def _xyzRov(self, obs):
"""
calculates the heliocentric position of a roving observer at
UTC JD in equatorial cartesian coordinates.
Payne: This does *NOT* have an equivalent in MPCU.Observatory.
"""
key = ('247', obs.jdutc)
try:
return self.cache[key]
except KeyError:
pass
leaps = self.leapsec.getLeapSeconds(obs.jdutc)
delta_t = 32.184 + leaps
jd_tt = obs.jdutc + delta_t / (24.0 * 60 * 60)
e = MPCU.getEarthPosition(jd_tt) # Might need to switch to tdb
observer = novas.make_observer_on_surface(obs.lat, obs.lon, obs.alt, 5,
990)
# posvel returns GCRS
o, _ = novas.geo_posvel(jd_tt, delta_t, observer)
# add ICRS and GCRS?
hc = (e[0] + o[0], e[1] + o[1], e[2] + o[2])
self.cache[key] = hc
return hc
def V_LSR(RA, dec, dss, timedate):
"""
Computes the velocity of the local standard of rest w.r.t. the observer
@param ra : J2000 right ascension as a float or as "12h34m56.78s"
@type ra : float or str
@param dec : J2000 declination as a float or as "-12d34m56.78s"
@type dec : float or str
@param observer : DSN station
@type observer : int
@param timedate : date/time of the observation
@type timedate : datetime object
"""
logger.debug("V_LSR: entered with coord types %s and %s", type(RA),
type(dec))
if type(RA) == str and type(dec) == str:
skypos = coord.SkyCoord(RA, dec, unit=(u.hourangle, u.deg))
elif type(RA) == float and type(dec) == float:
skypos = coord.SkyCoord(RA * u.hour, dec * u.degree)
else:
raise RuntimeError(RA, dec, "cannot be parsed")
logger.debug("V_LSR: sky pos: %s", skypos)
ra2000, dec2000 = skypos.ra.hour, skypos.dec.deg
logger.debug("V_LSR: J2000 coordinates are %f, %f", ra2000, dec2000)
sourcename = "%5.2f%+5.2f" % (ra2000, dec2000)
cat_entry = novas.make_cat_entry(sourcename, "", 0, ra2000, dec2000, 0, 0,
0, 0)
source = novas.make_object(2, 0, sourcename, cat_entry)
station = Astronomy.DSN_coordinates.DSS(dss)
logger.debug("V_LSR: station lat=%f", station.lat * 180 / math.pi)
logger.debug("V_LSR: station long=%f", station.lon * 180 / math.pi)
if station.long > math.pi:
longitude = station.long - 2 * math.pi
elif station.long < math.pi:
longitude = station.long + 2 * math.pi
else:
longitude = station.long
observer = novas.make_observer_on_surface(station.lat * 180 / math.pi,
longitude * 180 / math.pi,
station.elev, 0, 0)
jd = novas.julian_date(timedate.year, timedate.month, timedate.day,
timedate.hour + timedate.minute / 60.)
mjd = DatesTimes.MJD(timedate.year, timedate.month, timedate.day)
earth = novas.make_object(0, 3, 'Earth', None)
urthpos, urthvel = novas.ephemeris((jd, 0), earth, origin=0)
(obspos, obsvel) = novas.geo_posvel(jd, 0, observer, 0)
totvel = tuple(numpy.array(urthvel) + numpy.array(obsvel))
(srcpos, srcvel) = novas.starvectors(cat_entry)
V = novas.rad_vel(source, srcpos, srcvel, totvel, 0, 0, 0)
logger.debug("V_LSR: velocity of observer w.r.t. Sun= %.2f", V)
return V + Astronomy.v_sun(mjd, ra2000 / 15., dec2000)
def test_geocentric_position_and_velocity(jd):
observer = c.make_observer_on_surface(45.0, -75.0, 0.0, 10.0, 1010.0)
posu, velu = c.geo_posvel(jd.tt, jd.delta_t, observer)
topos = positionlib.Topos('45 N', '75 W', elevation=0.0,
temperature=10.0, pressure=1010.0)
posv, velv = earthlib.geocentric_position_and_velocity(topos, jd)
epsilon = 1e-6 * meter # 13 to 14 digits of agreement
eq(posu, posv, epsilon)
eq(velu, velv, epsilon)
def test_geocentric_position_and_velocity():
epsilon = 1e-13
delta_t = 0.0
observer = c.make_observer_on_surface(45.0, -75.0, 0.0, 10.0, 1010.0)
pos0, vel0 = c.geo_posvel(T0, delta_t, observer)
posA, velA = c.geo_posvel(TA, delta_t, observer)
topos = coordinates.Topos('75 W', '45 N', elevation=0.0,
temperature=10.0, pressure=1010.0)
jd = JulianDate(tt=[T0, TA], delta_t=delta_t)
posv, velv = earthlib.geocentric_position_and_velocity(topos, jd)
eq(posv.T, [pos0, posA], epsilon)
eq(velv.T, [vel0, velA], epsilon)
def test_github_issue1_limb_angle(self):
