def test_simple():
c = coord.ICRS(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree))
c.transform_to(GD1Koposov10)
c = coord.Galactic(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree))
c.transform_to(GD1Koposov10)
c = GD1Koposov10(217.2141 * u.degree, -11.4351 * u.degree)
c.transform_to(coord.ICRS)
c.transform_to(coord.Galactic)
c = coord.Galactic(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree))
s = c.transform_to(GD1Koposov10)
# with distance
c = GD1Koposov10(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree),
distance=15 * u.kpc)
c.transform_to(coord.ICRS)
c2 = c.transform_to(coord.Galactic)
assert np.allclose(c2.distance.value, c.distance.value)
# TODO: remove this in next version
# For now: make sure old class still works
from astropy.tests.helper import catch_warnings
with catch_warnings(DeprecationWarning) as w:
c = GD1(217.2141 * u.degree, -11.4351 * u.degree)
assert len(w) > 0
c2 = c.transform_to(coord.Galactic)
c3 = c2.transform_to(GD1)
assert np.allclose(c3.phi1.degree, c.phi1.degree)
assert np.allclose(c3.phi2.degree, c.phi2.degree)
def show_milkyway(self,
b=None,
nbins=100,
l_start=-241,
l_stop=116,
**kwargs):
""" """
from astropy import coordinates, units
nbins = 100
if b is None:
gal = coordinates.Galactic(
np.linspace(l_start, l_stop, nbins) * units.deg,
np.zeros(nbins) * units.deg).transform_to(coordinates.ICRS)
prop = dict(ls="-", color="0.7", alpha=0.5)
self.ax.plot(*self.radec_to_plot(gal.ra, gal.dec), **{
**prop,
**kwargs
})
else:
gal_dw = coordinates.Galactic(
np.linspace(l_start, l_stop, 100) * units.deg,
+b * np.ones(nbins) * units.deg).transform_to(coordinates.ICRS)
gal_up = coordinates.Galactic(
np.linspace(l_start, l_stop, 100) * units.deg,
-b * np.ones(nbins) * units.deg).transform_to(coordinates.ICRS)
ra_dw, dec_dw = self.radec_to_plot(gal_dw.ra, gal_dw.dec)
ra_up, dec_up = self.radec_to_plot(gal_up.ra, gal_up.dec)
prop = dict(facecolor="0.7", alpha=0.2)
self.ax.fill_between(ra_dw, dec_dw, dec_up, **{**prop, **kwargs})
def posang(l1, b1, l2, b2, system='galactic', units='degrees', **kwargs):
"""
Return the position angle between two points assuming a rectilinear
coordinate system (I think; at the very least I am making no corrections
for wcs).
INPUT:
longitude1, latitude1, longitude2, latitude2
Defaults to GALACTIC coordinates. **kwargs are passed to coords.Position
"""
if system.lower() == 'galactic':
pos1 = coordinates.Galactic(l1, b1, unit=('deg', 'deg'))
pos2 = coordinates.Galactic(l2, b2, unit=('deg', 'deg'))
elif system.lower() in ('radec', 'fk5', 'icrs'):
pos1 = coordinates.ICRS(l1, b1, unit=('deg', 'deg'))
pos2 = coordinates.ICRS(l2, b2, unit=('deg', 'deg'))
ra1, dec1 = pos1.icrs.ra.deg, pos1.icrs.dec.deg
ra2, dec2 = pos2.icrs.ra.deg, pos2.icrs.dec.deg
radiff = (ra1 - ra2) / 180. * pi
angle = arctan2(
sin(radiff),
cos(dec1 * pi / 180.) * tan(dec2 * pi / 180.) -
sin(dec1 * pi / 180.) * cos(radiff))
if units == 'degrees':
return angle / pi * 180
elif units == 'radians':
return angle
else:
raise ValueError("Invalid units: %s" % units)
def test_vhel_to_vgsr():
filename = get_pkg_data_filename('idl_vgsr_vhel.txt')
data = np.genfromtxt(filename, names=True, skip_header=2)
# one row
row = data[0]
l = coord.Angle(row["lon"] * u.degree)
b = coord.Angle(row["lat"] * u.degree)
c = coord.Galactic(l, b)
vhel = row["vhelio"] * u.km / u.s
vlsr = [row["vx"], row["vy"], row["vz"]] * u.km / u.s # this is right
