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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: HO 211 and Calculator Almanacs
From: Tony S
Date: 1999 Sep 09, 11:27 PM
From: Tony S
Date: 1999 Sep 09, 11:27 PM
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