def new_moon_before(cls, tee):
"""Return the approximate moment of last new moon preceding moment, tee,
close enough to determine zodiacal sign."""
varepsilon = pow(2, -1000)
tau = tee - ((1/360) * cls.lunar_phase(tee) * cls.SYNODIC_MONTH)
return binary_search(tau - 1, min(tee, tau + 1),
lambda l, u: cls.zodiac(l) == cls.zodiac(u) or u - l < varepsilon,
lambda x: cls.lunar_phase(x) < 180)
def moonrise(self, date):
"""Return the standard time of moonrise on fixed, date,
and location, location."""
t = self.universal_from_standard(date)
waning = (Lunar.lunar_phase(t) > 180)
alt = self.observed_lunar_altitude(t)
offset = alt / 360
if waning and (offset > 0):
approx = t + 1 - offset
elif waning:
approx = t - offset
else:
approx = t + (1 / 2) + offset
rise = binary_search(approx - Clock.days_from_hours(3),
approx + Clock.days_from_hours(3),
lambda u, l: ((u - l) < Clock.days_from_hours(1/60)),
lambda x: self.observed_lunar_altitude(x) > 0)
if rise < (t + 1):
return self.standard_from_universal(rise)
raise ValueError()