Is there a publication revealing the algorithms so that a programmer can
avoid having to buy almanacs,etc. and instead generate his own tables
and annual almanac ?

Thank you.
--
Courtney Thomas
s/v Mutiny
lying Oriental, NC

The only one I know is

Astronomy with your Personal Computer, Peter Duffett-Smith, Cambridge
University Press, 2nd ed, 1990.

It's written in old fashioned Basic, hence hard to follow, use, and
debug.

I spent some time on our circumnav porting it to Visual Basic, which
ran and produced results similar to those in the almanacs. I could
probably find that code if anyone's interested. I haven't looked at it
in five years, so it's as is, where is. While it's good, tight, well
subdivided code, there are no comments, so you'd need a copy of the
book to follow it, or take it on faith....

Jim Woodward
www.mvfintry.com


Courtney Thomas wrote in message ...
Is there a publication revealing the algorithms so that a programmer can
avoid having to buy almanacs,etc. and instead generate his own tables
and annual almanac ?

Thank you.

Thanks, Tom, for updated information.

I can't in good conscience suggest that Duffet is a good possibility
with the availability of a book that has the work done in C.

And yes, it must be a labor of love, not common sense, or something to
pass time on passage -- a circumnav takes about 4,000 hours at 8 knots
-- a good time for this sort of thing.

Jim Woodward
www.mvfintry.com

"Tom Dacon" wrote in message ...
The very best book on this subject is Astronomical Algorithms, authored by
Jean Meeus, a very highly respected Belgian mathematical astronomer, now
retired. The book is published by Willman-Bell, www.willbell.com.

Duffett's boot, cited in another response, is also good, and if you go to
the Willman-Bell site (click on Math and Celestial Mechanics on the
left-hand side of the page) you'll see others that are oriented toward such
things as planet, moon, and comet positions.

Astronomical Algorithms, at least in the first edition, came with a fairly
complete set of software written in the C programming language, but I don't
think it's included with the second edition of the book. Implementing
celestial navigation algorithms yourself from the book will be a fairly
demanding and time-consuming task, but it'll be a fascinating project as I
know from having done it myself. In fact I am right now in the process of
redeveloping the whole body of code in Microsoft's .Net programming language
C#.

For celestial navigation purposes, you won't need to go to the very highest
precision solutions, such as an astronomer would require. Meeus's book
contains a section on implementing your solutions to a suitable level of
precision, and from time to time in the text he comments on what terms you
can drop out if you're not after the highest precision possible.

As a warning, if you plan to do this just to save the cost of purchasing
annual almanacs, you'll have to value your time at nearly zero in order to
break even. I have probably invested hundreds of hours of programming time
in this pursuit, and will probably have another couple of hundred hours or
more into it by the time it's all running in .Net.

Tom Dacon


"Courtney Thomas" wrote in message
...
Is there a publication revealing the algorithms so that a programmer can
avoid having to buy almanacs,etc. and instead generate his own tables
and annual almanac ?

Thank you.
--
Courtney Thomas
s/v Mutiny
lying Oriental, NC