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authorMattias Andrée <maandree@kth.se>2021-02-19 22:10:26 +0100
committerMattias Andrée <maandree@kth.se>2021-02-19 22:10:26 +0100
commitec7baa81e8fd4bec924d6adf3ee880af621a10ba (patch)
tree700434a1a65c55584dff270ed45e4bdfd46f6ab3 /src
parentAdd blue hour (diff)
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Imrpove makefile and flatten the hier a bit
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to 'src')
-rw-r--r--src/solar_python.py846
1 files changed, 0 insertions, 846 deletions
diff --git a/src/solar_python.py b/src/solar_python.py
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--- a/src/solar_python.py
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@@ -1,846 +0,0 @@
-# solar-python — Solar data calculation and prediction library for Python
-# Copyright © 2014, 2015 Mattias Andrée (maandree@member.fsf.org)
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU Affero General Public License for more details.
-#
-# You should have received a copy of the GNU Affero General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-
-
-SOLAR_APPARENT_RADIUS = 32.0 / 60.0
-'''
-:float Approximate apparent size of the Sun in degrees
-'''
-
-
-SOLAR_ELEVATION_PRESUNSET_POSTSUNRISE = 32.0 / 60.0
-'''
-:float The Sun's elevation the beginning of sunset and
- end of sunrise, measured in degrees
-'''
-
-SOLAR_ELEVATION_SUNSET_SUNRISE = -32.0 / 60.0
-'''
-:float The Sun's elevation the (end of) at sunset and
- (beginning of) sunrise, measured in degrees
-'''
-
-SOLAR_ELEVATION_CIVIL_DUSK_DAWN = -6.0
-'''
-:float The Sun's elevation at civil dusk and civil
- dawn, measured in degrees
-'''
-
-SOLAR_ELEVATION_NAUTICAL_DUSK_DAWN = -12.0
-'''
-:float The Sun's elevation at nautical dusk and
- nautical dawn, measured in degrees
-'''
-
-SOLAR_ELEVATION_AMATEUR_ASTRONOMICAL_DUSK_DAWN = -15.0
-'''
-:float The Sun's elevation at amateur astronomical dusk
- and amateur astronomical dawn, measured in degrees
-'''
-
-SOLAR_ELEVATION_ASTRONOMICAL_DUSK_DAWN = -18.0
-'''
-:float The Sun's elevation at astronomical dusk
- and astronomical dawn, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_TWILIGHT = (-18.0, 0.0)
-'''
-:(float, float) The Sun's lowest and highest elevation during
- all periods of twilight, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_CIVIL_TWILIGHT = (-6.0, SOLAR_ELEVATION_SUNSET_SUNRISE)
-'''
-:(float, float) The Sun's lowest and highest elevation
- during civil twilight, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_NAUTICAL_TWILIGHT = (-12.0, SOLAR_ELEVATION_SUNSET_SUNRISE)
-'''
-:(float, float) The Sun's lowest and highest elevation
- during nautical twilight, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_ASTRONOMICAL_TWILIGHT = (-18.0, SOLAR_ELEVATION_SUNSET_SUNRISE)
-'''
-:(float, float) The Sun's lowest and highest elevation during
- astronomical twilight, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_AMATEUR_ASTRONOMICAL_TWILIGHT = (-18.0, -15.0)
-'''
-:(float, float) The Sun's lowest and highest elevation during
- amateur astronomical twilight, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_GOLDEN_HOUR = (-4.0, 6.0)
-'''
-:(float, float) The Sun's lowest and highest elevation during
- the golden "hour" (also known as magic hour),
- measured in degrees. These elevations are
- approximate.
-'''
-
-SOLAR_ELEVATION_RANGE_BLUE_HOUR = (-6.0, -4.0)
-'''
-:(float, float) The Sun's lowest and highest elevation during
- the blue "hour", measured in degrees. These
- elevations are approximate.
-'''
-
-
-
-# The following functions are used to calculate the result for `sun`
-# (most of them) but could be used for anything else. There name is
-# should tell you enough, `t` (and `noon`) is in Julian Centuries
-# except for in the convertion methods.