vcirc = row["vcirc"] * u.km / u.s
vsun = vlsr + [0, 1, 0] * vcirc
vgsr = vhel_to_vgsr(c, vhel, vsun=vsun)
np.testing.assert_almost_equal(vgsr.value, row['vgsr'], decimal=4)
# now check still get right answer passing in ICRS coordinates
vgsr = vhel_to_vgsr(c.transform_to(coord.ICRS), vhel, vsun=vsun)
np.testing.assert_almost_equal(vgsr.value, row['vgsr'], decimal=4)
# all together now
l = coord.Angle(data["lon"] * u.degree)
b = coord.Angle(data["lat"] * u.degree)
c = coord.Galactic(l, b)
vhel = data["vhelio"] * u.km / u.s
vgsr = vhel_to_vgsr(c, vhel, vsun=vsun)
np.testing.assert_almost_equal(vgsr.value, data['vgsr'], decimal=4)
# now check still get right answer passing in ICRS coordinates
vgsr = vhel_to_vgsr(c.transform_to(coord.ICRS), vhel, vsun=vsun)
np.testing.assert_almost_equal(vgsr.value, data['vgsr'], decimal=4)
def test_vgsr_to_vhel():
filename = get_pkg_data_filename('idl_vgsr_vhel.txt')
data = np.genfromtxt(filename, names=True, skip_header=2)
# one row
row = data[0]
l = coord.Angle(row["lon"] * u.degree)
b = coord.Angle(row["lat"] * u.degree)
c = coord.Galactic(l, b)
vgsr = row["vgsr"] * u.km / u.s
vlsr = [row["vx"], row["vy"], row["vz"]] * u.km / u.s # this is right
vcirc = row["vcirc"] * u.km / u.s
vsun = vlsr + [0, 1, 0] * vcirc
vhel = vgsr_to_vhel(c, vgsr, vsun=vsun)
assert np.allclose(vhel.value, row['vhelio'], atol=1e-3)
# now check still get right answer passing in ICRS coordinates
vhel = vgsr_to_vhel(c.transform_to(coord.ICRS), vgsr, vsun=vsun)
assert np.allclose(vhel.value, row['vhelio'], atol=1e-3)
# all together now
l = coord.Angle(data["lon"] * u.degree)
b = coord.Angle(data["lat"] * u.degree)
c = coord.Galactic(l, b)
vgsr = data["vgsr"] * u.km / u.s
vhel = vgsr_to_vhel(c, vgsr, vsun=vsun)
assert np.allclose(vhel.value, data['vhelio'], atol=1e-3)
# now check still get right answer passing in ICRS coordinates
vhel = vgsr_to_vhel(c.transform_to(coord.ICRS), vgsr, vsun=vsun)
assert np.allclose(vhel.value, data['vhelio'], atol=1e-3)
def test_simple():
c = coord.ICRS(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree))
c.transform_to(Sagittarius)
c = coord.Galactic(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree))
c.transform_to(Sagittarius)
c = Sagittarius(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree))
c.transform_to(coord.ICRS)
c.transform_to(coord.Galactic)
c = coord.Galactic(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree))
s = c.transform_to(Sagittarius)
# with distance
c = Sagittarius(coord.Angle(217.2141, u.degree),
coord.Angle(-11.4351, u.degree),
distance=15 * u.kpc)
c.transform_to(coord.ICRS)
c2 = c.transform_to(coord.Galactic)
assert c2.distance.value == c.distance.value
def __init__(self):
self._month_transit = np.linspace(0., 365., 13)
self._days_of_year = np.linspace(0., 365., 366)
ep_rot_1 = np.array([0.9931, 0.1170, -0.01032]) # 1st quadrant
ep_rot_2 = np.array([-0.0670, 0.4927, -0.8676]) # 2nd quadrant
ep_rot_1_b = np.arcsin(ep_rot_1[2])
ep_rot_1_l = np.arccos(ep_rot_1[0] / np.cos(ep_rot_1_b))
ep_rot_2_b = np.arcsin(ep_rot_2[2])
ep_rot_2_l = np.arccos(ep_rot_2[0] / np.cos(ep_rot_2_b))
ep_rot_1_gal = coord.Galactic(l=ep_rot_1_l * u.rad,
b=ep_rot_1_b * u.rad,
distance=1000. * u.kpc)
ep_rot_2_gal = coord.Galactic(l=ep_rot_2_l * u.rad,
b=ep_rot_2_b * u.rad,
distance=1000. * u.kpc)
ep_rot_1_galcen = ep_rot_1_gal.transform_to(coord.Galactocentric)
