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Minor cleanup in Python documentation.

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This commit is contained in:
Don Cross
2021-04-01 10:43:37 -04:00
parent 4cc2a14a38
commit bbd16d299a
5 changed files with 42 additions and 23 deletions
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19
source/python/README.md
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@@ -149,6 +149,12 @@ these are used in function and type names.
<a name="constants"></a>
## Constants
The following numeric constants are exported by the `astronomy` module.
They may be of use for unit conversion.
Note: For the other supported programming languages, Astronomy Engine defines
helper constants `DEG2RAD` and `RAD2DEG` to convert between angular degrees and radians.
However, because Python defines the [angular conversion functions](https://docs.python.org/3/library/math.html#angular-conversion)
`math.degrees()` and `math.radians()`, they are not needed in the Python version.
---
@@ -159,6 +165,13 @@ these are used in function and type names.
---
<a name="C_AUDAY"></a>
### `C_AUDAY = 173.1446326846693`
**The speed of light expressed in astronomical units per day.**
---
<a name="classes"></a>
## Classes
@@ -193,11 +206,11 @@ to iterate through consecutive alternating perigees and apogees.
**Reports the constellation that a given celestial point lies within.**
The [`Constellation`](#Constellation) function returns this struct
The [`Constellation`](#Constellation) function returns a `ConstellationInfo` object
to report which constellation corresponds with a given point in the sky.
Constellations are defined with respect to the B1875 equatorial system
per IAU standard. Although `Constellation` requires J2000 equatorial
coordinates, the struct contains converted B1875 coordinates for reference.
per IAU standard. Although the `Constellation` function requires J2000 equatorial
coordinates as input, the returned object contains converted B1875 coordinates for reference.
| Type | Attribute | Description |
| --- | --- | --- |

12
source/python/astronomy.py
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@@ -37,6 +37,7 @@ import enum
import re
KM_PER_AU = 1.4959787069098932e+8 #<const> The number of kilometers per astronomical unit.
C_AUDAY = 173.1446326846693 #<const> The speed of light expressed in astronomical units per day.
_CalcMoonCount = 0
@@ -46,7 +47,6 @@ _EPOCH = datetime.datetime(2000, 1, 1, 12)
_ASEC360 = 1296000.0
_ASEC2RAD = 4.848136811095359935899141e-6
_ARC = 3600.0 * 180.0 / math.pi # arcseconds per radian
_C_AUDAY = 173.1446326846693 # speed of light in AU/day
_METERS_PER_AU = KM_PER_AU * 1000.0
_ANGVEL = 7.2921150e-5
_SECONDS_PER_DAY = 24.0 * 3600.0
@@ -3724,7 +3724,7 @@ def GeoVector(body, time, aberration):
earth = _CalcEarth(ltime)
geo = Vector(h.x-earth.x, h.y-earth.y, h.z-earth.z, time)
ltime2 = time.AddDays(-geo.Length() / _C_AUDAY)
ltime2 = time.AddDays(-geo.Length() / C_AUDAY)
dt = abs(ltime2.tt - ltime.tt)
if dt < 1.0e-9:
return geo
@@ -4196,7 +4196,7 @@ def SunPosition(time):
"""
# Correct for light travel time from the Sun.
# Otherwise season calculations (equinox, solstice) will all be early by about 8 minutes!
adjusted_time = time.AddDays(-1.0 / _C_AUDAY)
adjusted_time = time.AddDays(-1.0 / C_AUDAY)
earth2000 = _CalcEarth(adjusted_time)
sun2000 = [-earth2000.x, -earth2000.y, -earth2000.z]
@@ -6387,11 +6387,11 @@ def Rotation_HOR_ECL(time, observer):
class ConstellationInfo:
"""Reports the constellation that a given celestial point lies within.
The #Constellation function returns this struct
The #Constellation function returns a `ConstellationInfo` object
to report which constellation corresponds with a given point in the sky.
Constellations are defined with respect to the B1875 equatorial system
per IAU standard. Although `Constellation` requires J2000 equatorial
coordinates, the struct contains converted B1875 coordinates for reference.
per IAU standard. Although the `Constellation` function requires J2000 equatorial
coordinates as input, the returned object contains converted B1875 coordinates for reference.
Attributes
----------