On this page you will find the numerical values for astrodynamical constants (Speed of light, AU distance etc.)
Defining Constants
Julian day (d) = 86400 seconds (s)
Julian year (yr) = 365.25 days (d)
Julian Century (Cy) = 36525 days (d)
Speed of light (c) = 299792458 m/s OR 299792.458 km/s OR 1079252848.8 km/h
Gaussian gravitational constant (k) = 0.01720209895 (AU3/d2)½
Primary Constants
Mean sidereal day = 86164.09054 seconds (s) OR 23 hrs 56 mins 04.09054 secs
Sidereal year (quasar ref. frame) = 365.25636 days (d)
Light time for 1 AU (tauA) = 499.004783806 (± 0.00000001) seconds (s)
Gravitational constant (G) = 6.67259 (± 0.00030) x 10-11 kg-1 m3 s-2
General precession in longitude = 5028.83 (± 0.04) arcsec/Cy
Obliquity of ecliptic (J2000) epsilon = 84381.412 (± 0.005) arcsec
Derived Constants
Astronomical unit distance (c * tauA) = AU = 1.49597870691 x 1011 (± 3) m OR 149597870.691 km
Heliocentric gravitational constant (k2 AU3 d-2) = GMsun = 1.32712440018 x 1020 (± 8 x 109) m3 s-2