ep_rot_2_galcen = ep_rot_2_gal.transform_to(coord.Galactocentric)
self._ep_rot_1_galcen_vec = np.array([ep_rot_1_galcen.transform_to(coord.Galactocentric).x/(1000.*u.kpc), \
ep_rot_1_galcen.transform_to(coord.Galactocentric).y/(1000.*u.kpc), \
ep_rot_1_galcen.transform_to(coord.Galactocentric).z/(1000.*u.kpc)])
self._ep_rot_2_galcen_vec = np.array([ep_rot_2_galcen.transform_to(coord.Galactocentric).x/(1000.*u.kpc), \
ep_rot_2_galcen.transform_to(coord.Galactocentric).y/(1000.*u.kpc), \
ep_rot_2_galcen.transform_to(coord.Galactocentric).z/(1000.*u.kpc)])
return
def test_query_region_async(patch_get):
response = ukidss.core.Ukidss.query_region_async(coord.Galactic(
l=10.625, b=-0.38, unit=(u.deg, u.deg)),
radius=6 * u.arcsec,
get_query_payload=True)
assert response['radius'] == 0.1
response = ukidss.core.Ukidss.query_region_async(coord.Galactic(
l=10.625, b=-0.38, unit=(u.deg, u.deg)),
radius=6 * u.arcsec)
assert response is not None
def draw_single_pointing_expo(n,
l_p,
b_p,
D_linear,
frac_dust,
pm,
radius_plate,
dust=True):
"""
Draws positions R, z, l, b, D in single pointings
arguments
n = initial number of points to sample from
l_p = longitude pointing (deg)
b_p = latitude pointing (deg)
Dmin_p, D_maxp = min and max distances in pointing
Rd = scale length (approximate)
hz = scale height (approximate)
frankel 2018
"""
# Galactocentric dist & height along the pointing
c = coord.Galactic(l=l_p * un.degree,
b=b_p * un.degree,
distance=D_linear * un.kpc)
cc = c.transform_to(coord.Galactocentric)
x, y, z = cc.x.value, cc.y.value, cc.z.value
R_along = np.sqrt(x * x + y * y)
z_along = z
# distribution evaluation
p = nu_Rz(R_along, z_along, pm) * D_linear * D_linear
# dust
if dust == True:
p *= frac_dust
# cumulative distribution:
F_cumul = f_cumul(D_linear, p)
u = np.random.rand(n) * np.max(F_cumul)
D = np.interp(u, F_cumul, D_linear)
l_s, b_s, D = cone.make_cone_lbd(D, l_p, b_p, radius_plate)
cs = coord.Galactic(l=l_s * un.degree,
b=b_s * un.degree,
distance=D * un.kpc)
ccs = cs.transform_to(coord.Galactocentric)
xs, ys, zs = ccs.x.value, ccs.y.value, ccs.z.value
R = np.sqrt(xs * xs + ys * ys)
z = zs
return R, z, l_s, b_s, D, np.max(F_cumul)
def test_get_images_async(patch_post, patch_parse_coordinates):
response = magpis.core.Magpis.get_images_async(coord.Galactic(
10.5, 0.0, unit=(u.deg, u.deg)),
image_size=2 * u.deg,
survey="gps6epoch3",
get_query_payload=True)
npt.assert_approx_equal(response['ImageSize'], 120, significant=3)
assert response['Survey'] == 'gps6epoch3'
response = magpis.core.Magpis.get_images_async(
coord.Galactic(10.5, 0.0, unit=(u.deg, u.deg)))
assert response is not None
def test_vgsr_to_vhel_misc():
# make sure it works with longitude in 0-360 or -180-180
l1 = coord.Angle(190. * u.deg)
l2 = coord.Angle(-170. * u.deg)
b = coord.Angle(30. * u.deg)
c1 = coord.Galactic(l1, b)
c2 = coord.Galactic(l2, b)
vgsr = -110. * u.km / u.s
vhel1 = vgsr_to_vhel(c1, vgsr)
vhel2 = vgsr_to_vhel(c2, vgsr)
np.testing.assert_almost_equal(vhel1.value, vhel2.value, decimal=9)
def test_vgsr_to_vhel_misc():
# make sure it works with longitude in 0-360 or -180-180
l1 = coord.Angle(190. * u.deg)
l2 = coord.Angle(-170. * u.deg)
b = coord.Angle(30. * u.deg)
c1 = coord.Galactic(l1, b)
c2 = coord.Galactic(l2, b)
vgsr = -110. * u.km / u.s
vhel1 = vgsr_to_vhel(c1, vgsr)
vhel2 = vgsr_to_vhel(c2, vgsr)
assert np.allclose(vhel1.value, vhel2.value)
