def test_regression_5085():
"""
PR #5085 was put in place to fix the following issue.
Issue: https://github.com/astropy/astropy/issues/5069
At root was the transformation of Ecliptic coordinates with
non-scalar times.
"""
# Note: for regression test, we need to be sure that we use UTC for the
# epoch, even though more properly that should be TT; but the "expected"
# values were calculated using that.
j2000 = Time('J2000', scale='utc')
times = Time(["2015-08-28 03:30", "2015-09-05 10:30", "2015-09-15 18:35"])
latitudes = Latitude([3.9807075, -5.00733806, 1.69539491]*u.deg)
longitudes = Longitude([311.79678613, 72.86626741, 199.58698226]*u.deg)
distances = u.Quantity([0.00243266, 0.0025424, 0.00271296]*u.au)
coo = GeocentricMeanEcliptic(lat=latitudes,
lon=longitudes,
distance=distances, obstime=times, equinox=times)
# expected result
ras = Longitude([310.50095400, 314.67109920, 319.56507428]*u.deg)
decs = Latitude([-18.25190443, -17.1556676, -15.71616522]*u.deg)
distances = u.Quantity([1.78309901, 1.710874, 1.61326649]*u.au)
expected_result = GCRS(ra=ras, dec=decs,
distance=distances, obstime=j2000).cartesian.xyz
actual_result = coo.transform_to(GCRS(obstime=j2000)).cartesian.xyz
assert_quantity_allclose(expected_result, actual_result)
def test_regression_5085():
"""
PR #5085 was put in place to fix the following issue.
Issue: https://github.com/astropy/astropy/issues/5069
At root was the transformation of Ecliptic coordinates with
non-scalar times.
"""
# Note: for regression test, we need to be sure that we use UTC for the
# epoch, even though more properly that should be TT; but the "expected"
# values were calculated using that.
j2000 = Time('J2000', scale='utc')
times = Time(["2015-08-28 03:30", "2015-09-05 10:30", "2015-09-15 18:35"])
latitudes = Latitude([3.9807075, -5.00733806, 1.69539491]*u.deg)
longitudes = Longitude([311.79678613, 72.86626741, 199.58698226]*u.deg)
distances = u.Quantity([0.00243266, 0.0025424, 0.00271296]*u.au)
coo = GeocentricMeanEcliptic(lat=latitudes,
lon=longitudes,
distance=distances, obstime=times, equinox=times)
# expected result
ras = Longitude([310.50095400, 314.67109920, 319.56507428]*u.deg)
decs = Latitude([-18.25190443, -17.1556676, -15.71616522]*u.deg)
distances = u.Quantity([1.78309901, 1.710874, 1.61326649]*u.au)
expected_result = GCRS(ra=ras, dec=decs,
distance=distances, obstime=j2000).cartesian.xyz
actual_result = coo.transform_to(GCRS(obstime=j2000)).cartesian.xyz
assert_quantity_allclose(expected_result, actual_result)
def apparent_longitude(t='now'):
"""
Returns the Sun's apparent longitude, referred to the true equinox of date. Corrections for
nutation and aberration (for Earth motion) are included.
Parameters
----------
t : {parse_time_types}
A time (usually the start time) specified as a parse_time-compatible
time string, number, or a datetime object.
Notes
-----
The nutation model is IAU 2000A nutation with adjustments to match IAU 2006 precession.
"""
time = parse_time(t)
sun = SkyCoord(0*u.deg, 0*u.deg, 0*u.AU, frame='hcrs', obstime=time)
coord = sun.transform_to(GeocentricMeanEcliptic(equinox=time))
# Astropy's GeocentricMeanEcliptic already includes aberration, so only add nutation
jd1, jd2 = get_jd12(time, 'tt')
nut_lon, _ = erfa.nut06a(jd1, jd2)*u.radian
lon = coord.lon + nut_lon
return Longitude(lon)
def apparent_latitude(t='now'):
"""
Returns the Sun's apparent latitude, referred to the true equinox of date. Corrections for
nutation and aberration (for Earth motion) are included.
Parameters
----------
t : {parse_time_types}
Time to use in a parse-time-compatible format
"""
time = parse_time(t)
sun = SkyCoord(0 * u.deg, 0 * u.deg, 0 * u.AU, frame='hcrs', obstime=time)
coord = sun.transform_to(GeocentricMeanEcliptic(equinox=time))
# Astropy's GeocentricMeanEcliptic does not include nutation, but the contribution is negligible
lat = coord.lat
return Latitude(lat)
def true_latitude(t='now'):
"""
Returns the Sun's true geometric latitude, referred to the mean equinox of date. No
corrections for nutation or aberration are included.
Parameters
----------
t : {parse_time_types}
Time to use in a parse-time-compatible format
"""
time = parse_time(t)
sun = SkyCoord(0 * u.deg, 0 * u.deg, 0 * u.AU, frame='hcrs', obstime=time)
coord = sun.transform_to(GeocentricMeanEcliptic(equinox=time))
# Astropy's GeocentricMeanEcliptic includes aberration from Earth motion, but the contribution
# is negligible
lat = coord.lat
return Latitude(lat)
