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Re: HO 211 and Calculator Almanacs

Subject: Re: HO 211 and Calculator Almanacs
From: Tony (anthonys@XXX.XXX)
Date: Fri Sep 10 1999 - 01:27:29 EDT

Bill:

What is "this neat trick" that you mention. Is it a matter of grouping
intermediate results of long streams and then carrying on?

Thanks for the additional references.

Tony

Bill Murdoch wrote:
>
> Still another source of planetary, solar, and lunar data (and a lot more) is
> Montenbruck and Pfleger, Astronomy on the Personal Computer, Springer Verlag,
> 1994. The book contains programs in Pascal which are helpful guides for
> writing in any other language. The formulas used for the planets are (or
> seem to be) Newcombe's and for the moon are Brown's. He uses a neat trick
> with with the sine and cosine addition formulas to greatly minimize the
> number of calls to sin or cos which greatly speeds up the calculation of
> planetary pertubation terms.
>
> Also helpful is the Astronomical Almanac and The Explanatory Supplement to
> the Astronomical Almanac.
>
> Bill Murdoch



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