-
-
-def julian_day_to_epoch(t):
- '''
- Converts a Julian Day timestamp to a POSIX time timestamp
-
- @param t:float The time in Julian Days
- @return :float The time in POSIX time
- '''
- return (t - 2440587.5) * 86400.0
-
-
-def epoch_to_julian_day(t):
- '''
- Converts a POSIX time timestamp to a Julian Day timestamp
-
- @param t:float The time in POSIX time
- @return :float The time in Julian Days
- '''
- return t / 86400.0 + 2440587.5
-
-
-def julian_day_to_julian_centuries(t):
- '''
- Converts a Julian Day timestamp to a Julian Centuries timestamp
-
- @param t:float The time in Julian Days
- @return :float The time in Julian Centuries
- '''
- return (t - 2451545.0) / 36525.0
-
-
-def julian_centuries_to_julian_day(t):
- '''
- Converts a Julian Centuries timestamp to a Julian Day timestamp
-
- @param t:float The time in Julian Centuries
- @return :float The time in Julian Days
- '''
- return t * 36525.0 + 2451545.0
-
-
-def epoch_to_julian_centuries(t):
- '''
- Converts a POSIX time timestamp to a Julian Centuries timestamp
-
- @param t:float The time in POSIX time
- @return :float The time in Julian Centuries
- '''
- return julian_day_to_julian_centuries(epoch_to_julian_day(t))
-
-
-def julian_centuries_to_epoch(t):
- '''
- Converts a Julian Centuries timestamp to a POSIX time timestamp
-
- @param t:float The time in Julian Centuries
- @return :float The time in POSIX time
- '''
- return julian_day_to_epoch(julian_centuries_to_julian_day(t))
-
-
-def epoch():
- '''
- Get current POSIX time
-
- @return :float The current POSIX time
- '''
- import time
- return time.time()
-
-
-def julian_day():
- '''
- Get current Julian Day time
-
- @return :float The current Julian Day time
- '''
- return epoch_to_julian_day(epoch())
-
-
-def julian_centuries():
- '''
- Get current Julian Centuries time (100 Julian days since J2000)
-
- @return :float The current Julian Centuries time
- '''
- return epoch_to_julian_centuries(epoch())
-
-
-def radians(deg):
- '''
- Convert an angle from degrees to radians
-
- @param deg:float The angle in degrees
- @return :float The angle in radians
- '''
- import math
- return deg * math.pi / 180
-
-
-def degrees(rad):
- '''
- Convert an angle from radians to degrees
-
- @param rad:float The angle in radians
- @return :float The angle in degrees
- '''
- import math
- return rad * 180 / math.pi
-
-
-def sun_geometric_mean_longitude(t):
- '''
- Calculates the Sun's geometric mean longitude
-
- @param t:float The time in Julian Centuries
- @return :float The Sun's geometric mean longitude in radians
- '''
- return radians((0.0003032 * t ** 2 + 36000.76983 * t + 280.46646) % 360)
- # CANNIBALISERS:
- # The result of this function should always be positive, this
- # means that after division modulo 360 but before `radians`,
- # you will need to add 360 if the value is negative. This can
- # only happen if `t` is negative, which can only happen for date
- # times before 2000-(01)Jan-01 12:00:00 UTC par division modulo
- # implementations with the signess of at least the left operand.
- # More precively, it happens between circa 1970-(01)Jan-11
- # 16:09:02 UTC and circa 374702470660351740 seconds before
- # January 1, 1970 00:00 UTC, which is so far back in time
- # it cannot be reliable pinned down to the right year, but it
- # is without a shadow of a doubt looooong before the Earth
- # was formed, is right up there with the age of the Milky Way
- # and the universe itself.
