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Alexandre E Eremenko wrote:
>
> Sure. But to WRITE this program, you have to input pages
> and pages of terrible formulas from Meeus to your computer.

I'm developing a Windows DLL to eliminate those terrible formulas, at
least for C and C++ programmers. For lunar and planetary positions the
DLL implements the JPL DE/LE ephemerides. Built-in functions convert the
downloadable text format ephemeris files at the JPL FTP site to
the binary format compatible with a Windows platform.

Star positions come from the Hipparcos catalog; a subset of that catalog
(all stars down to mag. 2.7, and all the navigational stars) is in the
DLL. The user can augment this internal catalog by loading a text file
of star data.

For time scale conversions, precession/nutation models, coordinate
system conversions, vector math, etc., the complete IAU SOFA library of
121 routines is included.

Beginning with the 2006 edition, these three major components are the
basis for the Astronomical Almanac.

The DLL should be finished in July. I'd like to say late June, but these
things always take longer than you think. It's already at an advanced
stage, able to duplicate the solar, lunar, and planetary tabulations in
the Astronomical Almanac to full accuracy. Same for the examples of
rigorous solar and planetary reductions to apparent place in Section B.
The Polaris declination tables I used in another thread came from the
DLL too. But there's a lot of little stuff I still need to do.

The DLL will be available free to anyone who wants it. If that Google
mailing list (which I have not yet joined) has a file section, I will
put a copy there. In addition, I plan to create a web site where all the
source code will be available.

I want to emphasize that this is a Windows DLL, not an application. It
won't be useful unless you're a programmer. Also, it uses the C language
function call convention, so if you use another language, your compiler
must have that capability.

Now that I have set an approximate completion date, I had better get to
work.

   

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