def test_timescale_with_old_fashioned_leap_second_table():
# Skyfield no longer uses the awkward old-style leap second table,
# written before I knew better, with inf's on both ends; but in case
# any users built such tables and supplied them manually:
delta_t = array([[2442046.5005113888], [44.4782581]])
leap_dates = array([-inf, 2441317.5, 2441499.5, 2441683.5, 2442048.5, inf])
leap_offsets = array([10, 10, 10, 11, 12, 13])
ts = Timescale(delta_t, leap_dates, leap_offsets)
t = ts.tai(1973, 1, 1, 0, 0, [11, 12])
assert t.utc.T.tolist() == [
[1972, 12, 31, 23, 59, 60],
[1973, 1, 1, 0, 0, 0],
]
# The offset prior to the first leap second should be +10.
t = ts.tai(1970, 1, 1)
assert t.utc == (1969, 12, 31, 23, 59, 50)
def test_build_timescale_arrays():
mjd = array([42046.00, 42047.00, 42048.00, 42049.00])
dut1 = array([-0.2942581, -0.2971424, 0.6999438, 0.6970539])
daily_tt, daily_delta_t, leap_dates, leap_offsets = (
iers.build_timescale_arrays(mjd, dut1))
assert list(daily_tt) == [
2442046.5005113888, 2442047.5005113888, 2442048.500522963,
2442049.500522963
]
assert list(daily_delta_t) == [
44.4782581, 44.4811424, 44.4840562, 44.4869461
]
assert list(leap_dates) == [2441499.5, 2441683.5, 2442048.5]
assert list(leap_offsets) == [11, 12, 13]
ts = Timescale((daily_tt, daily_delta_t), leap_dates, leap_offsets)
t = ts.tai(1973, 1, 1, 0, 0, [11, 12])
assert t.utc.T.tolist() == [
[1972, 12, 31, 23, 59, 60],
[1973, 1, 1, 0, 0, 0],
]
def test_iss_altitude_computed_with_gcrs(iss_transit):
dt, their_altitude = iss_transit
cst = timedelta(hours=-6) #, minutes=1)
dt = dt - cst
jd = Timescale(delta_t=67.2091).utc(dt)
lines = iss_tle.splitlines()
s = EarthSatellite(lines, None)
lake_zurich = api.Topos(latitude_degrees=42.2, longitude_degrees=-88.1)
alt, az, d = lake_zurich.at(jd).observe(s).altaz()
print(dt, their_altitude, alt.degrees, their_altitude - alt.degrees)
assert abs(alt.degrees - their_altitude) < 2.5 # TODO: tighten this up?
def test_iss_altitude_computed_with_bcrs(iss_transit):
dt, their_altitude = iss_transit
cst = timedelta(hours=-6) #, minutes=1)
dt = dt - cst
jd = Timescale(delta_t=67.2091).utc(dt)
lines = iss_tle.splitlines()
s = EarthSatellite(lines, None)
earth = api.load('de421.bsp')['earth']
lake_zurich = earth.topos(latitude_degrees=42.2, longitude_degrees=-88.1)
# Compute using Solar System coordinates:
alt, az, d = lake_zurich.at(jd).observe(s).altaz()
print(dt, their_altitude, alt.degrees, their_altitude - alt.degrees)
assert abs(alt.degrees - their_altitude) < 2.5 # TODO: tighten this up?
def string(self, timescale: Timescale):
if self.inner is None:
return ""
t = timescale.tt_jd(self.inner + 3 / 24)
return "{}-{:02d}-{:02d} {:02d}:{:02d}".format(*t.ut1_calendar())
def ts():
yield Timescale()
def test_JulianDate_init(time_parameter, time_value):
method = getattr(Timescale(), time_parameter)
jd = method(time_value)
assert getattr(jd, time_parameter) == 2441700.56640625