-
-
-def sun_geometric_mean_anomaly(t):
- '''
- Calculates the Sun's geometric mean anomaly
-
- @param t:float The time in Julian Centuries
- @return :float The Sun's geometric mean anomaly in radians
- '''
- return radians(-0.0001537 * t ** 2 + 35999.05029 * t + 357.52911)
-
-
-def earth_orbit_eccentricity(t):
- '''
- Calculates the Earth's orbit eccentricity
-
- @param t:float The time in Julian Centuries
- @return :float The Earth's orbit eccentricity
- '''
- return -0.0000001267 * t ** 2 - 0.000042037 * t + 0.016708634
-
-
-def sun_equation_of_centre(t):
- '''
- Calculates the Sun's equation of the centre, the difference between
- the true anomaly and the mean anomaly
-
- @param t:float The time in Julian Centuries
- @return :float The Sun's equation of the centre, in radians
- '''
- import math
- a = sun_geometric_mean_anomaly(t)
- rc = math.sin(1 * a) * (-0.000014 * t ** 2 - 0.004817 * t + 1.914602)
- rc += math.sin(2 * a) * (-0.000101 * t + 0.019993)
- rc += math.sin(3 * a) * 0.000289
- return radians(rc)
-
-
-def sun_real_longitude(t):
- '''
- Calculates the Sun's real longitudinal position
-
- @param t:float The time in Julian Centuries
- @return :float The longitude, in radians
- '''
- rc = sun_geometric_mean_longitude(t)
- return rc + sun_equation_of_centre(t)
-
-
-def sun_apparent_longitude(t):
- '''
- Calculates the Sun's apparent longitudinal position
-
- @param t:float The time in Julian Centuries
- @return :float The longitude, in radians
- '''
- import math
- rc = degrees(sun_real_longitude(t)) - 0.00569
- rc -= 0.00478 * math.sin(radians(-1934.136 * t + 125.04))
- return radians(rc)
-
-
-def mean_ecliptic_obliquity(t):
- '''
- Calculates the mean ecliptic obliquity of the Sun's
- apparent motion without variation correction
-
- @param t:float The time in Julian Centuries
- @return :float The uncorrected mean obliquity, in radians
- '''
- rc = 0.001813 * t ** 3 - 0.00059 * t ** 2 - 46.815 * t + 21.448
- rc = 26 + rc / 60
- rc = 23 + rc / 60
- return radians(rc)
-
-
-def corrected_mean_ecliptic_obliquity(t):
- '''
- Calculates the mean ecliptic obliquity of the Sun's
- apparent motion with variation correction
-
- @param t:float The time in Julian Centuries
- @return :float The mean obliquity, in radians
- '''
- import math
- rc = -1934.136 * t + 125.04
- rc = 0.00256 * math.cos(radians(rc))
- rc += degrees(mean_ecliptic_obliquity(t))
- return radians(rc)
-
-
-def solar_declination(t):
- '''
- Calculates the Sun's declination
-
- @param t:float The time in Julian Centuries
- @return :float The Sun's declination, in radians
- '''
- import math
- rc = math.sin(corrected_mean_ecliptic_obliquity(t))
- rc *= math.sin(sun_apparent_longitude(t))
- return math.asin(rc)
-
-
-def equation_of_time(t):
- '''
- Calculates the equation of time, the discrepancy
- between apparent and mean solar time
-
- @param t:float The time in Julian Centuries
- @return :float The equation of time, in degrees
- '''
- import math
- l = sun_geometric_mean_longitude(t)
- e = earth_orbit_eccentricity(t)
- m = sun_geometric_mean_anomaly(t)
- y = corrected_mean_ecliptic_obliquity(t)
- y = math.tan(y / 2) ** 2
- rc = y * math.sin(2 * l)
- rc += (4 * y * math.cos(2 * l) - 2) * e * math.sin(m)
- rc -= 0.5 * y ** 2 * math.sin(4 * l)
- rc -= 1.25 * e ** 2 * math.sin(2 * m)
- return 4 * degrees(rc)
-
-
-def hour_angle_from_elevation(latitude, declination, elevation):
- '''
- Calculates the solar hour angle from the Sun's elevation
-
- @param longitude:float The longitude in degrees eastwards
- from Greenwich, negative for westwards
- @param declination:float The declination, in radians
- @param elevation:float The Sun's elevation, in radians
