typo + change default temperatures + use solar-python1.19

Signed-off-by: Mattias Andrée <maandree@operamail.com>

4 files changed, 6 insertions, 783 deletions

diff --git a/DEPENDENCIES b/DEPENDENCIES
index 0f1082d..d190dd6 100644
--- a/DEPENDENCIES
+++ b/DEPENDENCIES
@@ -2,6 +2,8 @@ RUNTIME DEPENDENCIES:
 
 	python3
 
+	solar-python
+
 	argparser-python (required but can function partially if missing)
 	
 	libxcb (opt-out)
@@ -45,6 +47,7 @@ MAKE DEPENDENCIES:
 
 DEPENDENCY SOURCES:
 
+	solar-python          https://github.com/maandree/solar-python
 	argparser-python      https://github.com/maandree/argparser
 	adjbacklight          https://github.com/maandree/adjbacklight
 	auto-auto-complete    https://github.com/maandree/auto-auto-complete
diff --git a/src/__main__.py b/src/__main__.py
index b58cfdc..e93b196 100755
--- a/src/__main__.py
+++ b/src/__main__.py
@@ -561,7 +561,7 @@ if have_argparser:
                        None, True, ArgParser.standard_abbreviations())
     
     # Populate parser with possible options
-    dn = '\nUse twice or daytime and nighttime respectively'
+    dn = '\nUse twice for daytime and nighttime respectively'
     parser.add_argumented(['-c', '--configurations'], 0, 'FILE', 'Select configuration file')
     parser.add_argumentless(['-p', '--panic-gate', '--panicgate'], 0, 'Skip transition into initial settings')
     parser.add_argumented(['-g', '--gamma'], 0, 'RGB|R:G:B', 'Set gamma correction' + dn)
diff --git a/src/adhoc.py b/src/adhoc.py
index 8d3a57f..0751b1a 100644
--- a/src/adhoc.py
+++ b/src/adhoc.py
@@ -41,7 +41,7 @@ if (rgb_temperatures is None) and (cie_temperatures is None):
     # to 3700 K during the day, and 6500 K (neutral) during
     # the night. Do not use CIE xyY, hence set cie_temperatures
     # to 6500 K (neutral).
-    rgb_temperatures = ['3700', '6500']
+    rgb_temperatures = ['3500', '5500']
     cie_temperatures = ['6500', '6500']
 else:
     # If cie_temperatures is specified but not rgb_temperatures,
diff --git a/src/solar.py b/src/solar.py
index 38fa11b..c8bbea1 100644
--- a/src/solar.py
+++ b/src/solar.py
@@ -17,58 +17,7 @@
 
 # This module implements algorithms for calculating information about the Sun.
 
-from math import *
-import time
-
-
-SOLAR_ELEVATION_SUNSET_SUNRISE = 0.0
-'''
-:float  The Sun's elevation at sunset and 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_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, 0.0)
-'''
-:(float, float)  The Sun's lowest and highest elevation
-                 during civil twilight, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_NAUTICAL_TWILIGHT = (-12.0, -6.0)
-'''
-:(float, float)  The Sun's lowest and highest elevation
-                 during nautical twilight, measured in degrees
-'''
-
-SOLAR_ELEVATION_RANGE_ASTRONOMICAL_TWILIGHT = (-18.0, -12.0)
-'''
-:(float, float)  The Sun's lowest and highest elevation during
-                 astronomical twilight, measured in degrees
-'''
-
+from solar_python import *
 
 
 def sun(latitude, longitude, t = None, low = -6.0, high = 3.0):
@@ -89,735 +38,6 @@ def sun(latitude, longitude, t = None, low = -6.0, high = 3.0):
     return min(max(0, e), 1)
 
