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    Re: Lunar distances
    From: Eric Haberfellner
    Date: 2002 Jan 27, 8:16 PM

    I recieved this message WS Murdoch. It provides more information on what is
    in the Lechter Book.
    Thank you Mr Murdoch.
    
    Eric Haberfellner
    
    -----Original Message-----
    From  WSMurdoch---.com [mailto:WSMurdoch---.com]
    Sent: Sunday, January 27, 2002 6:20 PM
    To: ehaberfe{at}rogers.com
    Subject: Re: Lunar distances
    
    
    In a message dated 1/26/02 1:39:28 AM Eastern Standard Time,
    ehaberfe{at}rogers.com writes:
    
    
    
      I am not an expert on Lunars, but I believe that Lechter gives a complete
      solution. He states:
    
      "In discovering a way to solve it [GMT by lunar distance] using only the
      Nautical Almanac and the ordinary sight reduction tables I had on board
      (H.O. 214), I experienced one of the great intellectual triumphs of my
    life.
      On the 25th day of the passage, with 500 miles to go, I was able to prove
      beyond all doubt that my clock was correct, within one minute of GMT, so
    my
      longitude was gound within 30 miles or so - ample precision for the
    upcoming
      landfall"
    
      This was in 1963. Did the Nautical Almanac still have Lunar distance
    tables
      at that time? I will have to dig into this material to figure out what
      information he actually uses from the Nautical Almanac. I don't have time
      right now.
    
      He has some equations, and gives complete examples.
    
    
    
    
    Self Contained Celestial Navigation with H.O. 208 by John S. Letcher
    contains two chapters on lunars.  The first chapter (and method) is a
    slightly simplified standard determination of the time by lunar observation
    using a modern almanac.  The second is the line of position method which has
    been discussed on this list before.  He describes his discovery of this
    second method and dates it as 1963.  He published the method in Yachting
    (February 1964) previous to Chichester's 1966 Along the Clipper Way.
    
    The line of position method needs nothing more than the normal almanac data,
    a means of sight reduction, some plotting, a favorable alignment of the
    moon, and enough bodies for a fix.
    

       
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