G'day Bernie,
On Fri, 4 Jun 1999 11:10:08 +0200, Bernie <[EMAIL PROTECTED]> wrote:
> And this is where the problem is if you want to have an exact sience (but I
> don't count astrology as one). It would enourmous (I doubt the RAM in an
> every day computer would be enough). You must understand that the planets
> and moons are affected not only by the time but by their internal
> positions. Besides the sun would also have to move, and that would also
> affect the planets. The diffrence in the modell you use and the reality is
> very small, but big enough that would make it useless for any (serious)
> astronomy.
You seem to be misinformed. Serious astronomy was one of the first
computer applications. Any home computer is quite capable of locating
every known object in the Solar System - with the accuracy limited only by
our knowledge of their orbital details; and to a precision limited only
by the machine's numerical storage limits and the programmer's desire
to retain significant digits.
Commercially available astronomical software can now, for example, locate
the Moon to within _0.1_metres_, all of the planets and their moons
to within 5-10km, and several thousand asteroids to within 20km. This level
of accuracy applies to a period of many centuries either way from today.
For more remote times, the accuracy is still more than adequate for
location purposes (or even navigating a spacecraft). The limitation is
no longer with the computer, but with our knowledge of the object's orbital
characteristics, resonances, perturbations, etc.
The same software can now also locate the million brightest stars to
a precision exceeding the resolution of any ground-based telescope; and
can also correct for the stars' actual motions through space to correctly
display the true appearance of the sky at any time for the last half-million
years or so (or the next half-million). Most programs also include the
Hubble telescope's own guide star catalogue, which contains the positions
of about 18 million objects to an accuracy exceeding 0.001 degrees.
A few of these programs will also interface with the US Naval Observatory's
"A 2.0" catalogue, which is the world's largest (about 520 million stars).
And of course these programs also include huge lists of galaxies, nebulae,
clusters and whatnot; can be updated from professional astronomical websites,
and will print charts for any date/time/location including views from other
planets...
I can say all this with assurance because I _use_ this sort of software
on my home computer, and I'm doing serious astronomical research and
inquiry with it. I've also written astronomical software on many occasions.
If you are interested in this aspect of programming, then I highly recommend
the book "Astronomical Algorithms" by Jean Meeus (see www.willbell.com).
And how much computer power do you need to run this wonderful software?
Guide 7.0 (http://www.projectpluto.com) does all of the above and more, and
its DOS version requires the following minimum system: 386sx, 2MB RAM, VGA
display, CD-ROM drive, DOS 5. A typical Survivor PC description!
Guide also has Win 3.1 and Win95 versions; and there are plenty of other
good astronomical programs for these systems. Not to mention all the ones
that run on Macintosh, Amiga and Linux.
But if you just want to know the general appearance of the sky and locate
the planets, then it's hard to beat good old SkyGlobe. Runs from a 360kB
floppy on any IBM-compatible with a graphics display, and it's shareware.
I've left copies of it on dozens of schools' computers in the last few
years and the kids seem to have no trouble learning to drive it.
And any of these programs will confirm that the Sun actually passes
through thirteen constellations every year (not twelve!), and that the
Moon and planets will take in a few more during their wanderings.
Incidentally, don't bother discussing _astrology_ with me. I reckon it's
all a load of fish dandruff!
cheers,
Fraser Farrell
http://www.dove.net.au/~fraserf/
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