def _mcmc_sample_to_coord(self, p):
_, orbit_pars = self._unpack_orbit(0, p)
rep = coord.SphericalRepresentation(lon=[0.] * u.radian,
lat=[orbit_pars['phi2']] *
u.radian,
distance=[orbit_pars['d']] * u.kpc)
return coord.Galactic(orbitfit.rotate_sph_coordinate(rep, self.R.T))
def set_transformed_coordinates(table):
"""
Set GeocentricTrueEcliptic and Galactic coordinate tranformations
from `astropy.coordinates`.
"""
from astropy import coordinates
import astropy.units as u
coo = coordinates.SkyCoord(ra=table['ra'] * u.deg,
dec=table['dec'] * u.deg)
table.rd = coo
ecl = coo.transform_to(coordinates.GeocentricTrueEcliptic())
table['ecl_lat'] = ecl.lat
table['ecl_lat'].format = '.1f'
table['ecl_lon'] = ecl.lon
table['ecl_lon'].format = '.1f'
gal = coo.transform_to(coordinates.Galactic())
table['gal_l'] = gal.l
table['gal_l'].format = '.1f'
table['gal_b'] = gal.b
table['gal_b'].format = '.1f'
def test_get_images_2(self):
images = ukidss.core.Ukidss.get_images(coord.Galactic(l=49.489,
b=-0.27,
unit=(u.deg,
u.deg)),
image_width=5 * u.arcmin)
assert images is not None
def test_frames(tmpdir):
frames = [
cf.CelestialFrame(reference_frame=coord.ICRS()),
cf.CelestialFrame(reference_frame=coord.FK5(
equinox=time.Time('2010-01-01'))),
cf.CelestialFrame(reference_frame=coord.FK4(
equinox=time.Time('2010-01-01'), obstime=time.Time('2015-01-01'))),
cf.CelestialFrame(reference_frame=coord.FK4NoETerms(
equinox=time.Time('2010-01-01'), obstime=time.Time('2015-01-01'))),
cf.CelestialFrame(reference_frame=coord.Galactic()),
cf.CelestialFrame(
reference_frame=coord.Galactocentric(galcen_distance=5.0 * u.m,
galcen_ra=45 * u.deg,
galcen_dec=1 * u.rad,
z_sun=3 * u.pc,
roll=3 * u.deg)),
cf.CelestialFrame(
reference_frame=coord.GCRS(obstime=time.Time('2010-01-01'),
obsgeoloc=[1, 3, 2000] * u.pc,
obsgeovel=[2, 1, 8] * (u.m / u.s))),
cf.CelestialFrame(reference_frame=coord.CIRS(
obstime=time.Time('2010-01-01'))),
cf.CelestialFrame(reference_frame=coord.ITRS(
obstime=time.Time('2022-01-03'))),
cf.CelestialFrame(reference_frame=coord.PrecessedGeocentric(
obstime=time.Time('2010-01-01'),
obsgeoloc=[1, 3, 2000] * u.pc,
obsgeovel=[2, 1, 8] * (u.m / u.s)))
]
tree = {'frames': frames}
helpers.assert_roundtrip_tree(tree, tmpdir)
def main(pool, distance=20, filename='output_file.txt', nside=64):
#calculate pole centers
hp = HEALPix(nside=nside, order='ring', frame=coord.Galactic())
centers = hp.healpix_to_skycoord(np.arange(0, hp.npix))
#only keep poles above equator to not redo calculate with opposite pole
centers = centers[centers.b >= 0.0 * u.deg]
#pad centers to match to number of processors
ncenters = centers.shape[0]
nprocs = pool.size
if nprocs == 0.:
nprocs = 1
ncenters_per_proc = np.ceil(ncenters / float(nprocs))
npads = nprocs * ncenters_per_proc - ncenters
skypad = coord.SkyCoord(np.zeros(int(npads)),
np.zeros(int(npads)),
frame='galactic',
unit=u.deg)
centers = coord.concatenate((centers, skypad))
#reshape centers so each worker gets a block of them
centers = centers.reshape(nprocs, int(ncenters_per_proc))
print('number of workers: ', nprocs)
print('number of poles: ', ncenters)
print('number of poles per worker: ', ncenters_per_proc)
print('number of poles added as padding: ', npads)
print('shape of poles array: ', np.shape(centers))
#instantiate worker with filename results will be saved to
worker = Worker(filename, args.dist)
#you better work !
