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    Re: Latitude by Lunar Distance
    From: Frank Reed CT
    Date: 2006 Oct 12, 21:01 EDT
    Hi Peter, you wrote:
    "Sure; that's interesting enough Frank, if not necessarily accurate.  For example, I've been following this topic from 3 locations (with different 'IP addresses') within Australia."
    Yep, sure. I wouldn't be shocked if both of the Australian hits on that "cones" page are yours. Most of the others have more detailed geographic information (the four views from Spain are all over the country).

    You also wrote:
    "Another matter of interest connected with this topic is the unanswered comment:
    'The correction for parallax is positive and that for refraction is
    negative. There will be an infinite number of positions where the two
    corrections can cancel one another, i.e.; the distances will be the
    same.' "
    Yes. There is an INFINITE number of points where the apparent distance will have the same value as the value I measure, but they're not randomly scattered about. Those points, infinite in number, are the points of the "cone of position". They intersect the Earth in arcs which can be approximated locally by "lines of position". Where two lines of position cross, that's your fix --one point (to some level of accuracy). This is not so different from standard celestial navigation. Every line of position consists of an infinite number of points.
    And you wrote:
    "The method you propose seems to be ingenious: top marks for devising it and bringing it to our attention. But it doesn't seem to be very practical."
    Hey, you want practical, buy a GPS receiver! <g> Practical is strictly relative when it comes to practicing celestial navigation in the year 2006. But let's be clear, the method I've described does work. Yes, it depends on observations which will challenge your skill as an observer (we all like that, right?) and test the quality of your sextant (nothing wrong with that either). The results are accurate to +/-6 miles in the positional fix (less accurate in one dimension as the Moon falls lower in the sky). Not great, but it's a neat trick if you can't see a horizon or get a level. Real celestial navigation without any horizon --real, artificial, or implied.
    "I'm only too happy to be proved wrong on this, but you have been unresponsive in providing requested details from a number of posters. This would seem to do you a disservice when it comes to stimulating further interest or serious attention."
    Hey if folks are interested, terrific. If not, 'non fa niente'. And, Peter, if you're still missing some "details", just let me know.
    42.0N 87.7W, or 41.4N 72.1W.

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