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Cleaned up and unified Earth and Moon radius constants.

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In all 4 supported languages, use consistent constant names for
Earth and Moon radii.

Use Moon's equatorial radius for rise/set timing.

Use Moon's mean radius for calculating Moon's umbra radius for
detecting solar eclipses.

Also use Moon's mean radius for determining whether the Earth's shadow
touches the Moon, for finding lunar eclipses.

Use the Moon's polar radius for distinguishing between total
and annular eclipses, with a 14 meter bias (instead of 1420 meters!)
to match Espenak data.

Use consistent unit test error threshold of 0.57 minutes for rise/set.
Updated demo test data for slight changes to rise/set prediction times.

Updated doxygen options to issue an error on any warnings.
Fixed the incorrect function name link that doxygen was warning me about.
This commit is contained in:
Don Cross
2020-05-23 13:08:25 -04:00
parent c148fa6869
commit e3255c7401
16 changed files with 207 additions and 153 deletions
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33
source/python/astronomy.py
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@@ -55,13 +55,22 @@ _MEAN_SYNODIC_MONTH = 29.530588
_EARTH_ORBITAL_PERIOD = 365.256
_NEPTUNE_ORBITAL_PERIOD = 60189.0
_REFRACTION_NEAR_HORIZON = 34.0 / 60.0
_SUN_RADIUS_KM = 695700.0
_SUN_RADIUS_AU = _SUN_RADIUS_KM / _KM_PER_AU
_EARTH_RADIUS_KM = 6371.0 # mean radius of the Earth's geoid, without atmosphere
_EARTH_ATMOSPHERE_KM = 88.0 # effective atmosphere thickness for lunar eclipses
_EARTH_ECLIPSE_RADIUS_KM = _EARTH_RADIUS_KM + _EARTH_ATMOSPHERE_KM
_MOON_RADIUS_KM = 1737.4
_MOON_RADIUS_AU = _MOON_RADIUS_KM / _KM_PER_AU
_EARTH_FLATTENING = 0.996647180302104
_EARTH_EQUATORIAL_RADIUS_KM = 6378.1366
_EARTH_EQUATORIAL_RADIUS_AU = _EARTH_EQUATORIAL_RADIUS_KM / _KM_PER_AU
_EARTH_MEAN_RADIUS_KM = 6371.0 # mean radius of the Earth's geoid, without atmosphere
_EARTH_ATMOSPHERE_KM = 88.0 # effective atmosphere thickness for lunar eclipses
_EARTH_ECLIPSE_RADIUS_KM = _EARTH_MEAN_RADIUS_KM + _EARTH_ATMOSPHERE_KM
_MOON_EQUATORIAL_RADIUS_KM = 1738.1
_MOON_MEAN_RADIUS_KM = 1737.4
_MOON_POLAR_RADIUS_KM = 1736.0
_MOON_EQUATORIAL_RADIUS_AU = (_MOON_EQUATORIAL_RADIUS_KM / _KM_PER_AU)
_ASEC180 = 180.0 * 60.0 * 60.0
_AU_PER_PARSEC = _ASEC180 / math.pi
_EARTH_MOON_MASS_RATIO = 81.30056
@@ -4981,7 +4990,7 @@ def SearchRiseSet(body, observer, direction, startTime, limitDays):
elif body == Body.Sun:
body_radius = _SUN_RADIUS_AU
elif body == Body.Moon:
body_radius = _MOON_RADIUS_AU
body_radius = _MOON_EQUATORIAL_RADIUS_AU
else:
body_radius = 0.0
@@ -6726,22 +6735,22 @@ def SearchLunarEclipse(startTime):
# Search near the full moon for the time when the center of the Moon
# is closest to the line passing through the centers of the Sun and Earth.
shadow = _PeakEarthShadow(fullmoon)
if shadow.r < shadow.p + _MOON_RADIUS_KM:
if shadow.r < shadow.p + _MOON_MEAN_RADIUS_KM:
# This is at least a penumbral eclipse. We will return a result.
kind = EclipseKind.Penumbral
sd_total = 0.0
sd_partial = 0.0
sd_penum = _ShadowSemiDurationMinutes(shadow.time, shadow.p + _MOON_RADIUS_KM, 200.0)
sd_penum = _ShadowSemiDurationMinutes(shadow.time, shadow.p + _MOON_MEAN_RADIUS_KM, 200.0)
if shadow.r < shadow.k + _MOON_RADIUS_KM:
if shadow.r < shadow.k + _MOON_MEAN_RADIUS_KM:
# This is at least a partial eclipse.
kind = EclipseKind.Partial
sd_partial = _ShadowSemiDurationMinutes(shadow.time, shadow.k + _MOON_RADIUS_KM, sd_penum)
sd_partial = _ShadowSemiDurationMinutes(shadow.time, shadow.k + _MOON_MEAN_RADIUS_KM, sd_penum)
if shadow.r + _MOON_RADIUS_KM < shadow.k:
if shadow.r + _MOON_MEAN_RADIUS_KM < shadow.k:
# This is a total eclipse.
kind = EclipseKind.Total
sd_total = _ShadowSemiDurationMinutes(shadow.time, shadow.k - _MOON_RADIUS_KM, sd_partial)
sd_total = _ShadowSemiDurationMinutes(shadow.time, shadow.k - _MOON_MEAN_RADIUS_KM, sd_partial)
return LunarEclipseInfo(kind, shadow.time, sd_penum, sd_partial, sd_total)