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    Re: long lost lunars
    From: Frank Reed CT
    Date: 2003 Dec 7, 22:13 EST
    Bruce Stark wrote:
    "In the way we work our lunars you and I are at different ends of the spectrum. I do everything the old way, not even graphing or plotting. I find it satisfying to work observations the way the old navigators did."

    I haven't been able to descibe all the approaches I've experimented with in the brief time I've been on this list. I may have given the impression that I'm in favor of computer solutions for lunars, but that isn't the case. There are many options.

    And:
    "But this approach is not going to take the world by storm. Most people shy away from anything that calls for a skill they don't already have, and the present generation has no skill at pencil-and-paper calculation. They've had no reason to develop it. The recruitment that will keep sextant navigation alive (and perhaps help put the history of navigation on an honest footing) will almost certainly come at your end of the spectrum."

    Anyone interested in celestial will eventually try the paper methods, and since it is no longer a "practical" art, I think it's very likely that more students will want the historical techniques instead of electronic approaches and also they will likely bypass mid 20th century methods like the highly refined H.O. tables.

    There are a number of reasons why we need computer solutions for celestial navigation alongside the paper methods:
    1) Some celestial enthusiasts really have no interest in the calculation. They want to see themselves handling a sextant, learning to take sights with skill, but the reduction is somebody else's problem. Those people are part of the market, so I don't disdain their preference.
    2) A quick reduction with a few dozen strokes on a keyboard (or a cell phone!) means you can take many more sights. Practice makes perfect, and you can practice shooting lunars anytime when you get instant feedback from electronic reduction.
    3) When you have a computer solution, you can do a ten-minute introduction to lunars for students, friends, etc. They can see it in practice and quick. Then those who want to can learn whatever paper method suits them as time and interest permit.

    You also wrote:
    "The only thing I take exception to is the idea that navigators had to have a chronometer to see them through the four days or so of the dark of the moon. Dead reckoning saw them through. Dead reckoning gave the continuity the chronometer provided for later generations. The purpose of nautical astronomy was simply to correct the reckoning now and then. That kept it from drifting dangerously far from the truth as the weeks and months went by."

    What I was getting at though is the next step beyond dead reckoning. Yes, dead reckoning saw them through, and it's good enough to sail around the world. It's what Slocum used for longitude as late as the 1890s (plus one lunar distance). But accurate navigation is founded on one simple thing: money. It's all about money. A ship that had accurate longitude approaching a coast at New Moon could sail with confidence and speed and get its cargo to port ahead of its competition. DR was a start, but to beyond that they needed lunars AND chronometers.

    By the same argument, for most smaller vessels, there was more profit to be made by accepting a little risk and relying on dead reckoning alone for longitude instead of spending money on a superior sextant for lunar distance observations or, even more pricey, a chronometer.

    And why is celestial navigation almost over and done with today? Because of price. When the price of two GPS receivers fell below the price of one sextant, the show was over.

    Frank E. Reed
    75% Mystic, Connecticut
    25% Chicago, Illinois


       
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