--- In guide-user@yahoogroups.com, Bill J Gray <pluto@p...> wrote:

> Hi Agrafoi,
>
> I have never used series formulae to compute orbital elements.
> But I see that the ELP theory for the lunar motion _does_ have a
> version expressing orbital elements in the form you're looking for.
> I've only seen this in hardcopy form, in the book "Lunar Tables and
> Programs from 4000 BC to AD 8000", from Willmann-Bell:
>
> http://www.projectpluto.com/books.htm#lunar_tables
>
> As is mentioned there, one can download the terms used in the
> series for the moon's distance and ecliptic longitude and latitude.
> (By default, Guide uses these series.) The series for orbital
> elements are _not_ provided on-line (as far as I know), but the
> book does give them.
>
> ELP uses a slightly different notation, in which
>
> Lsl = D - F
> Lml = F
>
> D = 297.85020420 + 445267.11151675 t - 16.300e-4 t^2
> + 1.832e-6 t^3 - .884e-8 t^4
> F = 93.27209932 + 483202.01752731 t - 34.029e-4 t^2
> - 0.284e-6 t^3 + .116e-8 t^4
>
> where D and F are in degrees, and t = (JD - 2451545.0) / 36525,
> the time in Julian centuries from 1 January 2000.
>
> Hope this helps...
>
> Perhaps there should be an "astronomical computations" Yahoo list!
>
> -- Bill

Thanks a lot, Bill!
I'm sure there isn't any an "astronomical computations" Yahoo list, but you=
r suggestion its really very accurate and precious.
I have realised that it's impossible to find the series for orbital calcula=
tion on the web, but for me it's very difficult to find books too. I have on=
ly the book of Jean Meeus "Astronomical Formulae for Calculator" but here in=
Italy it's quite impossible to find, for example, "The Explanatory Suplemen=
t…".
So, your hel is much more precious in my eyes.

Thanks again
Agrafoi