I was bootstrapping a calculation from first-principles-up in a project I'm working on, and I wanted to check my calculations. In constants.py, I observed a few fundamental physics constants being used that have been explicitly superseded by newer values, .e.g.:
# Heliocentric gravitational constant in meters^3 / second^2, from DE-405.
GS = 1.32712440017987e+20
This is from 1998, but the current JPL DE440/DE440 use GS = 1.32712440041279419e+20. Similarly:
GM_SUN_Pitjeva_2005_km3_s2 = 132712440042 # Elena Pitjeva, 2015JPCRD..44c1210P
DE440 dynamically fits this parameter down slightly to 132712440041.279419.
I also observe that ERAD = 6378136.6 is used by IERS and the NOVAS library, but contemporary packages use WGS84 or GRS80, which define Earth's equatorial radius as exactly 6378137.0 meters. Similarly, IERS_2010_INVERSE_EARTH_FLATTENING = 298.25642 in WGS84 is 298.257223563.
Should these be updated to modern astronomical baselines, or are they kept for legacy verification tests and/or older ephemeris files expect this exact truncation?
I was bootstrapping a calculation from first-principles-up in a project I'm working on, and I wanted to check my calculations. In
constants.py, I observed a few fundamental physics constants being used that have been explicitly superseded by newer values, .e.g.:This is from 1998, but the current JPL DE440/DE440 use
GS = 1.32712440041279419e+20. Similarly:DE440 dynamically fits this parameter down slightly to
132712440041.279419.I also observe that
ERAD = 6378136.6is used by IERS and the NOVAS library, but contemporary packages use WGS84 or GRS80, which define Earth's equatorial radius as exactly6378137.0meters. Similarly,IERS_2010_INVERSE_EARTH_FLATTENING = 298.25642in WGS84 is298.257223563.Should these be updated to modern astronomical baselines, or are they kept for legacy verification tests and/or older ephemeris files expect this exact truncation?