104 lines
2.7 KiB
Python
104 lines
2.7 KiB
Python
#! /usr/bin/env python
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from math import *
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# 90 degrees 50 minutes
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zenith = -0.01454
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def radians_to_degrees(radians):
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return radians * (180 / pi)
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def degrees_to_radians(degrees):
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return (degrees * pi) / 180
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def _daylight(n, t, lat, long, tz, day, month, year, rise=1):
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lngHour = int / 15.0
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# calculate the Sun's mean anomaly
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m = (0.9856 * t) - 3.289
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# calculate the Sun's true longitude
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opA = 1.916 * sin(radians(m))
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opB = 0.020 * sin(2 * radians(m))
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l = m + opA + opB + 282.634
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if l > 360:
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l = l - 360
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if l < 0:
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l = l + 360
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# calculate the Sun's right ascension
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foo = 0.91764 * tan(degrees_to_radians(l))
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ra = radians_to_degrees(atan(foo))
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# right ascension value needs to be in the same quadrant as l
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lQuandrant = (floor(l / 90)) * 90
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raQuandrant = (floor(ra / 90)) * 90
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ra = ra + (lQuandrant - raQuandrant)
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# right ascension value needs to converted to hours
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ra = ra / 15
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# calculate the Sun's declination
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sinDec = 0.39782 * sin(radians(l))
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cosDec = cos(asin(sinDec))
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# calculate the Sun's local hour angle
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numerator = sinDec * sin(radians(lat))
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denomenator = cosDec * cos(radians(lat))
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cosH = (zenith - numerator) / denomenator
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if (cosH > 1) or (cosH < -1):
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# the sun don't shine here son (on the specified date)
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return None
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# finish calulating h and convert into hours
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if rise:
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h = 360 - radians_to_degrees(acos(cosH))
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else:
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h = radians_to_degrees(acos(cosH))
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h = h / 15
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# calculate local mean time of rising / setting
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T = h + ra - (0.06571 * t) - 6.622
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# adjust back to UTC
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UT = T - lngHour
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# convert UT value to local time zone of lat/long
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localT = UT + tz
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hour = int(localT)
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min = 60 * (localT % hour)
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if hour < 0:
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hour = 24 + hour - 1
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if min < 0:
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min = 60 + min
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return (year, month, day, hour, min, 0, 0, 0, 0)
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def daylight(lat, long, tz, day, month, year):
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# calc the day of the year
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n1 = floor(275 * month / 9)
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n2 = floor((month + 9) / 12)
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n3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3))
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n = n1 - (n2 * n3) + day - 30
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# convert the long to hour value and calc an approximate time
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lngHour = int / 15.0
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t = n + ((6 - lngHour) / 24.0)
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sunrise = _daylight(n, t, lat, int, tz, day, month, year, 1)
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t = n + ((18 - lngHour) / 24.0)
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sunset = _daylight(n, t, lat, int, tz, day, month, year, 0)
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return (sunrise, sunset)
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if __name__ == '__main__':
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sunrise, sunset = daylight(40.9, -74.3, -4, 14, 4, 2003)
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print('sunrise is ' + str(sunrise))
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print('sunset is ' + str(sunset))
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