In the past couple of weeks I have seen several references to the JPL Horizons
website for astronomical calculations. See
http://ssd.jpl.nasa.gov/horizons.cgi . I used this site recently to generate a
solar ephemeris for 300BC for a remote location in Peru. It took a while to
learn how to choose among all the options available but in the end I found it
easy to use. This web based program provided exactly what I wanted in a useful
format to import into a spreadsheet. This is a powerful tool and I highly
recommend it.
The limited web version does provide the elements Brad wanted. Perhaps the full
HORIZON system available by telnet does but I have not tested the advanced
version.
Celebrate the return of the sun.
Regards,
Roger Bailey
--------------------------------------------------
From: "Roger W. Sinnott" <rsinn...@post.harvard.edu>
Sent: Tuesday, December 22, 2009 3:00 PM
To: "Sundial Mailing List" <sundial@uni-koeln.de>
Subject: Re: Nasa website
> 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
>
> ---------------------------------------------------
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>
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