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Fixed #99 - Export the AngleBetween function for outside callers.

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Don Cross
2021-04-16 20:18:25 -04:00
parent 6f379397e8
commit 6b01510b33
21 changed files with 6079 additions and 5874 deletions
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20
source/python/README.md
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@@ -950,6 +950,26 @@ Astronomy Engine for everyone! (Thank you in advance from the author.)
---
<a name="AngleBetween"></a>
### AngleBetween(a, b)
**Calculates the angle in degrees between two vectors.**
Given a pair of vectors, this function returns the angle in degrees
between the two vectors in 3D space.
The angle is measured in the plane that contains both vectors.
| Type | Parameter | Description |
| --- | --- | --- |
| [`Vector`](#Vector) | `a` | The first of a pair of vectors between which to measure an angle. |
| [`Vector`](#Vector) | `b` | The second of a pair of vectors between which to measure an angle. |
### Returns: `float`
The angle between the two vectors expressed in degrees.
The value is in the range [0, 180].
---
<a name="AngleFromSun"></a>
### AngleFromSun(body, time)

25
source/python/astronomy.py
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@@ -346,7 +346,26 @@ def _SynodicPeriod(body):
return _MEAN_SYNODIC_MONTH
return abs(_EARTH_ORBITAL_PERIOD / (_EARTH_ORBITAL_PERIOD/_PlanetOrbitalPeriod[body.value] - 1.0))
def _AngleBetween(a, b):
def AngleBetween(a, b):
"""Calculates the angle in degrees between two vectors.
Given a pair of vectors, this function returns the angle in degrees
between the two vectors in 3D space.
The angle is measured in the plane that contains both vectors.
Parameters
----------
a : Vector
The first of a pair of vectors between which to measure an angle.
b : Vector
The second of a pair of vectors between which to measure an angle.
Returns
-------
float
The angle between the two vectors expressed in degrees.
The value is in the range [0, 180].
"""
r = a.Length() * b.Length()
if r < 1.0e-8:
return BadVectorError()
@@ -4641,7 +4660,7 @@ def AngleFromSun(body, time):
raise EarthNotAllowedError()
sv = GeoVector(Body.Sun, time, True)
bv = GeoVector(body, time, True)
return _AngleBetween(sv, bv)
return AngleBetween(sv, bv)
def LongitudeFromSun(body, time):
"""Returns a body's ecliptic longitude with respect to the Sun, as seen from the Earth.
@@ -5317,7 +5336,7 @@ def Illumination(body, time):
# For planets, heliocentric vector is most direct to calculate.
hc = HelioVector(body, time)
gc = Vector(hc.x - earth.x, hc.y - earth.y, hc.z - earth.z, time)
phase = _AngleBetween(gc, hc)
phase = AngleBetween(gc, hc)
geo_dist = gc.Length() # distance from body to center of Earth
helio_dist = hc.Length() # distance from body to center of Sun