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    Re: Calculators
    From: Tony S
    Date: 1999 Sep 06, 9:07 PM

    Bill:
    
    Many thanks for your expansive reply. I can agree with you thoroughly as
    I have "walked the walk" through many stages since about 1976. Most of my
    early stuff was done with various HP calculators; then I reached "heaven"
    with the HP 67. This later led to the 41C/CV and TI 99/4A; then the dos & win
    computers.
    
    The learning experiences have been been most rewarding.
    
    Sure wish we would hear from Ben Smith about progress on his "yacht".
    
    Tony
    
    Bill Murdoch wrote:
    >
    > I guess my first point is that astro navigation calculators run from $10 trig
    > function calculators to Pentium IIIs.  All of them are useful.  The first $10
    > replaces several pounds of sight reduction books by solving the cosine
    > formula.  The next $25 will get you a solar almanac and replace the dip and
    > refraction tables along with the pencil needed to do the sums to reduce a sun
    > sight.   The next $50 will buy enough calculator to replace all the other
    > information in the Nautical Almanac.  The last $2000 makes it all very slick.
    >  There are good reasons for stopping anywhere along that path; especially in
    > the days of GPS when astro is basically a hobby.
    >
    > My second point is that programming a calculator (or computer) is for some
    > people fun.  Sure, it is easier to buy a Celesticomp, Palm Pilot or PC, load
    > in a program, and go to it.   But, there is a sense of accomplishment in
    > doing it yourself.  The easiest path may not be the most rewarding - it is
    > easier, cheaper, and faster to fly from Charlotte to Marsh Harbor than to
    > sail down from Beaufort, but some prefer to sail.
    >
    > My third point is that life is about learning.  Learning how to take a sight.
    >  Learning how to reduce it.  Learning how to clean and care for a sextant.
    > And, learning how all those numbers in the almanac are calculated.  Almost
    > every JN student asks where the numbers in the almanac come from.  Programing
    > your own astro calculator can be a path to that answer.
    >
    > I agree with you, the sun is easy.  After making the conversion of years,
    > months, days, hours, minuets, and seconds into a single measure of time,
    > after handling the data sight data input and the output, and keeping an
    > accuracy of 0.1', about this much program memory is needed to calculate
    > almanac data in a TI calculator:
    > Aries - 75 bytes
    > Sun - Aries plus 700 bytes
    > Moon - Aries plus 2000 bytes
    > Planets - Aries plus Sun plus 600 bytes plus for
    > Venus - 600 bytes
    > Mars - 1000 bytes
    > Jupiter - 1500 bytes
    > Saturn - 2000 bytes
    > 92 stars - Aries plus 2500 bytes
    > But, the sun is also the most useful body.   You may need no more.  (It is a
    > shame the moon's motion is so complicated.  It woudl be a good second body.)
    >
    > Bill Murdoch
    

       
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