def dmod(redshift,dist=False):
if dist:
dist_10pc = redshift.to(u.parsec).value/10.
else:
dist_10pc = Distance(z=redshift).parsec/10.
dm=5*np.log10(dist_10pc-5)
return dm
def __init__(self,
afn,
sep,
distance,
_PA=np.NaN * u.deg,
*,
differentials=None,
copy: bool = True,
afn_name: T.Optional[str] = None):
if differentials is not None: # TODO, allow differentials
raise ValueError()
super().__init__(
afn,
sep,
distance,
_PA=_PA,
copy=copy,
differentials=differentials,
)
if self._distance.unit.physical_type == "length":
try:
self._distance = Distance(self._distance, copy=False)
except ValueError as e:
if e.args[0].startswith("Distance must be >= 0"):
raise ValueError(
"Distance must be >= 0. To allow negative "
"distance values, you must explicitly pass"
" in a `Distance` object with the the "
"argument 'allow_negative=True'.")
else:
raise
def get(self, name):
"""Load the data on the star from the local database, or online
if not available locally.
Parameters
----------
name : str
Name of the star / planet
Returns
-------
star : exoorbit.bodies.Star
recovered Star
"""
# self.backend.auto_fill(name)
data = self.backend.load(name)
if "distance" in data:
distance = data["distance"]
elif "parallax" in data:
distance = Distance(parallax=data["parallax"])
else:
distance = None
# Convert names
# Stellar parameters
star = Star(
name=name,
mass=data.get("mass"),
radius=data.get("radius"),
teff=data.get("t_eff"),
logg=data.get("logg"),
monh=data.get("metallicity"),
vmac=data.get("velocity_turbulence", 1 * u.km/u.s),
coordinates=data.get("coordinates"),
distance=distance,
radial_velocity=data.get("radial_velocity"),
)
planets = {}
for pname, p in data["planets"].items():
planet = Planet(
name=pname,
radius=p.get("radius"),
mass=p.get("mass"),
inc=p.get("inclination", 90 * u.deg),
sma=p.get("semi_major_axis", 0 * u.AU),
period=p.get("period"),
ecc=p.get("eccentricity"),
omega=p.get("periastron", 90 * u.deg),
time_of_transit=p.get("transit_epoch"),
transit_duration=p.get("transit_duration", 0 * u.day),
)
planets[pname] = planet
star.planets = planets
return star
def flux_to_nulnu(flux, z, wav, ld=None, lsun=None, cosmo=None,mujy=None):
if cosmo is None:
# print 'no preset cosmology,use FlatLCDM w/ h0.7'
cosmo = FlatLambdaCDM(H0=70, Om0=0.3)
dlum = Distance(z=z, unit=u.cm, cosmology=cosmo).value
freq = 3e14/wav
if mujy:jy2erg=1e29
else:jy2erg=1e23
nulnu = np.log10(flux*4*np.pi*dlum**2*freq/((1.+z)*jy2erg))
if lsun is True:
nulnu -= 33.5827
return nulnu
def flux_to_nulnu(flux, z, wav, ld=None, lsun=None, cosmo=None, mujy=None):
# convert a flux to nulnu at a certain wavelength in the unit of erg/s
# wav should be in micron, and flux should be in Jy
if cosmo is None:
# print 'no preset cosmology,use FlatLCDM w/ h0.7'
cosmo = FlatLambdaCDM(H0=70, Om0=0.3)
dlum = Distance(z=z, unit=u.cm, cosmology=cosmo).value
freq = 3e14 / wav
if mujy: jy2erg = 1e29
else: jy2erg = 1e23
nulnu = np.log10(flux * 4 * np.pi * dlum**2 * freq / ((1. + z) * jy2erg))
if lsun is True:
nulnu -= 33.5827
return nulnu
assert_allclose([m31_in_m31.lon, m31_in_m31.lat], [0, 0] * u.deg,
atol=1e-10 * u.deg)
assert_allclose([m33_in_m31.lon, m33_in_m31.lat],
[11.13135175, -9.79084759] * u.deg)
assert_allclose(m33.separation(m31),
np.hypot(m33_in_m31.lon, m33_in_m31.lat),
atol=.1 * u.deg)
# used below in the next parametrized test
m31_sys = [ICRS, FK5, Galactic]
m31_coo = [(10.6847929, 41.2690650), (10.6847929, 41.2690650),
(121.1744050, -21.5729360)]
m31_dist = Distance(770, u.kpc)
convert_precision = 1 * u.arcsec
roundtrip_precision = 1e-4 * u.degree
dist_precision = 1e-9 * u.kpc
m31_params = []
for i in range(len(m31_sys)):
for j in range(len(m31_sys)):
if i < j:
m31_params.append((m31_sys[i], m31_sys[j], m31_coo[i], m31_coo[j]))
@pytest.mark.parametrize(('fromsys', 'tosys', 'fromcoo', 'tocoo'), m31_params)
def test_m31_coord_transforms(fromsys, tosys, fromcoo, tocoo):
"""
This tests a variety of coordinate conversions for the Chandra point-source
def find_opp_and_retro(self, start_time):
cur_time = Time(start_time)
last_RA = 0.