- @return :float The solar hour angle, in radians
- '''
- import math
- if elevation == 0:
- return 0
- rc = math.cos(abs(elevation))
- rc -= math.sin(radians(latitude)) * math.sin(declination)
- rc /= math.cos(radians(latitude)) * math.cos(declination)
- rc = math.acos(rc)
- return -rc if (rc < 0) == (elevation < 0) else rc
-
-
-def elevation_from_hour_angle(latitude, declination, hour_angle):
- '''
- Calculates the Sun's elevation from the solar hour angle
-
- @param longitude:float The longitude in degrees eastwards
- from Greenwich, negative for westwards
- @param declination:float The declination, in radians
- @param hour_angle:float The solar hour angle, in radians
- @return :float The Sun's elevation, in radians
- '''
- import math
- rc = math.cos(radians(latitude))
- rc *= math.cos(hour_angle) * math.cos(declination)
- rc += math.sin(radians(latitude)) * math.sin(declination)
- return math.asin(rc)
-
-
-def time_of_solar_noon(t, longitude):
- '''
- Calculates the time of the closest solar noon
-
- @param t:float A time close to the sought time,
- in Julian Centuries
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @return :float The time, in Julian Centuries,
- of the closest solar noon
- '''
- t, rc = julian_centuries_to_julian_day(t), longitude
- for (k, m) in ((-360, 0), (1440, -0.5)):
- rc = julian_day_to_julian_centuries(t + m + rc / k)
- rc = 720 - 4 * longitude - equation_of_time(rc)
- return rc
-
-
-def time_of_solar_elevation(t, noon, latitude, longitude, elevation):
- '''
- Calculates the time the Sun has a specified apparent
- elevation at a geographical position
-
- @param t:float A time close to the sought time,
- in Julian Centuries
- @param noon:float The time of the closest solar noon
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param elevation:float The solar elevation, in radians
- @return :float The time, in Julian Centuries,
- of the specified elevation
- '''
- rc = noon
- rc, et = solar_declination(rc), equation_of_time(rc)
- rc = hour_angle_from_elevation(latitude, rc, elevation)
- rc = 720 - 4 * (longitude + degrees(rc)) - et
-
- rc = julian_day_to_julian_centuries(julian_centuries_to_julian_day(t) + rc / 1440)
- rc, et = solar_declination(rc), equation_of_time(rc)
- rc = hour_angle_from_elevation(latitude, rc, elevation)
- rc = 720 - 4 * (longitude + degrees(rc)) - et
- return rc
-
-
-def solar_elevation_from_time(t, latitude, longitude):
- '''
- Calculates the Sun's elevation as apparent
- from a geographical position
-
- @param t:float The time in Julian Centuries
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @return :float The Sun's apparent elevation at the specified
- time as seen from the specified position,
- measured in radians
- '''
- rc = julian_centuries_to_julian_day(t)
- rc = (rc - float(int(rc + 0.5)) - 0.5) * 1440
- rc = 720 - rc - equation_of_time(t)
- rc = radians(rc / 4 - longitude)
- return elevation_from_hour_angle(latitude, solar_declination(t), rc)
-
-
-def solar_elevation(latitude, longitude, t = None):
- '''
- Calculates the Sun's elevation as apparent
- from a geographical position
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float The Sun's apparent elevation at the specified
- time as seen from the specified position,
- measured in degrees
- '''
- rc = julian_centuries() if t is None else t
- rc = solar_elevation_from_time(rc, latitude, longitude)
- return degrees(rc)
-
-
-
-def have_sunrise_and_sunset(latitude, t = None):
- '''
- Determine whether solar declination currently is
- so that there can be sunrises and sunsets. If not,
- you either have 24-hour daytime or 24-hour nighttime.
