At 06:49 PM 11/30/98 -0800, you wrote:
>Chris and rthe gang -
>does anyone know exactly what the "problem" will be in 2084 or 2092? What
is it that
>is going to happen to my LX-200?

The problem is similar to the PC-MSDOS problem. Dates are stored as an
offset from a reference year (Jna 1, 1980 in the case of PC's). When the
word size overflows, the date computation process fails. Hopefully, by
then, Meade will either offer a (relatively trivial) software update, that
will pick a new start-date (you'll need more current EPOCH tables by then
anyway :-)), or a complete computer transplant. With the price/performance
of computers today vs the hardware in LX200's, it won't be long before
they realize that an update would be cheaper than retaining the old
technology - with a resulting real benefit to users, and probably
substantial revenue from upgrades! THis is STRICTLY speculation. But, I
can hope - it is pretty clear that current problems with Magellen II for
the LX50 is due to a lack of memory and processor power for better
algorithms - the competition is doing much better, and Meade is bound to
feel the impact soon.

I don't know "exactly" what the arrangement is - could simply be an
assumption of the most significant digits of the Julian year. I note that
a 32-bit word can only code for a total change of 136+ years, to the
nearest second, and using longer storage for large (64349 objects!) lists
gets expensive in storage. True, most astro objects do not need date info,
but the computations need to be done in 64 bit arithmetic (or something
similar) for full significance Julian date calcs. It was probably easier
to use native 32-bit int arith than to program double precision. Who
knows? This is the gist of the issue, more detail is probably not germane.
====================
David Bonnell
Germantown, MD 20874

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