def get_hour_angle_sunrise(declination: FlexNum, lat_r: FlexNum):
""" calculates the hour angle of sunrise """
d = radians(declination)
lat = lat_r # radians
hour_angle_sunrise = degrees(
arccos(
(cos(radians(90.833)) / (cos(lat) * cos(d)) - tan(lat) * tan(d))))
return hour_angle_sunrise
def tan(self):
if self.unit.is_angle():
return umath.tan(
self.value *
self.unit.conversion_factor_to(_unit_table['rad']))
else:
raise TypeError('Argument of tan must be an angle')
def get_equation_of_time(oblique_corr: FlexNum, geomean_long: FlexNum,
geomean_anom: FlexNum, earth_eccent: FlexNum):
""" calculates the equation of time in minutes """
oc = radians(oblique_corr)
gml = radians(geomean_long)
gma = radians(geomean_anom)
ec = earth_eccent
vary = tan(oc / 2)**2
equation_of_time = 4 * degrees(
vary * sin(2 * gml) - 2 * ec * sin(gma) + \
4 * ec * vary * sin(gma) * cos(2 * gml) - \
0.5 * vary * vary * sin(4 * gml) - \
1.25 * ec * ec * sin(2 * gma))
return equation_of_time
def get_elevation(zenith: FlexNum):
""" calculates solar elevation angle at ref_datetime"""
# perform an approximate atmospheric refraction correction
# matrix hour_angle calculations
# these equations are hideous, but im not sure how to improve them without adding computational complexity
if isinstance(zenith, np.ndarray) and zenith.shape:
e = 90.0 - zenith
ar = e * 0
ar[e > 85] = 0
ar[(e > 5) & (e <= 85)] = 58.1 / tan(radians(e[(e > 5) & (e <= 85)])) - \
0.07 / tan(radians(e[(e > 5) & (e <= 85)])) ** 3 + \
0.000086 / tan(radians(e[(e > 5) & (e <= 85)])) ** 5
ar[(e > -0.575) & (e <= 5)] = 1735 + e[(e > -0.575) & (e <= 5)] * \
(103.4 + e[(e > -0.575) & (e <= 5)] * (
-12.79 + e[(e > -0.575) & (e <= 5)] * 0.711))
ar[e <= -0.575] = -20.772 / tan(radians(e[e <= -0.575]))
# scalar hour_angle calculations
else:
e = 90.0 - zenith
er = radians(e)
if e > 85:
ar = 0
elif e > 5:
ar = 58.1 / tan(er) - 0.07 / tan(er)**3 + 0.000086 / tan(er)**5
elif e > -0.575:
ar = 1735 + e * (103.4 + e * (-12.79 + e * 0.711))
else:
ar = -20.772 / tan(er)
elevation_noatmo = e
atmo_refraction = ar / 3600
elevation = elevation_noatmo + atmo_refraction
return elevation
def tand(x):
return tan(deg2rad(x))
def tan(self):
if self.unit.isAngle():
return umath.tan(self.value * self.unit.conversionFactorTo(_unit_table["rad"]))
else:
raise TypeError("Argument of tan must be an angle")