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    Re: Latitude by Lunar Distance
    From: Frank Reed CT
    Date: 2006 Oct 13, 12:48 -0700

    George H, you wrote:
    "Come off it, Frank! That method would, at the very
    best, be half as accurate (or twice as inaccurate) as
    longitude-by-lunar. So if he could achieve an accuracy of 6 miles
    either way, a devout lunarian could correspondingly claim 3 minutes
    for a longitude. Both would be related to the unrealistic claim of
    angular-distance measurement to 0.1 arc-minutes. Just because some
    observations on one occasion, from on land, fell within that bracket
    does not imply any such accuracy; as Frank, with a scientific
    background, should be well aware."
    
    Well, come off it, George (back at ya)! Your recent experience with
    sextants is minimal. Unless something has changed radically, your best
    instrument is a cheap, plastic Ebbco sextant [for those unfamiliar, you
    can get an old one for about $30 on ebay --they're nice low-accuracy,
    backup sextants]. Do you think it's possible that your experience is
    tainted by the mediocre accuracy of that tool? I sure do. Additionally,
    can you tell me how many times you have watched beginners use a good
    metal sextant to shoot a lunar distance? Have you organized sextant
    meetings that you're not telling us about??
    
    You also wrote:
    "And three of us have asked Frank to show how a position is to be
    deduced from a pair of such observations, showing the working. I have
    presumed that any delay in responding was because Frank was working on
    the details of how to formalise it. We were offered a nice graphical
    picture of intersecting cones, but that was not what had been asked
    for. Is that all we're going to get?"
    
    George, I explained how to do this TWICE in this thread. In fact, Dave
    W. followed the steps I gave and posted his own fix to the list which
    differed a couple of miles from mine. But not everyone understands
    things in the same fashion. I will think over it tonight and see if I
    can come up with an explanation of the clearing process suited to your
    unique needs. Now, why don't you see if you can duplicate Dave W.'s
    success... Take the observations that I posted earlier, work up two
    lines of position, and see where they cross. You do agree, I hope, that
    this problem amounts to crossing two lines of position. It's really not
    complicated AT ALL.
    
    A general comment:
    George, we all know that you have severe 'allergic reactions' to new
    ways of looking at celestial navigation. Basically, every time I've
    brought up something new on this list in the past three years, you have
    sunk into a state of denial, usually launched by a post saying that I
    am not answering your questions the way you want them answered. But
    you're missing out here, George... There's more than meets the eye in
    celestial navigation.
    
    -FER
    42.0N 87.7W, or 41.4N 72.1W.
    www.HistoricalAtlas.com/lunars
    
    
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