33 lines
862 B
Python
33 lines
862 B
Python
"""Various constants required by Skyfield."""
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# Definitions.
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AU_M = 149597870700 # per IAU 2012 Resolution B2
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AU_KM = 149597870.700
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ASEC360 = 1296000.0
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DAY_S = 86400.0
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# Angles.
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ASEC2RAD = 4.848136811095359935899141e-6
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DEG2RAD = 0.017453292519943296
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RAD2DEG = 57.295779513082321
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pi = 3.141592653589793
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tau = 6.283185307179586476925287 # lower case, for symmetry with math.pi
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# Physics.
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C = 299792458.0 # m/s
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GM_SUN_Pitjeva_2005_km3_s2 = 132712440042 # Elena Pitjeva, 2015JPCRD..44c1210P
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# Earth and its orbit.
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ANGVEL = 7.2921150e-5 # radians/s
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ERAD = 6378136.6 # meters
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IERS_2010_INVERSE_EARTH_FLATTENING = 298.25642
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# Heliocentric gravitational constant in meters^3 / second^2, from DE-405.
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GS = 1.32712440017987e+20
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# Time.
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T0 = 2451545.0
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B1950 = 2433282.4235
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C_AUDAY = C * DAY_S / AU_M
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