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    Re: Tides by bearing of the moon
    From: George Huxtable
    Date: 2009 Apr 8, 21:12 +0100

    D Walden wrote-
    
    A quick, but I hope correct, calculation for the next 14 high tides with the
    moon above the horizon at New London, CT, shows the average azimuth of the
    moon is 135.4 deg with standard deviation of 3.5 deg (using 6 minute steps).
    The average LHA is 315.4 with SD=4.6.
    
    As a check, for Frank's low tide (15 in this case), average az=232.4, w/
    SD=7.4.  Average LHA, as he says, is 52.9 w/ SD of 1.9.
    
    (using NOAA tide predictions and xEphem moon positions)
    
    ======================
    
    Thank you, D.Walden, for an interesting and useful piece of work. The result
    was not what I expected at all. I would have expected to see the influence
    of the Sun tides to cause a much bigger swing in phase, over a tidal cycle.
    Those numbers will cause me to rethink a bit, which is never a bad thing.
    
    Mind you, 15 tides is only half of a complete tidal cycle, and I would be
    keen to see how the Moon azimuth at high water  ranges over a complete
    cycle. As the change should be cyclic, rather than a random scatter, a plot
    of how it varies with time, over that cycle, would be likely to tell us more
    than a standard deviation. That is, if Dave doesn't mind doing a bit more
    analysis.
    
    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.
    
    
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