--<pre>
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----                Standard Constants
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-- by "Michael W. Martin" <aardvark@ial4.jsc.nasa.gov>

-- Physical constants ------------------------------------

C     = 2.997924562E8       -- speed of light (m/s)

eC    = 1.6021917e-19       -- charge of electron (coulombs)
h     = 6.626196e-34        -- Planck's constant (J sec)

Amu   = 1.660531e-24        -- atomic mass unit (g)

Emass = 9.109558e-31        -- electron rest mass (kg)
Pmass = 1.672614e-27        -- proton rest mass (kg)
Nmass = 1.674920e-27        -- neutron rest mass (kg)

Avogadro = 6.022169e23      -- Avogadro's number (per mole)

Ro    = 8.31434e3           -- Gas constant, Ro, (J/mole-K°)
kB    = 1.380622e-23        -- Boltzman's const. k, (J/K°)
SB    = 5.66961e-8          -- Stefan-Boltzman's const, (W m^-2 K^4)

mu    = 6.6732e-11          -- Gravitational parameter (N m^2/kg^2)


-- Solar system

RSun     = 6.96e7           -- Solar radius (m)
mu_Sun   = 1.32712438e20    -- Mµ for sun (N m^2/kg)
MSun     = mu_s/mu          -- Solar mass (kg)
LSun     = 3.82e26          -- Solar luminosity (joules)

REarth   = 6378140          -- Earth radius (m)
mu_Earth = 3.986012e20      -- Mµ for earth (N m^2/kg)
MEarth   = mu_e/mu          -- Earth mass (kg)
EqRadius = 6378164          -- Equitorial Earth radius (m)
PRadius  = 6356779          -- Polar Earth radius (m)

RMoon    = 1.7382e6         -- Lunar radius (m)
mu_Moon  = 4.902794e12      -- Mµ for moon (N m^2/kg)
MMoon    = mu_m/mu          -- Lunar Mass (kg)

RMecury  = 0.380*Re         -- Mercury's radius (m)
MMecury  = 0.0554*Me        -- Mercury's mass (kg)

RVenus   = 0.950*Re         -- Venus' radius (m)
MVenus   = 0.815*Me         -- Venus' mass (kg)

RMars    = 0.532*Re         -- Mars' radius (m)
MMars    = 0.1075*Me        -- Mars' mass (kg)

RJupiter = 11.18*Re         -- Jupiter's radius (m)
MJupiter = 317.83*Me        -- Jupiter's mass (kg)

RSaturn  = 9.42*Re          -- Saturn's radius (m)
MSaturn  = 95.147*Me        -- Saturn's mass (kg)

RUranus  = 3.84*Re          -- Uranus' radius (m)
MUranus  = 14.54*Me         -- Uranus' mass (kg)

RNeptune = 3.93*Re          -- Neptune's radius (m)
MNeptune = 17.23*Me         -- Neptune's' mass (kg)

RPluto   = 0.5*Re           -- Pluto's radius (m)
MPluto   = 0.17*Me          -- Pluto's mass (kg)


-- Units -------------------------------------------------

DtR      = pi/180           -- degrees to radians
RtD      = 180/pi           -- radians to degrees


-- Time

AS    = 9192631770          -- Cesium cyles in atomic second
TY    = 31556925.9747       -- Tropical year(1900) to seconds
E_day = 86400               -- ephemermis day to seconds
FNtS  = 14*E_day            -- fortnight to seconds


-- Length & Distance

INtCM = 2.54                -- inches to centimeters
FtM   = 12*INtCM/100        -- feet to meters
MItF  = 5280                -- mile to feet

NMItM  = 1852.0             -- Nautical Miles to meters
NMItF  = NMItM/FtM          -- Nautical Miles to feet

AUtM  = 1.49597870e+11      -- astronomical units to meters
LYtM  = C*TY                -- light year to meters
PStM  = AUtM/tan(1/3600)    -- Parsec to meters
PStLY = PStM/LYtM           -- Parsec to light years

FURtM = MItF/8*FtM          -- furlongs to meters


-- Weight & Mass

StK   = 14.5939029372       -- slugs to kilograms
StP   = 32.1740485564       -- slugs to pounds
PtK   = StP/StK             -- pounds to kilograms


-- Temperature

FtC(x) = 5*(x-32)/9         -- Fahrenheit to Celsius
KtC(x) = x + 273.15         -- Kelvin to Celsius

-- Force

PtN   = 4.44822161526       -- pounds to newtons
PtOZ  = 16                  -- pounds to ounces


-- Torque

FPtNM = FtM*PtN             -- foot-pounds to newton-meters
IPtNM = 12*FPtNM            -- inch-pounds to newton-meters

-- Volumes

CFtL  = (12*INtCM)^3/1000    -- cubic feet to liters
CFtG  = 7.481                -- cubic feet to gal (US)
CPtOz = 1/8                  -- cups to ounces
OZtL  = CFtL/(128*CFtG)      -- ounces to liters
HHtG  = 63                   -- hogsheads to gal (US)


-- Energy

JtERG = 1e7                  -- joules to ergs
CALtJ = 4.1854               -- calories to joules
BTUtJ = 1055                 -- BTU's to joules
eVtJ  = 1.6021917e-19        -- electron volt to joules
eVtErg= 1.6021917e-12        -- electron volt to ergs

KtMev = 5.609538e29          -- kilograms to MeV
AtK   = 931.4812             -- amu to MeV