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return Whether there can be sunrises and
- sunsets where you are located
- '''
- t = julian_centuries() if t is None else t
- d = degrees(solar_declination(t))
- ## Convert everything to the Northern hemisphere
- latitude = abs(latitude)
- if d >= 0:
- ## Northern summer
- return -90 + d < latitude < 90 - d
- else:
- ## Northern winter
- return -90 - d < latitude < 90 + d
-
-
-def is_summer(latitude, t = None):
- '''
- Determine whether it is summer
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return Whether it is summer on the hemisphere
- you are located on
- '''
- t = julian_centuries() if t is None else t
- d = solar_declination(t)
- return (d > 0) == (latitude > 0)
-
-
-def is_winter(latitude, t = None):
- '''
- Determine whether it is winter
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return Whether it is winter on the hemisphere
- you are located on
- '''
- t = julian_centuries() if t is None else t
- d = solar_declination(t)
- return not ((d > 0) == (latitude > 0))
-
-
-
-def solar_prediction(delta, requested, fun, epsilon = 0.000001, span = 0.01, t = None):
- '''
- Predict the time point of the next or previous
- time an arbitrary condition is meet
-
- @param delta:float Iteration step size, negative for past
- event, positive for future event
- @param requested:float The value returned by `fun` for which to
- calculate the time point of occurrence
- @param fun:(t:float)→float Function that calculate the data of interest
- @param epsilon:float The tolerance for the result
- @param span:float The number of Julian Centuries (0,01 for
- one year) to restrict the search to
- @param t:float? The time in Julian Centuries, `None` for
- the current time
- @return :float? The calculated time point, `None` if none
- were found within the specified time span
- '''
- fun_ = lambda t : fun(t) - requested
- t = julian_centuries() if t is None else t
- t1 = t2 = t
- v1 = v0 = fun_(t)
-
- # Predicate time point to within a small time span
- while True:
- if abs(t2 - t) > span:
- return None
- t2 += delta
- v2 = fun_(t2)
- if (v1 <= 0 <= v2) or ((0 >= v1 >= v2) and (0 <= v0)):
- break
- if (v1 >= 0 >= v2) or ((0 <= v1 <= v2) and (0 >= v0)):
- break
- t1 = t2
- v2 = v1
-
- # Binary search the small time span for the exact time point
- for _itr in range(1000):
- tm = (t1 + t2) / 2
- v1 = fun_(t1)
- v2 = fun_(t2)
- vm = fun_(tm)
- if abs(v1 - v2) < epsilon:
- return tm
- if v1 < v2:
- if 0 < vm:
- t2 = tm
- else:
- t1 = tm
- elif v1 > v2:
- if 0 > vm:
- t2 = tm
- else:
- t1 = tm
- return tm
-
-
-
-def future_past_equinox(delta, t = None):
- '''
- Predict the time point of the next or previous equinox
-
- @param delta:float Iteration step size, negative for
- past event, positive for future event
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float The calculated time point
- '''
- return solar_prediction(delta, 0, solar_declination, t = t)
-
-
-def future_equinox(t = None):
- '''
- Predict the time point of the next equinox
-
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float The calculated time point
- '''
- return future_past_equinox(0.01 / 2000, t)
-
-
-def past_equinox(t = None):
- '''
- Predict the time point of the previous equinox
-
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float The calculated time point
- '''
- return future_past_equinox(0.01 / -2000, t)
-
-
-
-def future_past_solstice(delta, t = None):
- '''
- Predict the time point of the next or previous solstice
-
- @param delta:float Iteration step size, negative for
- past event, positive for future event
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float The calculated time point
- '''
- e = 0.00001
- fun = solar_declination
- dfun = lambda t : (fun(t + e) - fun(t - e)) / (2 * e)
- return solar_prediction(delta, 0, dfun, t = t)
-
-
-def future_solstice(t = None):
- '''
- Predict the time point of the next solstice
-
- @param t:float? The time in Julian Centuries,
- `None` for the current time
- @return :float The calculated time point
- '''
- return future_past_solstice(0.01 / 2000, t)
-
-
-def past_solstice(t = None):
- '''
- Predict the time point of the previous solstice
-
- @param t:float? The time in Julian Centuries,
- `None` for the current time
- @return :float The calculated time point
- '''
- return future_past_solstice(0.01 / -2000, t)
-
-
-
-def future_past_elevation(delta, latitude, longitude, elevation, t = None):
- '''
- Predict the time point of the next or previous time
- the Sun reaches or reached a specific elevation
-
- @param delta:float Iteration step size, negative for past
- event, positive for future event
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param elevation:float The elevation of interest
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float? The calculated time point, `None` if
