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    Re: HP 48GX Sight Reduction Programs
    From: George Huxtable
    Date: 2001 Oct 07, 1:20 AM

    Lee Martin  wrote about implementing Meeus'
    algorithms and other almanac / sight reduction programs on the HP 48/49
    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.
    George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    Tel. 01865 820222 or (int.) +44 1865 820222.

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