def __get_relative_prime_meridian(year):
"""
- total progression = 100d42.6 + cumulative prog + leap progs
- cumulative progression: delta(year-2001) * -0d14.31667
- leap progression: (leap years elapsed) * 0d59.0
:param year: observation year
:return: angle of prime meridian
"""
reference_rotation = Angle.from_string("100d42.6")
# cumulative progression: delta(year-2001) * -0d14.31667
annual_gha_decrement = Angle.from_string("-0d14.32")
delta_year = year - Aries.REFERENCE_YEAR
cumulative_progression = Angle.multiply(annual_gha_decrement,
delta_year)
# leap progression: (leap years elapsed) * 0d59.0
daily_rotation = Angle.from_string("0d59.0")
leap_years = math.floor((year - Aries.REFERENCE_YEAR) / 4)
leap_progression = Angle.multiply(daily_rotation, leap_years)
# total progression = 100d42.6 + cumulative prog + leap progs
total_progression = Angle.add(reference_rotation,
cumulative_progression)
total_progression = Angle.add(total_progression, leap_progression)
print("total progression" + total_progression.str)
return total_progression
def get_greenwich_hour_angle(year, month, day, hour, minute, second):
"""
= relative_prime_meridian + earth rotation
:param year:
:param month:
:param day:
:param hour:
:param minute:
:param second:
:return:
"""
reference_datetime_str = str(year) + ",01,01,00,00,00"
observation_datetime_str = str(year) + ',' + str(month) + ',' + str(
day) + ','
observation_datetime_str += str(hour) + ',' + str(minute) + ',' + str(
second)
observation_datetime = datetime.strptime(observation_datetime_str,
'%Y,%m,%d,%H,%M,%S')
reference_datetime = datetime.strptime(reference_datetime_str,
'%Y,%m,%d,%H,%M,%S')
elapsed_sed_since_ref = (observation_datetime -
reference_datetime).total_seconds()
relative_pm = Aries.__get_relative_prime_meridian(year)
earth_rotation = Aries.__get_earth_rotation_since_observation(
elapsed_sed_since_ref)
print("relative_pm" + relative_pm.str)
print("earth_rotation" + earth_rotation.str)
return Angle.add(relative_pm, earth_rotation)
def test_arithmatic(self):
small_aggle = Angle(60)
big_angle = Angle(320)
total_angle = small_aggle.add(big_angle)
self.assertEqual(20, total_angle.degrees,
'Adding agle with wrap-around')