- none were found within a year
- '''
- fun = lambda t : solar_elevation(latitude, longitude, t)
- return solar_prediction(delta, elevation, fun, t = t)
-
-
-def future_elevation(latitude, longitude, elevation, t = None):
- '''
- Predict the time point of the next time the Sun
- reaches a specific elevation
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param elevation:float The elevation of interest
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float? The calculated time point, `None` if
- none were found within a year
- '''
- return future_past_elevation(0.01 / 2000, latitude, longitude, elevation, t)
-
-
-def past_elevation(latitude, longitude, elevation, t = None):
- '''
- Predict the time point of the previous time the Sun
- reached a specific elevation
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param elevation:float The elevation of interest
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float? The calculated time point, `None` if
- none were found within a year
- '''
- return future_past_elevation(0.01 / -2000, latitude, longitude, elevation, t)
-
-
-
-def future_past_elevation_derivative(delta, latitude, longitude, derivative, t = None):
- '''
- Predict the time point of the next or previous time the
- Sun reaches or reached a specific elevation derivative
-
- @param delta:float Iteration step size, negative for past
- event, positive for future event
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param derivative:float The elevation derivative value of interest
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float? The calculated time point, `None` if
- none were found within a year
- '''
- e = 0.00001
- fun = lambda t : solar_elevation(latitude, longitude, t)
- dfun = lambda t : (fun(t + e) - fun(t - e)) / (2 * e)
- return solar_prediction(delta, derivative, dfun, t = t)
-
-
-def future_elevation_derivative(latitude, longitude, derivative, t = None):
- '''
- Predict the time point of the next time the
- Sun reaches a specific elevation derivative
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param derivative:float The elevation derivative value of interest
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float? The calculated time point, `None` if
- none were found within a year
- '''
- return future_past_elevation_derivative(0.01 / 2000, latitude, longitude, derivative, t)
-
-
-def past_elevation_derivative(latitude, longitude, derivative, t = None):
- '''
- Predict the time point of the previous time
- the Sun reached a specific elevation derivative
-
- @param latitude:float The latitude in degrees northwards from
- the equator, negative for southwards
- @param longitude:float The longitude in degrees eastwards from
- Greenwich, negative for westwards
- @param derivative:float The elevation derivative value of interest
- @param t:float? The time in Julian Centuries, `None`
- for the current time
- @return :float? The calculated time point, `None`
- if none were found within a year
- '''
- return future_past_elevation_derivative(0.01 / -2000, latitude, longitude, derivative, t)
-
-
-
-# TODO: This algorithm is imprecise, gives an incorrent sunrise and I do not fully know its behaviour
-def sunrise_equation(latitude, longitude, t = None):
- import math
- # Calculate Julian Cycle
- j_cent = julian_centuries() if t is None else t
- j_date = julian_centuries_to_julian_day(j_cent)
- j_cycle = int(j_date - 2451545.0009 - longitude / 360 + 0.5)
-
- # Calculate approximate solar noon and solar man anomaly
- approx_solar_noon = 451545.0009 + longitude / 360 + j_cycle
- solar_mean_anomaly = int(357.5291 + 0.98560028 * (j_cycle - 2451545)) % 360
-
- # Calculate solar equation of centre
- equation_of_centre = 1.9148 * math.sin(1 * solar_mean_anomaly)
- equation_of_centre += 0.0200 * math.sin(2 * solar_mean_anomaly)
- equation_of_centre += 0.0003 * math.sin(3 * solar_mean_anomaly)
-
- # Calculate solar ecliptic longitude
- ecliptic_longitude = (solar_mean_anomaly + 102.9372 + equation_of_centre + 180) % 360
-
- # Calculate solar transit
- solar_transit = approx_solar_noon + 0.0053 * math.sin(solar_mean_anomaly)
- solar_transit -= 0.0069 * math.sin(2 * ecliptic_longitude)
-
- # Calculate solar declination
- declination = math.asin(math.sin(ecliptic_longitude) * math.sin(radians(23.45)))
-
- # Calculate solar hour angle
- hour_angle = math.sin(radians(-0.83))
- hour_angle -= math.sin(latitude) * math.sin(declination)
- hour_angle /= math.cos(latitude) * math.cos(declination)
- hour_angle = degrees(math.acos(hour_angle))
-
- # Calculate time of sunset and sunrise
- sunset = 2451545.0009 + (hour_angle + longitude) / 360
- sunset += j_cycle + solar_transit - approx_solar_noon
- sunrise = 2 * solar_transit - sunset
-
- # Convert to Julian Centuries
- return (julian_day_to_julian_centuries(sunset),
- julian_day_to_julian_centuries(sunrise))
-