Roger: that's what I was afraid of. And that's why I held of buying the book until I was sure, though supporting Mr Meeus in his retirement(?) with meager book royalties is something I'm not loath to do--his Astronomical Algorithms is a masterpiece. The more I use it, the more I realize how well it's organized and how well the material is presented in each chapter. (BTW, thanks to you for your contribution to the solution of Kepler's equation; yours is the implementation I've used.) As to data sources, I'm using Meeus's abbreviated version of VSOP as well as his lunar model. With those, I can reproduce the images of eclipses on the NASA website for a given date/time/position. The next step seems to be to reproduce the maps as well, hence my interest in the Besselian elements and so on. Many thanks for the references. Best regards, Brad
On Tue, Dec 22, 2009 at 6:00 PM, Roger W. Sinnott <rsinn...@post.harvard.edu > wrote: > Brad, > > No, Meeus's Elements of Solar Eclipses book does not tell how to calculate > the Besselian elements. Rather, it LISTS these elements for all solar > eclipses from 1951-2200. Its real strength is that it provides detailed > numerical examples of how to USE these elements to calculate the path of > totality (northern and southern edge), as well as the appearance, > magnitude, > contact times, and limit curves of the partial phases. It also explains > how > to determine the circumstances of the eclipse at any specific latitude and > longitude. > > To calculate the Besselian elements themselves, if you want to, first you > need a source of highly accurate ephemerides for the Sun and Moon (such as > from the Astronomical Almanac, NASA's Horizons, or Aldo Vatagliano's Solex > shareware program). Then you need the algorithms for deriving the > elements. > These are given is such places as the Explanatory Supplement to the > Astronomical Almanac (either the 1992 or 1961 edition), or William > Chauvenet's Manual of Spherical Astronomy (various editions, 1863 to 1891; > also reprinted by Dover in 1960). Calculating the elements is actually > more > straightforward than using them to get accurate local preditions and curves > for an eclipse. > > -- Roger > > > ----- Original Message ----- > From: "Brad Lufkin" <bradley.luf...@gmail.com> > To: "Sundial Mailing List" <sundial@uni-koeln.de> > Sent: Tuesday, December 22, 2009 3:07 PM > Subject: Re: Nasa website > > > > Speaking of Meeus, does anyone know if his "Elements of Solar Eclipses" > > includes algorithms for calculating the Besselian elements of eclipses or > > just presents tables of results? Also, does the book present algorithms > > for > > calculating the paths of eclipses? It's not clear from the description on > > the bookseller's website. > > Regards, Brad > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > >
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