last_dist = Distance(999, unit=units.au)
pre_closest = True
self.retrograding = False
retro_start = None
retro_end = None
opptime = None
# Earth location to use for calculating Mars' position.
# Setting it to None will (I think? docs aren't clear) calculate
# from the center of the Earth; this is much faster, skips
# calculations like parallax due to earth's rotation,
# and avoids seeing a lot of spurious retrograde/direct
# transitions due solely to the observer's position changing
# as the earth rotates.
location = None
# A place to store the data points
self.planettrack = []
# When a planet is approaching opposition, its elongation is negative.
# When it flips to positive (-180 to 180), it just passed opposition.
# Can't check for exactly 180 if we're only checking time coarsely.
last_elong = -1
# We'll look for the end of retrograde then go a few days
# past it; but first, put a limit on how far we can go.
end_time = cur_time + TimeDelta(300, format='jd')
# Initially, go one day at a time:
coarsemode = TimeDelta(1, format='jd')
# but in fine mode, we'll go one hour at a time:
finemode = TimeDelta(60 * 60, format='sec')
# and near opposition we'll go even finer for a few days:
superfinemode = TimeDelta(60 * 5, format='sec')
timeslice = coarsemode
while cur_time < end_time:
cur_time += timeslice
mars = get_body(planetname, cur_time)
flags = ''
# Are we starting or stopping retrograde?
if ((mars.ra == last_RA)
or (mars.ra < last_RA and not self.retrograding)
or (mars.ra > last_RA and self.retrograding)):
# Are we still in coarse mode? If so, jump back
# in time a few days and go to fine mode.
if timeslice == coarsemode:
print("Switching to fine mode on", cur_time)
print(" RA", mars.ra.hour, ", dec",
mars.dec.degree)
timeslice = finemode
cur_time -= TimeDelta(EXTRA_DAYS, format='jd')
continue
# We're in fine mode. Record dates when the planet
# starts or ends retrograde, hits opposition or makes
# its closest approach.
if self.retrograding:
flags += END_RETROGRADE
# Don't consider this the actual end of retrograde
# unless we're already past opposition.
# There are potentially a lot of false retrogrades.
# We can get them from parallax if we calculate
# Mars' position from a specific earth location;
# but even if we don't, pyastro gives us a lot
# of false little retrogrades and I don't know why.
if opptime:
retro_end = cur_time
else:
flags += START_RETROGRADE
retro_start = cur_time
if mars.ra == last_RA:
flags += STATIONARY
self.retrograding = not self.retrograding
# Calculate elongation to find the opposition time:
sun = get_body('sun', cur_time)
elongation = (mars.ra - sun.ra).degree
# print(cur_time, "\n RA",
# mars.ra.hour, "dec", mars.dec.degree,
# "elongation", elongation)
if last_elong > 180. and elongation <= 180.:
if timeslice == superfinemode:
flags += OPPOSITION
opptime = cur_time
timeslice = finemode
print("Opposition on", cur_time,
", switching back to fine")
# XXX it would be nice not to go back to finemode
# until after we've found closest approach.
# But astropy randomly finds a closest approach
# date weeks before the actual closest approach,
# at the start of retrograde.
else:
# Looks like opposition. But let's go back a day and
# get a finer view of the time.
print("Switching to superfine mode on", cur_time)
timeslice = superfinemode
cur_time -= TimeDelta(1, format='jd')
if mars.distance >= last_dist and pre_closest:
flags += CLOSEST_APPROACH
# self.find_parallax(cur_time)
pre_closest = False
elif mars.distance < last_dist: # receding
pre_closest = True
if flags or self.save_all_points:
self.planettrack.append([
cur_time.datetime, mars.ra.radian, mars.dec.radian,
mars.distance.km, flags
])
last_RA = mars.ra
last_dist = mars.distance
last_elong = elongation
# If we've seen the opposition as well as retro_start and retro_end
# then we're done. Switch back to coarse mode and record a
# few more days.
if timeslice == finemode and retro_start and retro_end and opptime:
timeslice = coarsemode
end_time = cur_time + TimeDelta(EXTRA_DAYS, format='jd')
# We're done calculating all the points.
# Now calculate the retrograde midpoint, if we have both start and end.
if retro_start and retro_end:
mid_retro_date = retro_start + (retro_end - retro_start) / 2
mars = get_body(planetname, mid_retro_date)
# Insert that into our planettrack list:
for i, point in enumerate(self.planettrack):
if point[IDATE] == mid_retro_date:
point[IFLAGS] += MIDPOINT_RETRO
break
elif point[IDATE] > mid_retro_date:
self.planettrack.insert(i, [
mid_retro_date.datetime, mars.ra.radian,
mars.dec.radian, mars.distance.km, MIDPOINT_RETRO
])
# We've just changed a list in the middle of looping
# over that list, but it's okay because we're breaking out.
break
else:
print("don't have both retro start and end")
# Now print what we found.
print("%20s %-19s %-11s %-10s %s" %
('', 'Date', 'RA', 'Dec', 'Dist (mi)'))
for point in self.planettrack:
if point[IFLAGS]:
# print("%20s %-19s %-11s %-10s %d" % \
# (self.flags_to_string(point[4]), str(point[0]),
# point[1], point[2],
# point[3] * 9.2956e7))
print("%20s %-19s %-11.7f %-10.7f %d" % \
(self.flags_to_string(point[IFLAGS]), str(point[IDATE]),
self.rads_to_hours(point[IRA]),
self.rads_to_degrees(point[IDEC]),
point[IDIST] / 1.609344))
