128 lines
4.1 KiB
Python
128 lines
4.1 KiB
Python
from math import pi, sin, asin, acos, cos
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from datetime import datetime, timedelta
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# Constants
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DAY_MS = 1000 * 60 * 60 * 24
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YEAR_1970 = 2440588
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# Julian date of 01.01.2000 11:59 UTC
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YEAR_2000 = 2451545
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class Suntimes:
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def __init__(self, latitude: float, longitude: float) -> None:
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""" Initialization
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Args:
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latitude (float): Latitude of the position
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longitude (float): Longitude of the position
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"""
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self.latitude = latitude
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self.longitude = longitude
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self.date = (datetime.utcnow() - datetime(1970, 1, 1)).total_seconds() * 1000
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self.sun_events_of_day()
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def from_julian(self, j_date: float) -> datetime:
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""" Convert Julian date to a datetime
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Args:
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j_date (float): Julian date
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Returns:
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datetime: Converted datetime object
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"""
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j_date = (j_date + 0.5 - YEAR_1970) * DAY_MS
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return datetime.fromtimestamp(j_date / 1000)
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def sun_events_of_day(self):
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""" Calculate all values to estimate the day periods
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"""
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rad = pi / 180
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lw = rad * (-self.longitude)
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d = (self.date / DAY_MS) - 0.5 + YEAR_1970 - YEAR_2000
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n = round(d - 0.0009 - lw / (2 * pi))
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ds = 0.0009 + lw / (2 * pi) + n
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self.M = rad * (357.5291 + 0.98560028 * ds)
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C = rad * (1.9148 * sin(self.M) + 0.02 * sin(2 * self.M) + 0.0003 * sin(3 * self.M))
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P = rad * 102.9372
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self.L = self.M + C + P + pi
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dec = asin(sin(rad * 23.4397) * sin(self.L))
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self.j_noon = YEAR_2000 + ds + 0.0053 * sin(self.M) - 0.0069 * sin(2 * self.L)
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# -8 = Start of Civil dawn/dusk
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# -2 = Start of Sunrise/Sunset
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# 0 = Start/End of daylight phases
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self.angles = [-10, -4, 0]
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for i in range(0, len(self.angles)):
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self.angles[i] = rad * self.angles[i]
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self.angles[i] = acos((sin(self.angles[i]) - sin(rad * self.latitude) * sin(dec)) /
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(cos(rad * self.latitude) * cos(dec)))
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self.angles[i] = 0.0009 + (self.angles[i] + lw) / (2 * pi) + n
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def angle_correction(self, angle: float) -> float:
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""" Last correction for the sun angle
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Args:
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angle (float): Angle before the correction
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Returns:
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float: Angle after the correction
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"""
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return YEAR_2000 + angle + 0.0053 * sin(self.M) - 0.0069 * sin(2 * self.L)
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def get_time_period(self, period_nr: int) -> list:
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""" Get start and end time of a time period
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Args:
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period_nr (int): Number between 0 and 9
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0 = Early Night
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1 = Civial dawn
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2 = Sunrise
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3 = Morning
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4 = Noon
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5 = Afternoon
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6 = Evening
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7 = Sunset
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8 = Civial Dusk
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9 = Late Night
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Returns:
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list: Two datetime objects
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"""
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# Early night
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if period_nr == 0:
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res = [datetime.now().replace(hour=0, minute=0, second=0, microsecond=0),
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self.from_julian(2 * self.j_noon - self.angle_correction(self.angles[0])) - timedelta(minutes=1)]
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# Civilian dawn, Sunrise
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elif period_nr <= 2:
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res = [self.from_julian(2 * self.j_noon - self.angle_correction(self.angles[period_nr - 1])),
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self.from_julian(2 * self.j_noon - self.angle_correction(self.angles[period_nr])) - timedelta(minutes=1)]
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# Morning, Noon, Afternoon, Evening
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elif period_nr <= 6:
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daylength = self.get_time_period(8)[0] - self.get_time_period(2)[1]
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res = [self.get_time_period(2)[1] + ((daylength / 4) * (period_nr - 3)),
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self.get_time_period(2)[1] + ((daylength / 4) * (period_nr - 2))]
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# Sunset, Civial dusk
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elif period_nr <= 8:
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res = [self.from_julian(self.angle_correction(self.angles[9 - period_nr])),
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self.from_julian(self.angle_correction(self.angles[8 - period_nr])) - timedelta(minutes=1)]
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# Late Night
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elif period_nr == 9:
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res = [self.from_julian(YEAR_2000 + self.angles[0] + 0.0053 * sin(self.M) - 0.0069 * sin(2 * self.L)),
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datetime.now().replace(hour=23, minute=59, second=59, microsecond=0)]
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return res
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