 
-
-# 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
-    '''
-    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
-    '''
-    return deg * 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
-    '''
-    return rad * 180 / 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 atleast the left operand.
-    #     More precively, it happens between cirka 1970-(01)Jan-11
-    #     16:09:02 UTC and cirka -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
-    '''
-    a = sun_geometric_mean_anomaly(t)
-    rc = sin(1 * a) * (-0.000014 * t ** 2 - 0.004817 * t + 1.914602)
-    rc += sin(2 * a) * (-0.000101 * t + 0.019993)
-    rc += 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
-    '''
-    rc = degrees(sun_real_longitude(t)) - 0.00569
-    rc -= 0.00478 * 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
-    '''
-    rc = -1934.136 * t + 125.04
-    rc = 0.00256 * 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
-    '''
-    rc = sin(corrected_mean_ecliptic_obliquity(t))
-    rc *= sin(sun_apparent_longitude(t))
-    return 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
-    '''
-    l = sun_geometric_mean_longitude(t)
-    e = earth_orbit_eccentricity(t)
-    m = sun_geometric_mean_anomaly(t)
-    y = corrected_mean_ecliptic_obliquity(t)
-    y = tan(y / 2) ** 2
-    rc = y * sin(2 * l)
-    rc += (4 * y * cos(2 * l) - 2) * e * sin(m)
-    rc -= 0.5 * y ** 2 * sin(4 * l)
-    rc -= 1.25 * e ** 2 * 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 degrees
-    @param   hour_angle:float   The Sun's elevation, in degrees
-    @return  :float             The solar hour angle, in degrees
-    '''
-    if elevation == 0:
-        return 0
-    rc = cos(abs(elevation))
-    rc -= sin(radians(latitude)) * sin(declination)
-    rc /= cos(radians(latitude)) * cos(declination)
-    rc = 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 degrees
-    @param   hour_angle:float   The solar hour angle, in degrees
-    @return  :float             The Sun's elevation, in degrees
-    '''
-    rc = cos(radians(latitude))
-    rc *= cos(hour_angle) * cos(declination)
-    rc += sin(radians(latitude)) * sin(declination)
-    return 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 seeked 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 seeked 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 degrees
-    @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 at the specified time
-                              as seen from the specified position,
-                              measured in degrees
-    '''
-    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 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))
-    ## Covert 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        Error tolerance for `requested`
-    @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
-    '''
-    t = julian_centuries() if t is None else t
-    t1 = t2 = t
-    v1 = v0 = fun(t)
-    while True:
-        if abs(t2 - t) > span:
-            return None
-        t2 += delta
-        v2 = fun(t2)
-        if (v1 <= requested <= v2) or ((requested >= v1 >= v2) and (requested <= v0)):
-            break
-        if (v1 >= requested >= v2) or ((requested <= v1 <= v2) and (requested >= v0)):
-            break
-        t1 = t2
-        v2 = v1
-    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 abs(vm) < epsilon else None
-        if v1 < v2:
-            if requested < vm:
-                t2 = tm
-            else:
-                t1 = tm
-        elif v1 > v2:
-            if requested > vm:
-                t2 = tm
-            else:
-                t1 = tm
-    return None
-
-
-
-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   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 future_past_equinox(0.01 / 2000, t)
-    
-
-def past_equinox(t = None):
-    '''
-    Predict the time point of the 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 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
-    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
-    '''
-    fun = lambda t : solar_elevation(latitude, longitude, t)
-    dfun = lambda t : (fun(t + e) - fun(t - e)) / 2
-    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):
-    # 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 * sin(1 * solar_mean_anomaly)
-    equation_of_centre += 0.0200 * sin(2 * solar_mean_anomaly)
-    equation_of_centre += 0.0003 * 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 * sin(solar_mean_anomaly)
-    solar_transit -= 0.0069 * sin(2 * ecliptic_longitude)
-    
-    # Calculate solar declination
-    declination = asin(sin(ecliptic_longitude) * sin(radians(23.45)))
-    
-    # Calculate solar hour angle
-    hour_angle  = sin(radians(-0.83))
-    hour_angle -= sin(latitude) * sin(declination)
-    hour_angle /= cos(latitude) * cos(declination)
-    hour_angle = degrees(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))
-
-
-
 def ptime(t):
     '''
     Print a time stamp in human-readable local time