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    Re: Noon sight for longitude
    From: George Huxtable
    Date: 2008 Jul 11, 16:32 +0100

    Andres Ruiz wrote-
    "The method described in Ocean Navigator is the one in Bowditch current 
    Not quite. That article suggested observing 15 minutes before and after 
    noon. Bowditch suggested a span of 30, either side. There's a big difference 
    in the resulting precision.
    There's no doubt the method can be got to work, as long as a sufficient span 
    of time is chosen, which depends to a large extent on noon Sun altitude, and 
    on the sea-state for observing. But the longer that time-span, the less 
    appropriate it is to call it a "Noon sight". To preserve that catchy title, 
    those who push this method, which is simply the old one of "equal 
    altitudes", do their best to minimise the necessary length of that interval.
    Andres' simulation would be interesting when applied to a latititude of say 
    53�N, with a declination of -23�, when a low noon Sun makes things more 
    He added-
    "Also I try this method aboard a sailboat and the results are acceptable due 
    to the waves and roll and pitch"
    That's intriguing. It would be interesting to see the numbers he came up 
    with, in real-life; and what he considered acceptable.
    contact George Huxtable at george@huxtable.u-net.com
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. 
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To , email NavList-@fer3.com

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