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Subject: Re: HP 48GX Sight Reduction Programs
From: George Huxtable (george@XXX.XXX)
Date: Sun Oct 07 2001 - 03:20:07 EDT
Lee Martin <glendonJLM@XXX.XXX> wrote about implementing Meeus'
algorithms and other almanac / sight reduction programs on the HP 48/49
range.
He added-
>Perhaps we should take this discussion off List?? Others who may be
>interested can follow.
My comment-
I would prefer any such discussion to remain on the list and not be shunted
off. There may well be others who have implemented Meeus' algorithms on
other machines in different ways who would be interested and may have
something to offer.
RPL (Reverse Polish Logic), as used in HP machines, presents its own
problems of incompatibility with other software. My own implementation of
Meeus' stuff (on the Casio FX730 programmable pocket calculator, now sadly
unavailable) uses the Bastard-Basic peculiar to that machine, which has its
owm limitations.
Given the basic algorithms so usefully put together by Meeus, there are
many choices to be made in implementing them, that are rather independent
of the details of the language that is used. There's a
community-of-interest here which it would be a pity to exclude.
Though tricky to progrem, I have found that my old Casio does the job well.
It has two problems. Its slowness: it takes around 5 minutes to provide a
position of the Moon, or Jupiter or Saturn (these are the worst cases). And
its inability to communicate with another computer.
There's still some development going on here, using this old Casio, in
terms of adding the ability to compute and reduce lunar-distance
observations to provide a measurement of GMT. This is turning out to have
somewhat more complexity than I expected (where have I heard that before?).
If others show an interest in lunar-distances for longitude then I will
start a thread going on that topic.
George Huxtable.
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george@XXX.XXX
George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
Tel. 01865 820222 or (int.) +44 1865 820222.
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