def ra (self) :
"""Apparent right ascension of the sun (in degrees)."""
### Eq. (25.6), for apparent position
o = self.time.obliquity_corrected
l = self.apparent_longitude
result = Angle_R.normalized (Angle_R.atan2 (o.cos * l.sin, l.cos))
return result
def ra(self):
"""Apparent right ascension of the sun (in degrees)."""
### Eq. (25.6), for apparent position
o = self.time.obliquity_corrected
l = self.apparent_longitude
result = Angle_R.normalized(Angle_R.atan2(o.cos * l.sin, l.cos))
return result
def _at_time(self, m):
### J. Meeus, p. 103
loc = self.loc
rts = self.rts
### sid: sidereal time at Greenwich, in degrees,
### at time `m` (expressed as fraction of a day)
self.sid = sid = Angle_D.normalized \
(rts.sid.degrees + 360.985647 * m)
### n: `m` corrected by difference in
### Terrestrial Dynamical Time and UT
self.n = n = m + self.day.delta_T / 86400.0
self.alpha = alpha = Angle_R(rts.interpolator_a(n))
self.delta = delta = Angle_R(rts.interpolator_d(n))
self.ha = ha = hour_angle(sid, loc, alpha)
self.altitude = alt = altitude(delta, ha, loc)
return ha, delta, alt
def azimuth (decl, ha, lat) :
"""Azimuth of a celestial body with declination `decl` and hour angle `ha`
for latitude `lat`.
Azimuth is measured eastward from the North.
"""
### J. Meeus, p. 93, Eq. (13.5)
tan_A = \
( ha.sin
/ (ha.cos * lat.sin - decl.tan * lat.cos)
)
result = Angle_D.normalized (Angle_R.atan (tan_A).degrees)
corr = 0
if ha < 0 and result > 180 :
corr = Angle_D (-180) ### ha < 0 --> E of meridian
elif ha > 0 and result < 180 :
corr = Angle_D (+180) ### ha > 0 --> W of meridian
result += corr
return Angle_D.normalized (result.degrees)
def azimuth (decl, ha, loc) :
"""Azimuth of a celestial body with declination `decl` and hour angle `ha`
for location `loc`.
Azimuth is measured eastward from the North.
"""
### J. Meeus, p. 93, Eq. (13.5)
lat = loc.latitude
tan_A = \
( ha.sin
/ (ha.cos * lat.sin - decl.tan * lat.cos)
)
result = Angle_D.normalized (Angle_R.atan (tan_A).degrees)
corr = 0
if ha < 0 and result > 180 :
corr = Angle_D (-180) ### ha < 0 --> E of meridian
elif ha > 0 and result < 180 :
corr = Angle_D (+180) ### ha > 0 --> W of meridian
result += corr
return Angle_D.normalized (result.degrees)
def calc (self, m) :
self.__super.calc (m)
self.azimuth = Angle_D \
(360. - Angle_R.acos (self.delta.sin / self.lat.cos).degrees)
def calc(self, m):
self.__super.calc(m)
self.azimuth = Angle_D \
(360. - Angle_R.acos (self.delta.sin / self.lat.cos).degrees)
def phi(self):
"""Angular coordinate of polar coordinate system"""
return Angle_R.atan2(self._y, self._x)
def phi (self) :
"""Angular coordinate of polar coordinate system"""
return Angle_R.atan2 (self._y, self._x)