for r in pool.map(worker, list(centers), callback=worker.callback):
pass
def reflex(c):
#c = coord.(c)
v_sun = coord.Galactocentric.galcen_v_sun
observed = c.transform_to(coord.Galactic)
rep = observed.cartesian.without_differentials()
rep = rep.with_differentials(observed.cartesian.differentials['s'] + v_sun)
return coord.Galactic(rep).transform_to(c.frame)
def gal2cel(regfile):
"""
Converts a region file from galactic to celestial coordinates including
position angle reference from the center of the box (right now only works
on box regions)
Requires pyregion with the ShapeList.write() function implemented...
not clear if that exists in 1.0
"""
reg = pyregion.open(regfile)
for R in reg:
if R.name == 'box':
x, y, dx, dy, angle = R.coord_list
#posn = coords.Position([x,y],system='galactic')
#ra,dec = posn.j2000()
posn = coordinates.Galactic(x * u.deg, y * u.deg)
ra, dec = posn.fk5.ra.deg, posn.fk5.dec.deg
newang = posang.posang(x - dx, y, x + dx, y, system='galactic')
coord_list = [ra, dec, dx, dy, angle - newang - 90]
R.coord_format = 'fk5'
R.coord_list = coord_list
R.params = coord_list
reg.write(regfile[:-4] + "_fk5.reg")
def test_ogle_list(patch_post):
"""
Test multiple pointings using a list of astropy coordinate instances
"""
co = coord.Galactic(0, 3, unit=(u.degree, u.degree))
co_list = [co, co, co]
ogle.core.Ogle.query_region(coord=co_list)
def test_vhel_to_vgsr_misc():
vhel = 110*u.km/u.s
c1 = coord.Galactic(15*u.deg, -0.6*u.deg)
# make sure throws error if tuple elements are not Quantities
with pytest.raises(TypeError):
vhel_to_vgsr(c1, vhel.value)
def test_table():
""" Test the transformation code against table 2 values from
Newberg et al. 2010 (below)
"""
names = ["l", "b", "db", "Lambda", "Beta", "g0", "dg0"]
table = """255 48.5 0.7 22.34 0.08 17.1 0.1
245 52.0 0.7 15.08 0.56 0. 0.
235 53.5 0.7 8.86 0.21 0. 0.
225 54.0 0.7 2.95 -0.23 17.6 0.2
215 54.0 0.7 -2.93 -0.33 17.9 0.1
205 53.5 0.7 -8.85 -0.09 18.0 0.1
195 52.0 0.7 -15.08 0.05 0. 0.
185 50.5 0.7 -21.42 1.12 18.6 0.1
175 47.5 0.7 -28.59 1.88 0. 0.
