Arthur Carlson wrote:
> One thing that threw me is that you quoted 12 arc-sec/yr
> as the rate of shift of the Perihelion during the period 1980-2020.
> The numbers you give above for the period 2000 to 12000 amount to 66
> arc-sec/yr. Can you explain why the shift is so irregular?
Arthur,
Subtract 50 arc-secs(precession rate) from the 66 arc-secs(total
COMBINED rate change), 66-50 = 16, fairly close now to the 12 arc-secs
defined for the much shorter 40 yr. period.
In my last message I gave three principle values for defining the
EoT i.e., Obliquity, Eccentricity and the Longitude of Perihelion.
However, in considering the Longitude of Perihelion two chief components
must be recognized i.e., precession of the equinoxes and the shifting of
perihelion due to perturbation and other smaller combined effects. Lastly,
I believe the formula I am using for calculating the Longitude of
Perihelion computes it relative to a mean equinox of the date.
Luke
