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    Re: Lat/Lon by "Noon Sun" & The Noon Fix PROVE IT
    From: George Huxtable
    Date: 2009 Apr 25, 17:35 +0100

    Thank you for the information, Hewitt.
    
    The results offered this time are entirely compatible with the rms scatter
    in longitude, using a full statistical analysis, that Dave Walden has
    estimated at around 10' rms in longitude, or a bit less than 6 miles.
    
    Indeed, those results look somewhat better than his: but not significantly
    so, in statistical terms. It would need many more tests to arrive at an
    estimate of scatter. But it shows that Hewitt's first result, with an error
    of only 1' in the deduced longitude, was something of a lucky-strike, as I
    had suspected.
    
    George.
    
    contact George Huxtable, at  george{at}hux.me.uk
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ----- Original Message -----
    From: "Hewitt Schlereth" 
    To: 
    Sent: Saturday, April 25, 2009 4:50 PM
    Subject: [NavList 8040] Re: Lat/Lon by "Noon Sun" & The Noon Fix PROVE IT
    
    
    | Here are my two worksheets for the sights on the top two lines of "noon
    1a".
    |
    | The procedure I followed is exactly the same as that on the previous
    | sheet I submitted for the sights on "noon.xls".  On these two,
    | however, I summarized the results and the differences between mine and
    | George's, on two lines in BOLDFACE toward the bottoms of the pages.
    |
    | For these two runs, the differences were 3.2' and 4.5' in the
    | Longitudes; 0.9' and 1.0' in the Latitudes.
    |
    | Hewitt
    |
    | On 4/24/09, Hewitt Schlereth  wrote:
    | > George, what I get from this is that the coordinates at the ends of
    | >  the top two rows of "noon1a" are Lat/Lons of the actual positions from
    | >  which the (perturbed) Hs's were generated. To me that means they are
    | >  in the same category as GPS fixes.
    | >
    | >  Comparing to GPS was something I was never able to do, because my
    | >  active sea days were over by the time it was in place. All I had to
    | >  judge my accuracy by was a DR. Also, my actual use of this
    | >  equal-altitude method was limited - perhaps a dozen or so times, as I
    | >  mentioned to Frank once when he asked.
    | >
    | >  As far as comparing to DRs goes, the technique gave me the same
    | >  results as advancing sun-lines did. So I trusted it. These "noon 1a"
    | >  Lat/Lons, though, give me a better standard- mathematically defined
    | >  positions - to gauge against.
    | >
    | >  So, what I plan to do is find equal (or nearly equal) altitudes from
    | >  the data in the top two rows of "noon1a" as I did before from your
    | >  ".xls" spread-sheet and see if the method continues to hold up against
    | >  what is, in effect, a virtual GPS fix.
    | >
    | >  I'll send the two worksheets in my next post.
    | >
    | >
    | >  Hewitt
    | >
    | >
    | >  On 4/24/09, waldendand---.com  wrote:
    | >  >
    | >  >  The DR is N56, W10.
    | >  >
    | >  >
    | >  >
    | >  >  >  >
    | >  >
    | >
    |
    | |
    |
    
    
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