171 45.8 1.0 -31.81 2.10 0. 0."""
table = ascii.read(table, names=names)
for line in table:
galactic = coord.Galactic(l=line['l'] * u.deg, b=line['b'] * u.deg)
orp = galactic.transform_to(Orphan)
true_orp = Orphan(Lambda=line['Lambda'] * u.deg,
Beta=line['Beta'] * u.deg)
# TODO: why does this suck so badly?
assert true_orp.separation(orp) < 20 * u.arcsec
def test_get_images_2(self):
images = vista.core.Vista.get_images(coord.Galactic(l=330.1,
b=-0.1,
unit=(u.deg,
u.deg)),
image_width=5 * u.arcmin)
assert images is not None
def test_init_center():
stupid_gal = GreatCircleICRSFrame(
pole=coord.Galactic._ngp_J2000.transform_to(coord.ICRS),
center=coord.Galactocentric.galcen_coord)
gal = coord.Galactic(50*u.deg, 20*u.deg)
gal2 = gal.transform_to(stupid_gal)
assert np.isclose(gal.l.degree, gal2.phi1.degree)
assert np.isclose(gal.b.degree, gal2.phi2.degree)
def test_query_region(patch_get, patch_get_readable_fileobj):
table = ukidss.core.Ukidss.query_region(coord.Galactic(l=10.625,
b=-0.38,
unit=(u.deg,
u.deg)),
radius=6 * u.arcsec)
assert isinstance(table, Table)
assert len(table) > 0
def test_query_region(self):
table = vista.core.Vista.query_region(coord.Galactic(l=340.5,
b=-0.38,
unit=(u.deg,
u.deg)),
radius=6 * u.arcsec)
assert isinstance(table, Table)
assert len(table) > 0
def test_get_images(self):
image = magpis.core.Magpis.get_images(coord.Galactic(10.5,
0.0,
unit=(u.deg,
u.deg)),
image_size='1 arcmin')
assert image is not None
assert image[0].data.shape == (8, 8)
def get_nir_cat(self, clobber=False, use_twomass=True):
"""
Get the NIR catalog
Catalog (necessary for zero-point determination) is saved
into self.data_dir as
self.name+"_"+self.nir_survey+"cat.fits"
"""
print("Fetching NIR catalog from server...")
if use_twomass:
if (not os.path.isfile(self.nir_cal_cat)) or clobber:
from astroquery.irsa import Irsa
Irsa.ROW_LIMIT = 2000.
table = Irsa.query_region(coordinates.Galactic(l=self.glon,
b=self.glat,
unit=(u.deg,
u.deg)),
catalog="fp_psc",
spatial="Box",
width=self.nir_im_size)
#print(table)
#IPAC table does not take overwrite? But FITS does? So inconsistent and bad
table.write(self.nir_cal_cat,
format='votable',
overwrite=clobber)
else:
print(
"NIR catalog already downloaded. Use clobber=True to fetch new versions."
)
else:
if (not os.path.isfile(self.nir_cat)) or clobber:
if self.nir_survey == "VISTA":
from astroquery.vista import Vista as NIR
if self.nir_survey == "UKIDSS":
from astroquery.ukidss import Ukidss as NIR
table = NIR.query_region(coordinates.Galactic(l=self.glon,
b=self.glat,
unit=(u.deg,
u.deg)),
radius=self.nir_im_size)
table.write(self.nir_cat, format="fits", overwrite=clobber)
else:
print(
"NIR catalog already downloaded. Use clobber=True to fetch new versions."
)
def test_transform():
rep = coord.CartesianRepresentation(x=1, y=2, z=3, unit=u.pc)
ref_c1 = ReferencePlaneFrame(rep)
with pytest.raises(ValueError):
ref_c1.transform_to(coord.ICRS)
with pytest.raises(ValueError):
ref_c2 = ReferencePlaneFrame(rep, origin=coord.Galactic())
def test_vgsr_to_vhel_misc():
# make sure it works with longitude in 0-360 or -180-180
l1 = coord.Angle(190.*u.deg)
l2 = coord.Angle(-170.*u.deg)
b = coord.Angle(30.*u.deg)
c1 = coord.Galactic(l1, b)
c2 = coord.Galactic(l2, b)
vgsr = -110.*u.km/u.s
vhel1 = vgsr_to_vhel(c1,vgsr)
vhel2 = vgsr_to_vhel(c2,vgsr)
np.testing.assert_almost_equal(vhel1.value, vhel2.value, decimal=9)
# make sure throws error if tuple elements are not Quantities
with pytest.raises(TypeError):
vgsr_to_vhel(c1, vgsr.value)
