _apparent_position_in_true_coordinates(mercury_astropy)
moon_astropy = _apparent_position_in_true_coordinates(moon_astropy)
assert (moon_astropy.separation(skyfield_moon) <
skyfield_angular_separation_tolerance)
assert (moon_astropy.separation_3d(skyfield_moon) <
skyfield_separation_tolerance)
assert (jupiter_astropy.separation(skyfield_jupiter) <
skyfield_angular_separation_tolerance)
assert (jupiter_astropy.separation_3d(skyfield_jupiter) <
skyfield_separation_tolerance)
assert (mercury_astropy.separation(skyfield_mercury) <
skyfield_angular_separation_tolerance)
assert (mercury_astropy.separation_3d(skyfield_mercury) <
skyfield_separation_tolerance)
def test_positions_skyfield():
"""
Test positions against those generated by skyfield.
"""
t = Time('1980-03-25 00:00')
location = None
# skyfield ephemeris
planets = load('de421.bsp')
ts = load.timescale()
mercury, jupiter, moon = planets['mercury'], planets['jupiter barycenter'], planets['moon']
earth = planets['earth']
skyfield_t = ts.from_astropy(t)
if location is not None:
earth = earth.topos(latitude_degrees=location.lat.to_value(u.deg),
longitude_degrees=location.lon.to_value(u.deg),
elevation_m=location.height.to_value(u.m))
skyfield_mercury = earth.at(skyfield_t).observe(mercury).apparent()
skyfield_jupiter = earth.at(skyfield_t).observe(jupiter).apparent()
skyfield_moon = earth.at(skyfield_t).observe(moon).apparent()
if location is not None:
obsgeoloc, obsgeovel = location.get_gcrs_posvel(t)
frame = GCRS(obstime=t, obsgeoloc=obsgeoloc, obsgeovel=obsgeovel)
else:
frame = GCRS(obstime=t)
ra, dec, dist = skyfield_mercury.radec(epoch='date')
skyfield_mercury = SkyCoord(ra.to(u.deg), dec.to(u.deg), distance=dist.to(u.km),
frame=frame)
ra, dec, dist = skyfield_jupiter.radec(epoch='date')
skyfield_jupiter = SkyCoord(ra.to(u.deg), dec.to(u.deg), distance=dist.to(u.km),
frame=frame)
ra, dec, dist = skyfield_moon.radec(epoch='date')
skyfield_moon = SkyCoord(ra.to(u.deg), dec.to(u.deg), distance=dist.to(u.km),
frame=frame)
moon_astropy = get_moon(t, location, ephemeris='de430')
mercury_astropy = get_body('mercury', t, location, ephemeris='de430')
jupiter_astropy = get_body('jupiter', t, location, ephemeris='de430')
# convert to true equator and equinox
jupiter_astropy = _apparent_position_in_true_coordinates(jupiter_astropy)
mercury_astropy = _apparent_position_in_true_coordinates(mercury_astropy)
moon_astropy = _apparent_position_in_true_coordinates(moon_astropy)
assert (moon_astropy.separation(skyfield_moon) <
skyfield_angular_separation_tolerance)
assert (moon_astropy.separation_3d(skyfield_moon) < skyfield_separation_tolerance)
assert (jupiter_astropy.separation(skyfield_jupiter) <
skyfield_angular_separation_tolerance)
assert (jupiter_astropy.separation_3d(skyfield_jupiter) <
skyfield_separation_tolerance)
assert (mercury_astropy.separation(skyfield_mercury) <
skyfield_angular_separation_tolerance)
assert (mercury_astropy.separation_3d(skyfield_mercury) <
skyfield_separation_tolerance)