# https://github.com/brandon-rhodes/python-novas/pull/1
# The _limb_angle() function was always return zero.
observer = novas.make_observer_on_surface(
latitude, longitude, height, temperature, pressure)
position_observer, velocity_observer = novas.geo_posvel(
jd, delta_t, observer, accuracy)
position_obj = (-10.0, -0.3, 0.0)
limb, nadir = novas.limb_angle(position_obj, position_observer)
self.assertAlmostEqual(limb, -21.7796002325, 12)
self.assertAlmostEqual(nadir, 0.758004441861, 12)
def test_github_issue1_limb_angle(self):
# https://github.com/brandon-rhodes/python-novas/pull/1
# The _limb_angle() function was always return zero.
observer = novas.make_observer_on_surface(latitude, longitude, height,
temperature, pressure)
position_observer, velocity_observer = novas.geo_posvel(
jd, delta_t, observer, accuracy)
position_obj = (-10.0, -0.3, 0.0)
limb, nadir = novas.limb_angle(position_obj, position_observer)
self.assertAlmostEqual(limb, -21.7796002325, 12)
self.assertAlmostEqual(nadir, 0.758004441861, 12)
delta_t = tt_tai + leap_second - ut1_utc
#构造不同的儒略日时间变量
jd_utc = novas.julian_date(year, month, day, hour) #utc
jd_ut1 = jd_utc + ut1_utc / 86400.0 #ut1
jd_tt = jd_utc + (leap_second + tt_tai) / 86400.0 #tt
jd = (jd_tt, 0.0)
jd0 = (jd_tt - ta / 86400, 0.0)
#打开de历表
jd_s, jd_e, num = eph_manager.ephem_open()
#太阳和地球构造
sun = novas.make_object(0, 10, 'sun', None)
moon = novas.make_object(0, 11, 'moon', None)
earth = novas.make_object(0, 3, 'earth', None)
#位置构造
location1 = novas.make_on_surface(latitude, longitude, height, 25.0, 1013)
location = novas.make_observer_on_surface(latitude, longitude, height, 25.0,
1013)
#矢量和夹角初始化
O1_S1 = [0.0, 0.0, 0.0] #月球半影锥点到太阳质心矢量坐标
O2_S1 = [0.0, 0.0, 0.0] #月球全影锥点到太阳质心矢量坐标
O1_E = [0.0, 0.0, 0.0] #月球半影锥点到地心距离矢量坐标
O1_T = [0.0, 0.0, 0.0] #月球半影锥点到地球某一点距离矢量坐标
O2_E = [0.0, 0.0, 0.0] #月球全影锥点到地心距离矢量坐标
O2_T = [0.0, 0.0, 0.0] #月球全影锥点到地球某一点距离矢量坐标
O1_M = [0.0, 0.0, 0.0] #月球半影锥点到月心距离矢量坐标
O2_M = [0.0, 0.0, 0.0] #月球全影锥点到月心距离矢量坐标
E_O4 = [0.0, 0.0, 0.0]
#经纬度转为ITRS下坐标
E_T=[re*math.cos(latitude*constants.DEG2RAD)*math.cos(longitude*constants.DEG2RAD),\
re*math.cos(latitude*constants.DEG2RAD)*math.sin(longitude*constants.DEG2RAD),\
re*math.sin(latitude*constants.DEG2RAD)\
]