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    Re: Latitude by Lunar Distance
    From: Dave Walden
    Date: 2006 Oct 14, 04:14 -0700

    I have indeed reproduced Frank's results using the data and
    procedures given in his postings.  I have been somewhat surprised at
    the vehemence with which people say his method
    can't/won't/shouldn't possibly work.  Particularly from those who
    seem to be saying not enough information has been given to know what he
    has done.
    The lines of position are about five miles wide for this case.  The
    intersecting lines give a parallelogram (the "cocked hat" for this
    method) with an extreme corner to corner distance of something over 5
    miles depending on the angle of intersection of the lines.
    On the "cones", it seems to me, the axis of the cone must be line
    between the star and the center of the moon.  As shown in the figures,
    the axis doesn't necessarily intersect the surface of the earth.
    Perhaps the implied iteration to find the desired latitude on the 70
    deg West longitude line is confusing to others.  Another approach,
    although less accurate, is to find the cleared distance at 38N and 39N
    and interpolate to the desired value.  This would require only 4
    calculations initially for each star and a couple more to refine the
    All and all, an interesting discussion.  I'd never done any type of
    lunar before.  (Not easy for us bubble sextant users to make this
    measurement, on the other hand, we always have a "horizon"!)  Not
    as complicated or hard as I'd thought.
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